PX Bee. 0) On Tis hao Fig we Oe Thesis fer the Degree of M. S. Charies G. Weeedbury Ht) THESIS For the Degree of iiaster of Seience. HMienican Agricultural Gollere. An Feonomie Study of the San Jose Seale; its Allies, History and Methods for its Extermination. a) G. Wood: ry —————— June i906. -YHESIS ~|(- An Economic Stuiy of the San Jose Scale; its Ailiss, History and Methods for its Externination, Ghavter I. Conditions and Object of the Work. During the fall of 1905 ecsrtain experiments were under- taken at the collere witl. a view of accumilating facts which wortd tend to determine the relative efficisancy of fall versus spring applications of tha lLimne-suivhur wash in the eradica- tion of San Jose seale. Three applications of the wash were made; in the fall, winter and spring respectively. The fomnia used in all cases was as roliows: 15 pounds clean stone line, 15 pounds flowers of sulvhur, and 50 gallons of water. This mixture was boiled about an hour and a half. The following patent preparations were aliso tested to determines their relative merits, compared one with another and of ali as compared to the lime-sulphir wash. Tobacco-potash, Whale-oil Soan, No. 6&6. James Good,. Philadeivhia, Pa. Caustic-potash Whale-oil Soap, No. 3. dames Good, Philadelphia, Pa. Kil-o-scalie. Griffith and Turner Co., Baitimore, Md. Horicum. Hammond Paint and Slug-shot Works, Fisnhkili- On—Hudson, N. Y. -2- Sealecide. B. G. Pratt Co., 11 Broadway, New York, N. Y. Target Brand Scale Emulsion. american Horticultural Distributing Co., Martinsburg, West Va. Target Brand Scale Destroyer. American Horticultural Distributing Co., Martinsburg, West Va. Scale svuray. Sherwcod-Carmody-Snith So., Waterviist, Berrien Co., Micn. Salimene. Monmouth Chemical Works, Shrewsbury, N. Y. One other scale remedy was triei which, although not a reacy uaie preparation, is just making its way into favor among thoss having i.ost to do with the eradication of San Jose seals. This is the kerosene-limoid mixture, commonly Known as K-L. It is made according to various formulae, de- pending on the pereentare of kerosene desired. That used by t}.a uviter was what is called a fifteen ver cent solution and is made as follows; to 30 pounds slaked lime, 7+ gallons of kerosene was added, stirring thoroughly into a thin sloppy mass. This was diluted with 414 gallons of water, violent agitation being kept up while the water was being added. It is the usual practice at the present time to spray for San Jose scale in the late winter or early spring, when the trees are in a perfectly dormant condition. If this work, usually something of a bug bear to the fruit grower, can be successfully done in the fall, some of the most objectionable features may be eliminated. Except in unusually wet séasons -3— the orchard is dryer and in better condition to work in at this time of the year than it is in the spring; owing to the greater ease cf application and to the fact that the average fruit grower has more time at his disposal in tre fall than in the spring, if done in the fall the work is much more likely to be done in a thorough manner. T}.3 necassity for thorourchnness eanniot be too strongly emphasized and its extreme importance will be broucht out in a later chapter. Perhaps the chief advantage claimed for fall spraying . however ilies in the fact that the scale itself is attacked at a season when it is supposed to be unable to offer such rreat resistance to the wash as it is in the late winter when thoroughly encased in its almost impervious coat of mail. Some work along tre line of fall svraying for San Jose scale has recently been done in other states, notably in New york and New Jersey. Although perhaps enough has not yet been done so that any final dictum may be announced, yet the apparent success of fall spraying at these places has been sufficiently encourasing to make it seem desirable to determine if spraying with the lime-sulphur wash at this time of year, is equally advantareous under Michigan conditions. The greater part of the work described in this paper was on pear, although some peach, apple and plum trees were also used, in order to see if the species of the host, within the limits of economic importance, would be an important —~4— factor in determining the efficacy of the application. Note was also taken of the effect of the various syrays upon the host plant, as to the general vigor of the sprayed compared to unsprayed trees; as to the effect of the syrays in checking any other disease that might be present, and as to the effect of the apvlication of the various spravs on the vitality of the fruit—buds. Since tne college had no plum, :-2ach or pear orchard sufficientl: infeste* with San Jose seale to afford a profi- table basis for experimentation, it was necessary to fo among tre neip? boring faz.ers and fruit growers for material. A sufficient number of plum and pear tress were found upon the farm of Mr. H. PP. Gladien of Ridge Farm, about one mile north of Lansing. This gentieran consented to the use of a portion of his orchard for experimental purpos2?s and it was at this viace that th: greater part of the work was done. Mr. Gladden's pear orchard consisted of about six hundred ten - yeer-old trees. A piot of a portion of the orchard is given in Plate I, showing the arrangerent. The trees are eishteen fe3t apart in rows twenty feet apart, except the dwarfs, which are eirhteen feet avart in rovs ten feet apart. The orenard was in heavy timothy sod about three years old. The infesta— tion of the orchard was nearly uniform and only moderately severe. In connection with the work in spraying for San Jose scale, & comparative study was maie of various other species of Coeecidae ~5— with a view of making clear the distinctions between the San Jose seale and some of its immediate allies. Especial attention was given to those scales most liable to be mistaken by the fruit grower for San Jose. An exariination was made of the college campus and the location of the infestation of San Joss scale placed unvon amap. see Plate II. ~G- Chapter If. Experinental Work. The experimental work erbraced the spraying of about four hundred trees and included the testing of eleven different Kin’s of suravs Por Can Jose serie. The trees were mostly wears but in addition to the pears svrayed there were also thirty Jana“ plums, ten peach and ten apple trees. Th3 pears and plums as has Poon before inentionedl were situatet on the farn oF H. P. Gladden; the apples were in the variety orchard of the Horticuitural Departrnent at the Soilere; the peach tres were on the farm of tir. Porter about cone mile west of Lansing. A plot cf a portion of wr. Gladden's orehard is given in Plate I. tne varieties are arranred as foliows, beginning at the right hand side of the plot; six rows of s*andard Bartlett, one row standard Hovsil, six rows dwarf Duchess, six rows dwarf Anjou, two rows standard Lawrence. The trees were sprayed as follows; Gladien's Paar GCrehard. Lime-Sulphur Wash:- October 23,10 Anjou pears; October 27, 25 Duchess pears; October 27, 25 Bartlett pears; Cetober 27, 15 Amjou pears; November 13, 13 Bartiett pears; December 9, iz Bartlett pears; December 9, 25 Duchess pears; December 9, 25 Anjou pears: March £9, 25 Duchess pears; Mareh 29, 25 Anjou pears. _-7— Janay Pius. Lime- Sulphur Wash:- October 23, 10 Japan plums; December 9, 10 Japan plums; March 29, 10 Japan plums. October 3, 10 Peaches at Porters. November 4, 5 Apples at college. December 7, 5 Apples at college. Patent Sprays in Giadtei's orabarad, Caustic-potash Whale-oil-soap: April 7, 5 Duchess pears; April 7, 5 Anjou pears. Tobacco-potash Whale-oil-soap: April 7, 5 Bartlett pears; April 7, 5 Anjou pears; April 7, 5 Duchess pears. Kil-—o-scale: April 12, 15 Howell pears, Scale—spray: April 12, 5 Bartlett; April 12, 5 Duchess; April 12, 5 Anjou. Salimene: April 12, 5 Bartlett; April 12, 5 Duchess; April 12, 5 Anjou, Secale Emulsion: April 12, 5 Bartlett; April 12, 5 Duchess; April 12, 5 Anjou. Horicum: April 12, 5 Bartlett; april 12, 5 Duchess; April 12, 5 Anjou. Scale Destroyer: April 12, 5 Bartlett; april 12, 5 Duchess; April 12, 5 Anjou. K-L: April 14, 15 Lawrence, -2-— Weather Conditions and Effect on Sprays. During all of the spraying with the lime-sulphur wash the weather was fair and cool, except for a few days following the application of the lime-sulphur wash to the avvle trees at the College on November 5th. The spraying of these trees was followed by a hard three days rain. There was practically no effect however caused by the rainfall on the anvearance of the sprayed tress. Cn April 8th, the day following ‘he aoviiecation oF the Tobacco-potash Wi.ale-oil-soan and ‘he Caustic—-potasn Whale-—c il-soap there was a rainfall of .66 inches at the coilege. On April 9th, almost im ediately following the application of Scalecide, successive light showers occurred for several hours. As this preparation emulsifies readily in water it was assumed that it would readily wash off and it was at first thought that a repetition of the apzlication would be dJesirable. The trees were ex— amined on the afternoon of the same day on wich they were sprayed however and no effect was observed from the slirnt wetting they had received in the forenoon. ‘They had not lost aed the dark and oily appearance caused by the s_ray and conse- quently they were not sprayed a second time. Deserintion of Patent Sprays. Senlecide:- Fifteen trees were sprayed with Sealecide on Aprii 9th, five each of Duci.ess, Bartlett and An jou. Seale- ‘cide is one of the so-calied soluble petroleum sprays. —~9— The formula for its use as a dormant spray is one gdalion of Scalecide to twenty galions of water. Berore dilution it has much the apsearance of machine oil. When water is adied it at once forms a milky emulsion, which remains stable in any provortion of water very satisfactoriiy. The material is very easy and convenient to use and has no disagreeable features in handling. It is non-corrcesive and doss not injure the face, eyes or clothing. It has been highly recommended by two or three experiment stations where it has been used ‘quite extensively. On April 12th, ninety trees were sprayed with the six different kinds of spray material the deserivtions of wich follow. Five trees each of Duchess, Bartistt and Anjou being used, exc2pt with Kil-o-scale, when fiftean trees of Howell were used because there vere not satisfactory sneci:.:ns of the ot’or varieties left which were :21t once in good vigor and yet infested with seale sufficicntly to affori a good basis for experirent. SaLimene:- This material is vea-green in color and about the consistency of putty except for a iittle ciear solution, perhaps about a nint on the top of a galion can. When water is added considerable stirring is necessary im order to dis- solve the material. Salimene is riade of lime, sulphur, salt and petroleum and when diluted for spraying is of a light pea-green color. When sprayed on the trees it gives them -~10— much the appearance of those treated with the lime-sulphur wash. Saiimene is prepared for spraying by mixing one galion Salimene with from sixteen to twenty gallons of water. Scale-spray:-— The appearance of this preparation is some- what similar to that of scaléfcide, being oily and rather colorless, but seemingly of a thinner and lighter nature than scalefcide. When water is added an emulsion is readily formed. The emulsion, while white, seems to be very thin and has the apvearance of water to which a little milk has been added. The dilution of this material which is recommended by the manufacturer for a dormant spray, is one gallon Seale- spray to twenty galions of water. Target Brand Seaie Emuilsion:— This material has the characteristic machine oil appearance of many of the petroleum prepatations. The sample used by the writer, however made a very unsatisfactory emulsion in cold water. Lumps of oily, greasy material collected on the surface of the water and would not dissolve. Sone of the preparation seemed to mix with the water maxing it a dirty whitish color, but it separated eonstantly and collected on the surface in lumps which were hard to strain out when putting the migture in the spray barrelf and made a slimy coating over funnel and inside of the mixing barrel. Moreover some difficulty was experienced later in spraying as some of the viscid insoluble portion got ‘into hose and nozzle ‘and while not causing a complete stoppage -li- of the rlow,was difficult to force out. When the barrel was rinsed preparatory to putting in another kind of spray, lumps of grease came out which had collected during the time the spraying was in progress. Horicum:- This is a dark preen material, one of the lime- sulphur coripounds, and has a very offensive odor doubtless due to the decomposition of some of the sulphur comyounds. It is of a semi-soiid consistency and must be shaken out of the ean. It dilutes very readily in cold water, the fommla being one galion of Horicum to sixteen or twenty gailions of water. When water is added and the material is ready for use it forms a dark pea-freen spray which shows up well on the trees when dry, giving them a whitewashed annearance. Target Brand Scale Destroyer:-— This is manufactured by the same company that makes the Target Brand Scale Emulsion. Scale Destroyer is a heavy, slugrish, dark liquid, resembling black molasses in color and consistency. It forms a milky emulsion with cold water with a fair degree of ease, about five minutes vigorous stirring being required to secure a uniform emulsion. The formula is one galion of the Sale Destroyer to twenty galions of water. Kil-o-seale:- This is another oily looking compound. Instead of being comparatively clear however, as Scale-cide, it has a muddy brown color when stirred. On standing a clearer portion separates and comes to the top, leaving a heavier -12- brown layer at the bottom. Care must always be taken on this aceount to thoroughly shake or stir the seontainizng vessel before emptying the Kil-o-scale out. The necessity of this stirring is recognized and emphasized bv the manufacturer. When water is added Kil-—o-scale makes a food emulsion and is easy and pleasant to handle. Tobacco-potash @Mhale-oil Soap:- When not dissolved in water this material is a dark brown color and is thick snowsh so that it pours out of the keg or barrel very siowly. As would be expected, it has the characteristic fishy odor of whale oil preparations but no smell of tobacco was percéptible. It was used at the rate of one pound of the soap to one galion of water. The soap was put in a fifty galion barrel, the right amount of water poured in, then steam was turned in through a hose. By the time the water had come to the boiling point the soap had about all dissolved. The material was sprayed on the trees while still hot, as wien cold it tends -_to jellify and is then difficult to force through the nozzle. CGaustic—-potash Whale-oil Soap:- This has practically the same appearance and possesses the same odor as the other soap. It was somewhat thicker however, and took longer to go into solution, but this was thought to be due to the pre- vious cold weather to which it had been exposed and to which the Tobacco-potash Whale-oil soap had not been. The formula _ was the same as for the other soap and no difference was ~14— observed in the effect on the tree ar in the aprearance when sprayed. K-L:- The Kerosene-limoid preparation, commonly known as K-L, is a mixture of kerosene and lime diluted with water. It has been quite extensively used at the Delaware Agricultural Experiment Station and is highly recor. ented in sus varts of the country. Some of the advantages claimed for K-L are that it is easily made without heating materials; moderate in cost, pleasant to handle, effective and adhesive, requires no straining, is plainly visible on the tree and is absolutely uniform in the percentage of kerosene in any part of the mixture. Not quite all of these clains of its advocates were borne out in ti:s experience of the writer. The method of making it has already been touched upon in shautar Te The lime used was sifted air slaked lime, although nearly any form of lime is said to be effective. The most important point to be observed in making K-L is to be sure to geta good emulsion. This is supposed to be obtained by violent and continued agitation of the mixture while the water is being adied. The difficulty in securing this emulsion, and the danger of the mixture if it is not secured, appear to be the greatest disadvantage of the kerosene-limoid combination. The air slaked lime precipitates rather rapidly in the spray tank and a good agitation is a necessity, otherwise the lime -packs against the sieve or the bottom of the num and shuts —-14-— off the flow of liquid. In ti: respect of ciirabiiity of suspension, K-L coryares unfavorably with the lime-sulphur washes. Subsequent Observations. About an hour after the application of Scalecide on April oth several light showers fell. It was thought that perhavs the material might have washed off, so an inspection was made on the afternoon of the same day. The trees were Plainly distinguishable from those not sprayed, by the dark and oily appearance of the bark. The Bartletts sprayed were not infested badly enough to judge of the number of scales killed. On Duchess and Anjou the scales had not sloughed off at all but appeared shfivellied up. The application of the Whale-oil soaps was folilowed by a more or less continuous rainfall during the succeeding eiphteen hours, about six or eight hours having elapsed between the spraying and the beginning of the rain. The trees were sprayed on April 7th and were exxumined April 10th. As this is a caustic preparation and the bark of the tree actively absorbs the potash the effect of the soap would be felt within avery short time after the apylication, and tie inseeticidal pronerties of the rreavaration might have been expeeted to ret, in their work before the rainfall bteran. This was evidently the case as all the scales anpeared to be dead when examined April 10th, having turned from the normal lemon yellow color -~15—- of life to a dark orange. They had not sioughed off however. The material, notwithstanding the rainfall subsequent to the application, was still plainly visible on the trees giving them a whitened appearance as though covered with dried soap— suds. The bark likewise ad an oily feeling +o—the—terenr. April 20th,- fen days later the trees were examined again. Trose sprayed with soap still had t'.o \iiitened appearance. Trees sprayed with Horicum were most conszicuous in the orchard. The whitewashed appearance ied not isft them in the least. The material apparently doses not wash off. No fruit buds seemed to have beon injured as all were beginning to cet green. No live scales were found beneath the white eoating on the trees. Trees sprayed with Salimene were likewise noticeably whitened byt the coating was not so heavy as those receiving Horicum. The trees sprayed first with Salimen@, which received the material from the bottom of the tank, were much whiter, showing that the settling is comparatively rapid. In this respect Salimene seems inferior to Horicum. No fruit buds were injured and only a small percent of live scale, found. No difference was observable in the appearance of trees eovered with Kil-o-scale and those which had not been sprayed at all. K-L. These trees were quite conspicuously whitened and the material apvears to stay on well. No fruit buds were -16- injured and no live scale were found. Avril 28,- On tris Aicte the final examination of the whole orehnrd wes made. On trees szrayed in f411 with the iime sulphur wash by far the greater part of the scerles were dead but enough were found alive to perpetuate tie breed the coming season. In estimating percentage of dead scales only those were considered to be dead which were shrivellied and wihhout juice. The matter of a simple test of death is one which should receive more attention than has i:iitherto been given it. It is sometines claimed that an orange colored seale is dead and that when alive they are of a light lemon yellow. The distinction holds true in the main, but the writer hes found many scales of an orange color which were full of juice and apparently thriving; on the other hand scales are frequently found which have the lemon yellow color of most living scales but which are juiceless, shrunken and apparently dead. In view of this difficulty, one is tempted to question the accuracy of many published statements as to the exact per-— centages of dead scales in an orchard. On the basis for dis- tinetion between dead and liviug seales civen above, it was sorewhat eneouragring to find that there was hardly a dead scale in the row adjoining the fall sprayed trees, which had received no treatment. On fall sprayed trees the lime sulphur ,coating was barely distinguishable; on winter syvrayed trees the spray was scarcely more néticeable, while on those sprayed -17- in the latter part of March the lime sulphur coating was very plainly visible. On the winter evraved trees in places where the lime sulphur coating was visible, a few live seales were found beneath the coating of spray. Te se:32 eo cision was found -- In sore vlaces on fall Sirayend tress. Patent Sprays. Kil—-o-sceales:- In some places no live scales could be found, at others there were plenty to make trouble the coming surmer. Scale-spray:- Material slightly visible, apvearing iike dried soapsuds, numerous live scales. Scaleciie:—- No serles were found alive. Secale Emulsion:- Live Beale? arvarantiy quite abundant. The bright yeliow color had been preserved however in the dead scales making them very difficult to distinguish from the living insects. Seale Nestroyer:- Material not visible on trees; quite a ruler of live scales. Tobacco—potash @nale-oil soap:-— No changes was noted from fhe condition reported under examimtion of April 20th. Gaustic-—potash Mhale-oil soap:- No difference observable in the action of this soap and the preceding. Salimene:-— Material apparently very durable on trees. -~18- Very few live seale could be found. Horicum:- Appearance of trees same as on April 20th. No live seale were found beneath the coating of suray material on the tress. K-L:- The lime made the trees consvicuously whitened and the coating does not wash off readily. The effect on the seale was very satisfactory. No live scales were found. Venu tear Tit, cConelusions. The Lime—-Sulphur Wash. From the known facts as to the action of the lLime-sulphur wash, that is, that its effect is cumulative and not irmediate, it seers to tie weiter that svraying in the syvring is preferable rs are indisputable acvantaces in wD to a Fali auplication, Tn fall spraving in the. -ase and eheapness of arplication, but after alt efficiency is the essential thing and ti: Vorkt ce- eerired in this oases ser1.s to indiernte tnat snvring spraying is more effective. The most beneficial action of the tine- gsulyiur wack in the ovinion of the writer is found in its work on fe young scales. If the avnvlication is made in fall and the old sealss are not ail kilied, by the tine spring cones thers js not enouch rateriali left on the tree to be effective and tre ureszeny of the survivors of the fill s:ray meet no eheck to their inerease. If these eorisiderations are triz, 1% feliocws tiat the ideal methods for the extermi- nation of the seale in a badly infested orchard is to make two anvlications, one in the fall just about the time the leaves drop, and another in the soring just before srowth bevins. The fall spray will kill the preater part of the seales, which are perhavs more susceptible to insecticires at this tine, and the spring application will prevent the survivors from multiplying. It iust ve taven tite eoisideration, hLoyever, —~20- in dealing with seale, as with many other enenies of tie farmer, thit prevention is cheaper than cure. The San Jose seale from now on will probably be a continual source of trouble in fruit growing and the bettsr way to deal with it, is to not aliow the orehard to ba half kilied b2fore taking remedial measures. If swvraying for San Jose seale be made part of the seasons routine in every orchard and a single application a season be made while the scale is not vet thoroughly established, little trouble need be expected from this source. Methods for prevaring. Many formilae and methods of preparation have been advocated for the Llime-suip ur wash. Whiie the formula uced has generally been foimd to five satisfaction, yet :n the opinion of tne writer, there ywo.ld be an advantage i11a preater proportion of limes. It is claimed by adherents of the 15-15-50 formula that the amount of lime used is sufficient to go into combination with all the s:-1phur, and that every additional bit of lime is mere whitewash. This may be true, but it is avrarent from the investigations of Mr. Haywood that fe13 Line prevents the too ravid soiution or evaporation of the insecticidal properties of the compound. These are chiefly dus to the breaking down of calcium thio- sulphate. An excess of lime, while possessing no insecticidal value in itself, holds the material on the tree longer than XComposition of the Lime-Sulphur-Salt-Wash. J. K. Haywood. -21- if just enovgh lime is used to satisfy the @hemical reactions with the sulphur. Noreover it has the additional advantage of making the spray nore plainly visible on the tree and con- sequently greater thoroughness is likely to be obtained in apylication. Twenty or twenty five pounds of line to fifteen pounds of sulphur the writer teileves makes a better wash. Much depends upon the manner of mixing the Lime and sulphur. Frequently bhe sulphur is ‘tmped on top of the water in which tne lime is slaking. When aiced in a mass in t:.is manner, the shiphur is slow to mix with the water and a longer time in boiling is required to make it do so, than if the sulphur is first mixed with a little water into a thin paste which may then be easily diluted. When enough water has been aided to about cover the required quantity of lime, this material may be out in. The water should be nearly to the boiling point when the lime is added in order to insure good Siaking. If this method is followed, every piece of lime is immediately surrounded with sulphur, a high degree of heat is generated by the slaking, and less subsequent boiling is re- quired to secure the right combination. Effect on trees: There was no injurious effect on the trees which were svrayed before the leaves had falien. No fruit buds were injured by any of the Lime-sulphur aprlications, nor were the trees harmed in any way. No difference was ob- served in the behavior of different species of hosts, in regard -22- to their suspeptibility to injury by spraying nor in regard to the susceptibility of the scales iiving upon them, to the spray. The last observation here recorded was too early in the season for a judgement to be formed as to the fungicidal value of lil.e-sulphur, and as to its value for pear-blight or yveaecn-leaf curl. Patent Sprays. The various prevared sprays may be frouped into three classes; the iime-sulphur-salt compounds, the soluble oils and the soaps. In insecticidal vaiue, there seems to be but little difference in the best scray of any of these classes. The results which the writer secured with the soluble oils do not aftori a uasis for such a flattering report con- cerning their value as has been given by some experimenters. With one very thorough apvliiecation of the oils about 90 ta 95 per cent of the seales seemed dead. Scalecide was the most satisfactory of the soluble oils. The disadvantage of Kil-o- — scale was the heavy browm precipitate which forms in the con- taining vessel on standing. scale Destroyer was fairly good but did not form an emulston so readily as Sealecide. Seale Emulsion was unsatisfactory as explained in Srarter IT, pare 16 Scalespray wnile making a fairly good emulsion fell below all the others in efficiency. As a class the soluble oil sprays have the advantage of easy preparation, wirt:ct solution; they —23— have the disadvantage of being washed off the tree by the first rain. This proves to be a serious drawback only when the application of the spray is succeeded almost immediately by rainfall. Unlike the lime-suiphur wash the effect of the oiis is almost immediate, so that a repetition of their application is unnecsassary unless the rainfall occurs within a few hours. Cf the two ready made lime-sulphur sprays used, Hordeum was more satisfactory than Salimene, because of the ease with whieh it is prepared for use. The material goes into -folution very readily, stays in suspension well, is adhesive and con- spicuous on the trees. Salimene while apparently similar in composition, is much thicker. About fifteen minutes stirring is required to dissolve it and it settles rather rapidly. Ones advantare of no inconsiderable importance which both the lime-sulphur-sxit sprays possess over the soluble oils, is their durability on the trees, They are apparently as in- pervious to water as the home-made Lime-sulvhur wash and are just as conspicuous on the trees after withstanding several rains as tie, ware just after applying. The soaps have no arparent advantare over the lime-sulphur washes or the soluble oils. On the other hand they have the disadvantares of requiring a considerable amount of time and hot water in their preparation, ani cf the necessity of making the application while the material is stili hot. —~24~ In all of the so-called patent prerarations cunsicured the item of cost has not been mentioned. Tis js For the I. reason that i4 sens to the evites that these svurays are most suitable for use in a small way, where only a few trees are to be treated. Under such conditions a few cents difference in cost is immaterial. Where a large number of trees are to be treated, the lime-sulinmur wash has no superior. When large quantities are to be used so that the jest retheds of making, bet ’ + - 9 sueh as boiling with stean, elevated tanks are LPR Oe tre cost of the Lime-sulpnur wash has been found to be less than that of anv patant vrevaration now on the market. K-le The experience with the Kerosene-iimoid mixtu2e was in the main satisfactory. This material has the advantages of adnering to the trees well, of being plainly visible and of requiring no heating in mixing. The disadvantages found in its use by tsa writer, was its rapid settling, causing a clogring of the fine screen on the bottom of the pump. rhe settling also caused the first trees sprayed to receive more than their s:iare of lime, which cf course prevented the baianee of the trees from retiing quite so much as they should. Ti os disa’vantare was due in part to the fact that air slaked tine was used. The coarse particles were removed by screening, but even then the air siinxed lime when mixed with water, will nat form nearly so flocculent a mixture as will freshly hydrated -275—- or dxy slated Lire. K-L has no injurious effect on the buds and was as efficient against the scale as any spray used. It is a fvoc4 seray and one tiat ean be made easily at home. Great care must be taken however to give violent agitation when the Kerosene is added in order to secure a permanent mixture. The difficulty of doing this prorerly is the worst eSiaure of K-L, for if a permanent mixture is not formed great danger wiil attend its use, as some of tre trees will be treated to practically pure kerosene. t Summary of Conclusions, Lime-sulphur wash: If but one ap: lication of the lime- sulphur wash is mace list it be in the spring just before growth bevins. If the orchard is badly infested spray both in fall and spring. If in a neighbornood wheres San Jose scale exists, spray for it regularly as for any other expected pest, bearing in mind that spraying is insurance on the erop. A greater proportion of lime than is contained in the 15-15-50 formula is desirable. In maxing the lime-sulphur wash first mix sulphur with a little hot water, then add enough hot water to cover the lime _to be used, then add lime, stir vigoyously and Keep the rixture boiling, addins more hot water when lime has slaked. -?6- Patent Suravs. Of the lime-sulphur preparations Horicum is ti.6 best, is durable, smooth in spraying, and effieient, but is dis- agreeable and offensive to handle. Scalecide is the best of the soluble oils. It is non- corrosive and easy to handie. It is efficient if not wasned off by rain soon after being apvlied. A slight shower does not impair tts efficiency. A8 agiass the prepared sprays are better to use ina small way where it is not desired to fo to the trouble and eyvers cf making the iire-cuiphur wash. K-L- Tis 18 a good spray if made right. Dry siared time should be used, violent agitation when the kerosene is added is essential. The danger of not securing a stable emulsion wil prevent K-L from suvplanting lime-sulphur wes: -* ym ,e Ss 7 ; ace = wets _ © For uss an ares eorziereial orelharcs, —-P7— Chapter IV. San Jose Secale on the College Campus. It had been Known for some time that there was more or less San Jose scale present about the campus at the college. It was Known that it was present in considerable quantity, infesting some of the ornamental shrubs, but whether the in- festatian had spread to other species to any great extent, how dangerous it was and how widespread, and whether it had yet attacked a very great variety of hosts, were questions that had not yet been solved. That these questions should be answered was necessary in order that the best method of dealing with the pest mignt be determined and some decisions reached as to whether it would be most economical to spray or to destroy the infested plants. Accordingly, with a view of finding out the present location of the pest and determining the best method of eradicating it, an examination of the campus was made and a map drawn. Upon this may, a photograph of which is given at Plate II, the infestations of San Jose scale were shown. The outlines, roads, walks, etc. were made by the writer by means of a stereopticdn enlargement of an old map in possession of the college. The buildings erected since the survey from which the o1d map was made, together with the trees and shrubs were located by Messrs. Spencer and Lambert of | the class of 1906. -~28- It would be manifestly impossible to examine microscopi- cally all of the plants si.own on the map, but a fairly thor- ough examination was made, especial attention being given to the most common hosts of the San Jose seaile. The number and location of the infestations are shown on the map in yeliow. It was found that the scale was present on Japan Quince in almost every place where this shrub had been set. Frequently but one or a few bushes in a bed were infested. The original source of infestation on the bushes is generally supyosed to have been from affected nursery stock, but there is strong circumstantial evidence that the first infested bushes came from the South Haven Experiment Station. Aside from the Japan Quince the scale was found upon a few scattered fruit trees® pears, plums, peaches and cherries being attacked. It seems to be characteristic of this pest that it is liable to confine its attacks to a single species of host-plant and to multiply on it for a long time with its usual rapidity, until some chance or unfavorable condition or other circumstance causes it to obtain a foothold on a host hitherto foreign to it in that particular locality, then to spread with its usual virulence on its new found prey. Hence) although now present for the most part only on Japan Quince at the college, Kt if prompt measures are not taken to eradicate it the time cannot be far distant when it will cease to confine its attacks to this shrub and may spread to the shade trees, other shrubs, or ~29~— almost any of the piants which now adorn the campus. In the ease of the Japan Quince at the college, then, the best and most economical remedy is doubtless the destruction of the affected plants. Their value either intrinsicaliv or for landscape gardening purposes is not great enough to warrant their preservation when their continued existence as a congenial host and breeding place for the San Jose scale makes them a menace to the epecies hitherto unattacked by this dreaded nest. -~30-— Chapter V. Popular Descriptions of the San Jose Scale and Some of its Close Ailies. The systematic study of the scale insects of the United States is of comparatively recent origin. Targiom Tozetti, the great Italian entomologist who did some of the earliest important work on the study of the Coccidae, is still living and writing. Professor Comstock of Cornell University, who has earned a world-wide reputation by his invaluable studies in the classification of the Coccidae of the United States, is still in the prime maturity of actwal life. The interesting family of insects known as scale insects belongs to the suborder Homoptera of the genus Hemiptera. This order takes its name from two Greek words meaning "haif- winged", the name referring to the structure of the wings in some of the genera. Homoptera likewise means "like-winged". Among the different families of the suborder Homoptera the Coccidas are distinguished by several very peculiar characters. "Inthis family we find those members of the Hemiptera which depart most widely from the type of the order. The adult female is always wingless and the body is either scalie-like or gall-like in form, or it may be grub-like and clothed with wax. The waxy covering may be in the form of powder, of large tufts or plates, of a continuous layer or of a thin scale, benseatn which the insect lives. The males of Coccidae, unlike all other Hemiptera, undergo a complete metamorphosi 8s. The adult males have only a singie pair of wings, the hind wings being represented by a pair of club-1ike halteres. Each of these is furnished with a bristie, which in all the species we have studied, is hooked and fits ina pocket in the wing on the same side. The males in the adult state have no organs for procuring food, as the mouthparts disappear during the metamorphosis of the insect and a second pair of eyes appear in their place." + For our purpose at this place however the most important thing is first, to distinguish the scale insects from others, and second to distinguish those species of scale insects which are of great economic importance from those concernfng which the fruit grower need have no particular anxiety. This wiil we taken up from the entomologists standpoint in a later chapter. At this place ket us briefly consider those characters of the scale insects which can be appreciated by the mind which has not been especially instructed in entomology, and seen by the eye unaided by the compound microscope. At present then, we need only to consider the characters whieh differentiate one sub-family of scales from other insects, because it is to this sub-family, called the Diaspinae, that all of the scale insects to which particular attention +"Manual for the Study of Insects,-- J. H. Comstock. ~22— will be given in this paper belong, except the Lecaniae. This sub-family Diaspinae includes nearly ali of the scale insects which are troublesome enemies to the fruit grower. It may be briefly said that the Diaspinae, or armoured scale group includes those species of scale insects which form a scale composed in part of moulted skins and partly of an ex- eretion of the insect. “This apparantly trivial character is correlated with important structural characters, which mark a well defined group"+. For the average man however it is simply this minute, somewhat convex, smooth and usually brown or prayish scale, which he needs to learn to recognize as being the stronghold beneath which the real insect lives. Of ali the species of scale insects which occur in the United States, numbering about eight hundred, there are con- paratively few of great economic importance. What there are occur chiefly in the following genera; Lecanium, which belongs to another sub-family than the Diaspinae and differ radically from all other genera, Aspidiotus, Mytiléysis and Chionaspis. Not much attention need be devoted here to the Lecaniae, because aithough there are a few in Michigan of economic importance, such as the Brown Apricot Scale and the Peach Lecaniunm, yet they are so different from ali other scale insects that most Lecaniums can easily be distinguished at a glance from scales +S§econd Report of the Cornell University Exp:riment station, 1882-3, J. H. Comstock. ~33— of any other genus, by their comparatively large size when mature and very convex shave. It will be necessary to do no more here than to refér to Fig. 2, Plate III. This is a photograph of a Lecanium which occurs near the Michigan Agri- cultural College on wild cherry and may serve as a type of the genus. The small holes seen in the scales are caused by parasites and show where the mature insects, the eggs of which had been laid within the scale, have made their escape. It is in the genus Aspidiotus that the worst scale enemies of Michigan fruit growers may be found. It is in this genus also that the greatest difficulty is encountered in distin- fuishing between several very closely allied species which are rendered of importance chiefly because of their close relationship to that dreaded pest of orchard and garden, commonly Known as the San Jose scale. The genus Aspidiotus takes its name from the Latin name of the shield or aspidium carried on the arm of the Roman soldier. Aspidiotus is simply the diminutive form of the word and means "little shield". The similarity in the shape and appearance of the scale of an insect of this genus ana the shield of the o1d Roman soldier is striking and the analogy is still further supported by the fact that a thriving colony of San Jose scale is nearly as well protected from the attacks of its enemies under its solid array of little shields, as was the closely—formed shieid-locked phalanx of the famous Roman legion. ‘Since the San Jose is the worst seale pest we have it may serve as the basis of a division into two classes of the common scales which the fruit grower finds infesting his trees» depending on their degree of resemblance to this dreaded pest. Following such a division as this, there would fall into the first or dangercus class first of all the San Jose scale, which Professor Comstock named in 1880, with prophetic foresight, "the pernicious scale", (Aspidiotus perniciosus. ) Closely resembling it are the Fecentriec scale (A. ancylus ) the European fruit scale, (A. ostreaeformis) and the English walnut scale, (A. juglans-regiae.) In the second or compara- tively innocuous class will come the Oyster-shell bark louse, (Mytild$sis pomorum) and the Seurfy bark louse, (Chionaspis furfurus. ) In the first division, which for convenience will be spoken of as the San Jose group, we have four species of scales which resemble each other very closely in appearance, but differ greatly in the amount of damage they may be expected to inflict. One reason for the greater destructiveness of the San Jose scale is the fact that there are several broods each season, four having been determined in the latitude of Washing- ton, D. CG. Professor Kellog of Leland Stanford Jr. Univer- sity has estimated the possible progeny of a single over wintered femais in a single season to be 3,216,080,400 scales. Another peculiarity of this scale is that it is viviparous, the young being hatched within the body of the mother and born alive. Fortunately none of its close allies approach the fan Jose in fecundity. In speaking of this arbitrarily so-called San Jose group it must be borne in mind that ther are many other species of Aspidiotus, all of which resemble each other more or less closely. But these three were se- lected because they all occur in various parts of Michigan, all work on mahy of the same host plants as the San Jose scale, and while conparatively harmiess in themselves, appear to be the scales most frequently confounded with the San Jose. Fortunately the worst of the group, the san Jose, has some characters which make it easier for the amateur to distinguish at | thir « L heath ,vhe other three from each other. In common with other species of Aspidiotus, all the members of the san Jose group have the following characters; the seale of the female is circular with the exuviae (a term applied to the moulted skins of the larval scale, which are incorporated into and form a part of mature scale) either central or more or less marginal; "seale of the male but little elongated, with the exuviae more or less central; scale usually resembling that of the female in color and texture." The exuviae are usually yellowish or light orange. On a branch where the scales are thickly crusted together, it is almost impossible to tell which of the three close relatives of San Jose a scale may be, without the aid . Of a compound microscope, and then only by an expert. -36- They are all small, circular, though sometimes irregularly so, dark gray or almost black in color, orange colored exuviae more or less central. In none of them is the adult female so nearly circular as in San Jose. The Eecentric scale usually has a brighter colored exuvium than the San Jose, and it is more frequently near the margin of the scale, rather than in the center. The exuvium of the European fruit seale is similar to that of the San Jose but the central part is not so dark and it is seldom central. One characteristic appear- ance of the bark of an infested plant is suggestive, though not proof of the presence of San Jose seale. This is a red- dish spotted discoloration on the young prowth. The scale frequently causes this discoloration and the attention is often first directed to a plant by its appearance. aA closer examination is apt to reveal the scale itself in the center of each small discolored area. The best character by which to distinguish the San Jose however is tiie prominent ring—-and- nipple on the young scales. What this is will te readily comprehended by a glance at Fig. 1, Plate IV. and at Fig. 3 Plate V. It is formed by a depressed ring with a central — protuberance. This is one of the most distinctive characters of the San Jose seale and is not nearly so plainly marked on any other syvecies. In Michigan the condition is most easily recoscnized in winter when the young are hibernating in a half grown condition. The specimen shown in the photorranph at -37— Fie. 1 Plate IV. was from a peach twig cut in January. In photographing the scales were enlarged severnl diameters, and on the natural svecimen a hand lens is necessary to see this character. Fig. 3 Plate V. is a photopranhn of a riece of apple badly infested with the scale. The ring-and-nipple shows here also. Fig. 2 is the same except that it was not magnified so much and looks much as the specimen would apynear to the unaided eys. Fig. 2 Plate III. is a photograph of Sam Jose scale on an old peach twig and shows how a severe infestation makes an ashy looking deposit on the hark. Fir. 3 Pilate IV. is of San Jose scale thoroughly covering a young twig’ of Japan Quince. This is also enlarged. Fig. 1 Plate V. shows a female scales passing the winter in the adult stage. The scale is just below the bud on the right hand side of the twig. This seems to be a favorite piace for the old females to pass the winter. In the other scales of this group which we will not attempt to further differentiate here, the scales are usually lignter colored, the orange colored exuvium is more conspicuous and more frequently near the margin of the scale and the ring- and-nipple, while occasionally present is not nearly so promi- nently developed nor so noticeable. Thé European fruit scale on a branch of spiraea is shown at Fig. 1, Plate VI. and a% the right hand side of Fig. 3. Fig. 2 Plate VI. shows another Aspidiotus, (A. aurantil) which affects citrus fruits. The specimen shown is on oranges from Caiifornia. Of the two scales mentioned as belonging in the second group, by far the most common is the Cyster shell bark louse. This scale has a world-wide distribution and is almost uni- versally present to some extent on apple trees in all parts of the country. A better idea of its appearance can be gained by reference to Fig. 1 and 3 Plate III than can be expressed in words. The specimen shown in the vhotographs are on apple twigs and are enlarged in photographing about three diameters. The scale itself is much larger than the San Jose, very convex and usually has something of a spiral or twisted apyearance. The color varies from pray to light brown. The scale of the female is long and narrow, broadened posteriorly, with the exuvium yellowish and at one end. There is but one brood a year in the north. The feraie dervosits the ergs in late summer and the body then shrinks away leaving the space beneath the scale almost filled with ergs. The > scale remains as a protection over winter. The young scales come out in May or June, crawl out upon the bark, become per- manently located and within two or three days berin the for- mation of a scale. The scale is easily recognized and unless present in very great numbers need not cause very much alarm. It is nearly everywhere present, and while it sometimes finishes a tree which old age and hard usage had weakened and devitalized already, it need not cause uneasiness if ~39— present in small quantity in a thrifty and weli cared for orchard. The other scale to be considered in the so-called innocuous class is the Scurfy bark-louse (Chionaspis furfurus). This scale belongs tn another genus than the Oyster shell bark louse though their common names are similar. Their appearance however is very different as will be seen by reference to Fig. 5 Plate VII. where a photograph is shown of the Scurfy bark louse on apnie. This scale &s very common on apple and cherry. The female is distinguished by a dull gray or white color, and is flat or irregularly oval in outline. Like the Oyster shell, it has but one brood a season in the north, the young hatching in May or June from eges laid beneath the scale the preceding summer. It is a scale from which little damage may be expected. Fig. 1 and 2 Plate VII show another secaie of this same genus, which occurs on euonymus. Fig. 2 is a part of the leaf shown in Fig. 1 enlarged more in photographing. Here is seen the type of the male scales of this genus, which are usually white and ridged or carinated. -~AG- Ghanter VI. Technical Deserinvtions of Sore of the Jomron C@ccinae. For the average fruit srower it is enouzh to be able to recornize the common types of scales which come under his observation in nis orchard. If he can distinguish the worst of trem ail, the San Jose with a fair degree of accuracy; if he Knows the generai tyve of the Asuidiotus groun to which the San Jose scale and its close allies belong, so that ':e can tell the seales for which he needs to spray from those to whicn he need pay no attention, his interest in the Soecidatis satisfied. But for the entomolosist desiring to distinguish with certainty between several of the closely allied species of Aspidiotus, such as Aspidiotus perniciosus, A. ancylus, A. ostreaeformis and A. jugians-reriae, the characters which present themselves to the unaided eye are not sufficient. The characters most used in the microscovical deternination of the Soccidae are those of the last segment of the adult fenale, called tne nygidium. An explanation of a few of the terms used for varicus appendages on this last sepment, may not be out of place. Circumgenital gland orifices or syinnerets are terms given to a number of flandular openings about the varinal orifice. Their function is supyvosed to be that of aiding in the seeretion of the wax which forms the scale. They are arranged in groups, are compound or composed of several -4]— smaller openings and the number in the aifferent grouvs is of some taxonomic imvortance. The lobes are the most consvicuous appendage, and apyear as rounded prolongations of the body-wali. Plates is the name given to small prolongations or arpen- dages which extend pnosteriorly from the body-wall from between the lobes. They may be either simmile, toothed, bifurcate or serrate. Snpines are long pointed tapering avpendages situated usually near the base of the lobes. The varying numbers, sizes, and locations of these organs and appendages form the chief distinction in the anvearance of many species of Codcidae. We shall endeavor then in this chapter to describe and figure the four above mentioned species so that there shall be no danger of confusion, and to illustrate in a general way the methods used in the identification of any of the Coccidae. One or two scales belonging to other renera will be discussed simply to serve as illustrations of the structural differences presented by different types. The outiine followed in dse- serintion will follow in a general way that used by Professor Comstock gs it appeared in the Entomological section of the Acricultural Revort for 1880. —42?-— Aspidiotus perniciosus, Somstock. The pernicious or San Jose Seale, Plate VIII. Scale of female: In outline circular, though on thickly infested areas or on rough bark often irrepularly so, slightly convex, exuviae more or less central. Color is grayish varying to dark brown or black devending somewnat on the are; the youns, especially the males being very dark. Diameter 2 mn. Female: Body light lemon yellow when alive, oval or sometimes nearly circular in outline. cegmentation is fairly distinct. Snaracters of pyridium: There are but two vairs of lobes on the nygidia of A. perniciosus. The first or mesal pair are much larger than the second, converge slightly at the caudal extremity; are usually slightly notched on the lateral margin, frequently about one-third the distance from tip to base. The second lobes are much smaller, notched on lateral margin, sometimes serrate. On the ventral surface of the margin of the pygzidium are two deep incisions each side of the meson. One incision is laterad of the base of each lobe. These incisions are rendered more prominent on account of the chitinized oval shapsd thickenings of the body-wall surrounding them. Between the mesal lobes are two small simple plates, ex- tending not quite to the tips of the lobes. Between the first and second lobes are two plates extending caudad of the first —-43— df f incision; lateraZ of the second lobe and extending caudaZ of the second incision are two or three plates, serrate on their lateral margins. Lateral of the second incision are three prominent processes extending caudal of the body-wall. These are of preat value in differentiating A. perniciosus from its allies. No other scale so far as known, possesses this character. The processes are wide at the base and deeply toothed or serrate. They are situated between the third and fourth spines. The first vair of spines are placed just laterat of the mesal lobes, the second pair lateral of the second lobes, the third vair lateral of the second incision and the fourth pair lateral of the serrate processes just mentioned. Egers are white. Male: "The mature male appears as a delicate two-winged fiy-like insect with long feelers and a single anal style projecting from the end of the body; orange in color with a faintly dusky shade on the prothorax. The head is darker than the rest of the body, the eyes are dark purple, and the antennae, legs, and style are smoky. The wings are irridescent with yellow and green, very faintly ciouded". + Distribution: very thoroughly distributed throvehout the United States. +Bulletin No. 3 New Series U. 8. Dept. Apricuiture, The San Jose Scale, its occurrences in the United states, Le O. Howard and %. L. Marlatt. ~44— Host list: Apvle, crabapyle, pear, peach, plum, Japan quince, quince, apricot, Japan plum, Satsuma plum, Prunus maritina, PrP. pissardi, P. domestica, P. avium, almond, Crataegus, per- simmon, English walnut, black walnut, Japan walnut, Lombardy poplar, Carolina poplar, golden-leaved poplar, chestnut, sumac, Gatalpa, speciosa, English wiliow, golden willow, weeping willow, laurel-leaved willow, osage orgnge, American linden, Furopean iinden, ash, dogwood, elim, orange, lemon, lime, June-berry, Acacia, Fuonymus, alder, Eucalyptus corn- nocalyx, laurel, hawthorne, snow-ball, Ptelea trifoliata, silver-maple, Spiraea, rose, strawberry, raspberry, gooseberry, currant, huckleberry, catoneaster, pecan, Actinidia, Lonicera xylosteum, Lymphoricarpus racemosus, cut—-leaved biren, milk- weed, spruce, cedar, frrape, corn. Aspidiotus ostreacformis—-Ccurtis. European fruit-scale. Plates IX and X. Scale of female: circular in outline, slightly convex, Outline varies greatly in snecimens distorted by crowding. "The central third is usually elivaceous black, the remainder dusky ochreous or drak gray". Exuviae more or less central, usually orange yellow in color though sometimes brown, The exuvium is often covered with a thin secretionary covering of wax. It is a common habit of this scale to occur in ee er -45— segregated clusters,single scales seldom being found alone. Diameter 1-2 mn. Female: Yellowish in color, ovate fo nearly circular in outline, chitinization prominent in old specimens. There are five groups of circungenital gland orifices or spinnerets, the median group contains five to eight, cephalo-laterals, seven to twelve, caudo-laterals, five to sixteen. Sepmenta- tion fairly distinct. Pygidium: There are two pairs of lobes on the margin; median lobes fairly weli developed, sliightly converging rounded, slightly notched or dented on lateral margin; second pair of iobes wider than median but much shorter and broader, Slightly notched on margin making the outline often vary. Between the mesal lobes are two small simple plates; 1ateray of the mesal lobes, extending caudad of the first incision, which is between the mesal and second lobes, are another pair of plates, usually finely serrate. Extending caudad of the second chitinized incision in the body-wall is a third group of plates which may be simple, serrate or bifurcate. "There are usually fige long spines on either side, the first at the base of the anterior margin of the median lobes; the second and third opposite, are attached to the base of the second lobe; the fourth and fifth, considerably beyong, equidistant from the second and somewhat longer, The body-wall —~46— is considerably thickened and chitinized at the base of the plates." + Male: "Male scale darker in color and smaller, one half the size of femals; cast skin raised and more or less flat. Often a siignt raised rim around the edge; central nipple present. The color is black or brown and the rim around the east skin and central nipple are often whitened." ° Distribution: Newstead states that it is widely distri- buted and “common in many parts of Furope where it appears to be a general feeder". Marlatt states that Aspidiotus ostreae- formis is now in New York, Michigan, Ohio, British Coiumbia, Ontario and Iowa. [It is also found in the west in Idaho and California. Host list: Apple, pear, plum, peach, cherry’ birch, poplar, horse-chestnut, linden, alder, Crataegus, maple, aspen, oak, date, palm, Calluma vulgaris. Aspidiotus juglans-regiae-- Comstock. The English Walnut Seale. Plate XI. Scale of female: This scale is of somewhat greater size than the others of the group considered here, being frequently 3 mm. in diameter. Adult female is circular in outline, often irregularly so where the infestation is severe, very slightly °o Bulletin 180, Michigan Agricultural College Experiment Station, some Insects of the Year 1899 by R. H. Pettit. + A Monograph of the British Coccidae. Robert Newstead. -47— convex, color gray to brown, "exuviae covered with secretion, position of exuviaeis indicated by a prominence which is pink or reddish brown. Female:Color 1ike so many similar scales, is light yellow with darker orange spots","oral setae and last segment dark yellow", segmentation fairly distinct. Pygidium: There are four or five groups of circumgenital gland orifices. The anterior group is sometimes wanting or if present consists of one to four, cephalo-laterals seven to eight, "There are two or three pairs of lobes. The median lobes are well developed and vary in outline; the second lobe of each side is less than one half as large as the median lobes, elongated and with one or two notches on the lateral margin; the third lobe is still smaller and pointed or obselete.+ On the margin are two pairs of incisions, lateral of the first or mesal lobes and the second lobes, respectively. The incisions are not deep but the chitinized thickenings of the surrounding body-wall render them conspicuous. Between the mesal lobes are two inconspicuous simple plates. Simple plates also extend caudad from each of the incisions in the body-wall. "The spines are prominent, especially thdse laterat of the second and third +} From original deseription by Prof. Comstock in the Report of the Entomologist, Year Book United States Department of Agri- -@Gulture 1880. —48— lobes; the fourth spines are a littie nearer the first lobes than the penultimate segment; and the fifth are nearer the penultimate segment. There is also a spine at or near the union of the last two segments. Scale of male: Resembles that of the female in color; "it is elongated with the larval skin near the anterior end. This skin is covered by excretion but its posterior is marked by a rose-colored prominence as in the scale of the female; the anterior part of the scale $s much more gonvex than the posterior prolongation, which is flattened. There is a rudi- mentary ventral scale in the form of two narrow longitudinal plates, one on each side of the lower surface of the scale".* Length 1.25 mm. | Distribution: This scale has been found over nearly all the United States and in Wwitzerland. Host list: Walnut, apricot, apple, pear, peach, cherry, Japan plum, locust, maple, etc. Aspidiotus ancylus. Putnam. Eecentric Scale or Putnam's Scale. Pilate XII. Scale of female: nearly circular though, frequently oval than any of its close allies; often distorted by crowding; has a marked tendency to segregation. "Exuviae laterad of . + Reference as previously. a eee a a eee —49— center and covered with thin layer of secretion. This film is white but is easily removed leaving the brick red exuviae exposed. "Scale is dark gray or almost biack with a margin of lighter gray. 1.4 mm. long and 1.3 mm wide. Female: Light yellow in color. after oviposition begins the body becomes more or less circular; previous to this it is ovate. Pygidium: Four or five groups of circumgenital gland orifices. The anterior group if present at all may sonsist of from one to six; though seldom more than three; cephalo- laterals five to eight. Only one pair of lobes is present; these are well developed and notched on the lateral margin. Occasionally there is a small notch near the end of the lobe on the mesal margin." There are two incisions in the margin of the pygidium, either side of the meson, one incision lateray of the mesal lobes and one lateral of the second Lobes. These are made conspicuous by the thickened portions of the body-wall surrounding them. There are no plates between the mesal lobes, but extending caudad of each incision are two plates, which may be either simple or toothed. The spines are located one on the base of the mesal lobes, near the lateral margin, and one lateray of each incision. "The fourth pair is at two- thirds the distance to the penultimate segment." Scale of male: "Scale of male resembles that of female in form but is smaller and more elongated. Length 1.2 m, —-50— width 0.6 mn. Distribution: This scale is fairly well distributed over the United States east of the Rocky Mountains, and is found also in Germany. Host list: Ash, beech, maple, oak, linden, peach, cherry, apple, pear, quince, osage-orange, hackberry, currant, biadder-nut, etc. Aspidiotus nerii Bouche. Plate XIII. On Cyperus aiternifolii. Chionaspis pinifolia Fitch. Pine leaf scale insect. Plate XIV. No description of these two scales will be given as neither ‘are of economic importance. Chionaspis pinifolii is common on conifers throughout the United States. Aspidiotus nerii, is &@ greenhouse pest common on oleander and frequentiy hot house plants. These are introduced simply to serve as types of the variations in character of the pygidia of different species. fhe natural appearance on their hosts is shown at Plate XV. Fig. 1 shows the typical appearance of a scale insect of the genus Aspidiotus under the magnifying glass. Figs 2 is the pine scale on Austrian pine. Fig. 3 is Aspidiotus nerii on Cyperus. —~51—- Chapter VII. A Sketeh of the History of San Jose Seale in the United States With a Brief Bibliography. Perhapvs no insect pest in the annals of economic ento- mology has caused more wide-spread alarm, been the subject of more legislation, and received more attention at the hands of Experiment workers than that ubiquitous little armoured Coececid known as the San Jose seale. The only insects that can avproach it in evil notoriety are the Rocky Mountain locust and the Colorado Potato beetle. The effect of the former was of brief duration and was comparatively localized. The potato peetle starting from its native home in the Rocky Mountain region about 1859 when potato growing had extended as far west as to invade its natural habitat, began its triumphal march Eastward. It reached the Atlantic sea-bomrd in 1874, "having traversed two-thirds of the continent in the short space of fifteen years". Potato growers have now learned to deal with this pest, however and although widely distributed it is not nearly so important a factor in potato growing as it formerly was. Unlike these pests, the San Jose scale seems not yet to have reached the climax of its destructiveness. Its natural enemies, while doubtless of some help, are not yet sufficient to hold the scale in check and sprays although used by intelli- gent orchardists are not now applied with enough thoroughness -52- the country over to anywhere near exterminate the scale. There are two facts which account in some measure for the destructiveness of this pest. The first of these is general and there have been many similar experiences in the horticul- tural history of our own country. Briefly stated it is this; that when any organism is placed under new conditions the equilibrium or balance of forces caused by the struggle for existence is upset, and rapid multiplication may be expected in the new environment until a gradual readjustment takes place. This removal of pressure upsetting the natural condi- tions of its life, has taken place with the San Jose scale. It has been nearly freed from the conditions which tended to } hold it in check in its native home; it has found large con- tiguous areas of congenial food plants; it has been almost entirely relieved from the attacks of its natural enemies, and in so far as the struggle for existence has been thus eliminated, it has spread and mltiplied. Other illustrations of this law may be observed in the ranid and destructive spread of some of the American grape diseases when unwittingly introduced into European vineyards. The downy mildew had been comparatively innocuous in America but worked havoe in France till the accidental discovery of Bordeaux mixture brought relief. The history of the Russian thistie in our country may likewise be cited as an illustration of the working of ‘this law. —~53- The other fact which accounts more directly and specifi- caily for the abundance of San Jose scale is this: the natural parasites of the insect do not seem able to adapt themselves to change in climatic conditions so rapidly as their host. The scale will spread and thrive where its parasites, which had held it in check in the locality to which it was indigenous seem unable to follow. These considerations together with the fact that San Jose seale has several broods a year in most localities, seem abundant to account for its rapid spread and its deadly menace to the plants which become infested by it. This insect was first discovered in the United States in the early seventies. It was found on the grounds of ifr. James Lick, near San Jose, California by Mr. J. H. Comstock, now professor of entomology at Cornell University. By him it was described and named Aspidiotus perniciosus or the "pernicious"scale. The name of the locality in which it was first found however, has continued to be the appellation by which it is commonly designated by horticulturists throughout the country. The plants upon which it was found on Mr. Lick's grounds were supposed to have been imported from South America and it was thought for a time that Chili might have been its native home. Later it was found on Japan plums and the scale was thought to be native to Japan. Lately however it has been found by Mr. Marlatt of the Bureau of Entomology working in the interior of China, where the possibility of outside —-54-— infection was too reriote to be considered and it is now generally agreed among entomologists that to China must be given the credit of producing this nest. after attention had been called to Aspidiotus perniciosus by Comstock, it was found in many parts of California. It spread rapidly and came to be a serious menace to the fruit growers of the Pacific coast before it was discovered in the East. It was first found in the Fast in 1893 on the grounds of Mr. C. H. Hedges of Sharlottesvilie, Va. It had previously been supposed that the climate of the Eastern United States was unfavorable for the development of this scale and hence the discovery in Virginia was viewed with alarm and perturbation by all who recognized the danger of its attacks. The source of the in- festation in Virginia was later found to have been currant bushes from a New Jersey nursery. Early in 1894 specimens from Florida were determined to be San Jose by Dr. L. 0. Howard of the Bureau of Entomology of the Department of Agriculture. "Immediately upon receipt of the Florida specimens Mr. Howard concluded that the scales had been found in three such widely separated iocalities, and as the information gained from the owners of two of the affected orchards led to the supposition that the original stock had been obtained from a large Eastern nursery, the probabilities were strong that the scale had established itself in many Eastern points during the preceding . five or six years. He therefore immediately prepared a circular of warning and had nearly 12,006 copies mailed early in April to all Eastern agricultural newspapers and to very many Fastern fruit growers." By this means many new points of infestation were discovered in the East. The source of all this infestation was undoubtedly two New Jersey nursery firms which had been sending out infested stock for several years preceding, not knowing the dangerous nature of the scale with which their stock was affected. These nurseries either in 1886 or 1887 had both received Japan plum trees from Cali- fornia, one of them direct from San Jose, the very center of Western infestation. These trees had spread the seale through- out the nurseries and through them it had been widely dis- seminated in the Eastern States. Since that time the scale has been spreading rapidly in every direction, and no fruit growing district if not already infested, need hope long to escape invasion by this pest. The San Jose scale is now so thoroughly intrenched tn nearly all parts of the country that its complete extermination can never be accomplished. It is here to stay. From now on it can be counted a permanent factor in fruit growing. But there is no cloud without its silver lining and the opinion has already been expressed that the San Jose scale is a blessing in disguise. If it causes the neglected worn out orchards which are scattered so abundantly over the state, to be either end cleaned, pruned ex sprayed or taken out! if it drives the ~56- slovenly neglected orchard out of existence, and the siovenly, careless, neglectful grower of poor fruit out of business and compels better care of remaining orchards, raises the standard of intelligence and efficiency among the remaining fruit growers, then the San Jose scale evil will indeed be a blessing in disguise and its coming will be looked back upon as marking the advent of a new era in horticulture. =—5 l= Bibliograrhy. Probably more has been printed about «he San Jose scale than about env other insect of ecoro:.iec importance, An ex- haustive bibliography of San Jose scele literature would not only contain many references to clmost the sa::e work, but would be of ro practical value and if inserted at this place would tei:'d to corfuse rather thar to aid. Only a short 1:i:t there=- fore is here appended of scme of the bulletitus and works on Coccidae which have been found by the writer to be most nelvful,. Report of the Frntomolosist -- Year Book of United States pepartment of Agriculture for 1880. J. H. Comstock. Second Resort of the Cornell University Experine.::t Station 1882-3. J. . Comstock. Manual for the Study of Insects. J. 3. Comstock. Edition of 1895. Bulletin 3 New Series, United States Department of Agriculture, Division of Entomology,- The San Jose Scale— Its Occurrence in the United States. L. 0. Howard and Cc. L. Marlatt. Bulletin 12, “ew Series,— United States Department of Agriculture, Division of Entomology,:-The San Jose Scale in 1896-1897. L. 0. howard. Bulletin 6, Technical Serics, United States Department of Agriculture, Divison of Entomology ,- The San Jose Scale and Its vearest Allies. Y. D. A. Cock*rel-. 1897, -58- The Coccid Genera Chionaspis and Hemichionasvis, Special Bulletin Hatch Experinent Station of the Massachusetts Agri- cultural College, 1899. R. A. Cooley. Bulletin 180, Michigan Agricultural College, Experirent Station,— Some Insects of the Year, 1899. R. H. Pettit. second At.nual Report of the Michisan Academ of science ,-— The Scale Insects or Coccidae. R. H. Pettit. 1900, Bulletin 200, “ichizan Acricultural College Experiment Station,— Some Insects of the year 1901. kh. H. Pettit. Bulletin 141, Virginia Agricultural Experinient Station ,- Orchard Studies XIV., The Lime-Sulphur Wash. By J. L. Phillips. 1902. Catalogue of the Coccidae of the World. Fernald. 1903. A Monograph of the British Coccidae. R. ‘Newstead, 1903. Bulletin 254, "‘‘ew York Agricultural Experiment Station,- Fall Sorayirn; “ith Sulphur Yashes. P. J. Parrott and T. A. Sirvine, 1904. Bulletin 152. Virginia Agricultural Experiiient Station,- Experinents with Caustic Soda and Some Patent Vashes Against the San Jose Scale. By J. I. Philiips, 1904. Bulletin 247, New York Agricultural Experiment Station,- The Lime-Sulphur:Soda Yash for Orchard Treatment. P. J. Parrott, S. A. Beach and H. 0. Woodworth. 1904, Bulletin 262, New York Agricultwral Experiment Station,- Sulpnur Washes for Orchard Treatment. P. J. Parrott, S. A. Beach and T. A. Sirrine. 1905. —59— American Insects,-— Kellogg . 1905. The Coccidae of Kansas. Huiter. 1905. Journal of the American Chemical Society, Vol. XXVII. Composition of the Lime Sulphur and Salt Wash. J. K. Haywsod, 1905. Bulletin 90, Mississiprl1 Agricultural Experiment Station,- The San Jose Scale in Mississivvi and the Lime-Salt Sulphur Wash, Glen W. Herrick. 1905. A study of the Lime-Sulphur-Salt-—Soda Wash. J. K. Hay- wood. (Advance Copy) 1905. Bulletin 166, California Agricultural Experi:ent Station,- Spraying for Scale Insects. H. J. Quayle, 1905. Bulletin 186, New Jersey Agricultural Experinent Station,—- Late Fall Spraying for tre San Jose or Perniciosus Scale. Jonn B. Smith. Pilate I. Plan of a portion of H. P. Gladden's pear orchard, showing varietiss and trees sprayed. The trees marred in yellow ere sprayed with the lime-sulvhur wash; otherwise as indicated by the eneiosures on map. e ox §8«& Kk & we DPPIS - 9-Piy Wns01/ 227 27P2H 2 JSBA0e/ e 4 Ss S ~~ ASoKOSZ SOT Piate II. Location of the infestations of San Jose seale on the Michivan Agricultural Sollere Campus. S MICHIGAN AGRICULTURAL COLLEGE CAMPUS a) Fic. » Fig. Fig. 3. Plate III. Oyster-shell Bark louse, (Mytilaspis pormorum) on twig of arnvile. Enlarged. Parasitized Lecanium on Wiid Sherry. Enlarred. Oyster-shell Bark louse, (mM. pomorum) on twig of avnle. (Fnlarged). tote LGV Plate IV. Fig. 1. San Jose seale (aszidiotus perniciosus) on bark of peach twig. (Fnlarged). Fig. 2. San Jose scales encrusting bark of pench branch. (Enlarged. ) Fig. 5. San Jose scale on Japan quinee. (Enlarged. ) Fuial. Fg 3. 4 Be 3. Plate V. Adult female of San Jose scale hibernati.~” «2. peach twig. (Enlarged. ) San Jose scale on fruit of avple. (Siishtiv enlarged) San Jose sceale on fruit of apnle. (Enlarred ) Photos by Mr. R. H. Pettit. Plate VI. Fie. 1. European fruit scale (Asvidiotus ostreasforr.is ) on spiraea sambucifolia. (Enlarged ) Fis. 2. Red scale of California (Aspvidiotus aurantii) on fruit of orange. (Enlarged ) At left Willow seale (Chionasvis saliicis) on poplar. en Fir. At risht Euronean fruit seale on spiraea. (Enlarged) Fred. Plate VII. Fig. 1. Chionasvis suonymi(?) n evuonymues. The small white carinated scales are males, the larger dusky ones are ferales. (Enlarged ) Fie. 2. Frortion of leaf shown in Fig. 1 stili further magnified. Fig. 3. Seurfy bark-louse (Chionasvis furfurus) on twig of apple. (Enlarged ) Pliate VIII. San Jose seale —- Asvidiotus perniciosus Pygidium of ferale. AWW Plate IX. Rurorean fruit seale (Aspidiotus ostreaeformis ) Pygidia of adult females, m8 4g Q aE ii? 2% ° e 2° > : % o Pid S © ; oo 2 ‘ od ogo ‘ y) fp és oO i) ‘ef ad pat Plate X. Ruropean fruit—-scale (Aspidiotus ostreaefornis ) Portions of pyvidia of females showing variations in mesal lobes, Plate XI. hngeiish-walnut seales--Asnidiotus jurlans-repiae. Pyfidia of Females. Pilate XIl. KEecentric scale (Asvidiotus anevlus ) Pycidium of fPermnale. > we Plate XIII. Aspidiotus nerii Bouche. Pygidium of female. oe Plate XIV. Chionasyvis pinifolii Fiteh. Margin of pygidiun of femals. Fig. 1. Fig. 2. Fig. 3. Plate XV. Typical anvnearance of a scale insect of genus Asvidiotus under the compound microscone. Pine seale, (C. Pinifolii) on Austrian pine. Asyidiotus nerii on Cyperus alternifolia. Free. 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