Ps iil CS) ok ©) NO NO WU CO ‘ Da eas ore Pa a Se Pert ee hy ew ora 4 THESIS. Se) INSECTICIDES AND FUNGICIDES. 3, €. W. Cracy. 1896. . ‘! < < , ‘ y ‘ee Se Tae SN OS iO TT OPN ON DON OY Dy PE Oran Oa Dt ES Du aa Oe Ay {resis THESIS on INSECTICIDES AND FUNGICIDES DY five : {\ UBL ‘Woodbridge Tracy. (HESIS INSECTICIDES AND FUNGIOIDES. During the last nine or ten years an increaséd interest Mas been manifested in the practice of spraying as a means of holding in check certain insect pests and diseases of plants, especially those due to fungi. In this work wonderful improve- ments have been made especially in this country where it has been stimulated by the feneral and state fovernment, and tho agricultural and horticultural press. The beneficial effects of spraying, so far as a preven- tion of injury from fungi and the attacks from insects are concerned, are now so well recognized that little indeed need “be said on the subject. Many of the most destructive diseases of our crops may be readily controlled at a comparatively gmall expense by the proper application of certain finricides. Besides preventing the injury done by fungi and insects there is still another phase of the spraying question which, although as yet has received very little attention, is of great importance. This is the effect of certain fungicides on the growth of plants independent of other considerations. Almost from the beginning of the work in this country it wes observed that when certain preparations were used as fungi- cides the plants made a better growth, yislded a better har- vest, and in some cases gave an earlier product than those untreated even though they had no disease present or any in- gects tpon then. 103925 The effect of spraying in this direction has been es- pecially marked in the case of the potato, and also where nursery stock has been under treatment. The yield of pota- toes has been frequently increased f¥om 26 to 50 % quite in- dependent of any effects produced on the plants by holding in check. fungous diseases and pest. We thus see the great in- portance of spraying. While a number of preparations and solutions used as fungicides have given promise of values none have heen found which filled so many requirements as the Bordeaux Mixture, anc it 1s probably more generally used today than all other fungicides combined. The chief points in its favor are: 1. Its thorough effectiveness as a fungicide. x. Its cheapness. 3. Its safety from a hygienic standpoint. 4. Its harmiessness to the sprayed plants. 5. Its beneficial effedt on plants other than those re- sulting from the mere prevention of the attacks of parasites, The use of Bordeaux Mixture orifinated in France in the neighborhood of the city of Modoc, which is situated on the panks of the river Gironde. It was first used as a paste and sprinkled on vines an? trellises near highways to Keep boys from pillaging the vineyards. Prof. A. Millardet professor of potany in the Acadamy of Sciences at Bordeaux France, in a visit to this region in 1882 found that the vines where this solution had been applied did not suffer from mildew. He carried on experiments to test its value with fairly good results, until in 1884 he published an account of what he had done. From that time it has rapidly come into general use. All things considered we belisvs that the best results will be obtained from the use of a mixture made by the follow- ing formula: Gopper Sulphate (cu S 0 4) 4 pounds. Fresh unslaked lime (Ca 0.H2 0) 4 " Water 40 gallons. This can be most easily mixed by placing six gallons of water in a tub or barrel and in this hang four pownds of cop- per sulphate in a burlap or other course sack. Silake the lime, being careful not to add the water fcster thon the lime will take it up. Strain the lime to remove any lumps that may not have slaked. Pour together and dilute to forty gallons. Mnougn lime should be added to neutralize the free acid for if this is not done it will injure the foliage. A good way to test this is to add a few drops of ferro-cyniade of pot-— asium to the golution before it is diluted and if it turns brown the lime is deficient and more should be adved until the ferro-cyanide shows no chanre in color. Certain chemical combinations take place from the mix- ing of the copper sulphate and the lime solution. The copper is precipitated as cupric hydroxide forminz at the same time a slightly soluble sulphate of lime. These two salts tore- ther with an excess of lime remain in suspension in the Bor- Geaux Mixture. The reactions are simple and are expressed by the formula 0us04. BH204+Cad0. H2Z0eCu( OH )24CaS0445H20. From this formula a simple calculation shows that to precipitate four pounds of copper sulphate there would be required but e389 pounacs of lime. However as the limos is usuallv vory inm- pure it has been found by careful experiments that we heed a much greater amount than this and that equal parts of lime and copper sulphate five the best results. It wili be noticed that this preparation although not as complex and not as difficult to prepare as many, taxes considerable time and more or less experience which probably has much to do with its not being used.more generally by mar- ket gardeners and those who have but a small number of plants that would be benefited by its use. To overcome this some- what serious objection it was thought best to experiment with one or nore solutions which could be easily and rapidly pro- pared with comparatively little care. As Bovdeavxs Mixture contains as much if not more coprer sulphate than lime and it has shown such remarkabie resvlts it was thought best to experiment with crystals of corper sulphate dissolved in water. The experiments with this were carried on along several lines. First. s, 4 * : aes e an pas - “EN a ‘ % " . rn w . , ’ t i . ° i Det, e* u! . “ 8 cr v4 3 * w ‘ TT . rt % " - ‘ ° * wr ek ote - 1 oe . “ - e re - - Strobplian- Lot I. Lot II. thes Dyer- danius. Sprayed on April 6 Wilted con— 0. K. siderably . # 13 Same. e * 8g0 Little better.* * 638 O. K. # May 4 a « Ageratun Sprayed on April 6 O. K. O. K. * 13 " " » 20 # " 2 98 | Mey 4 | at Achyranthes Leaves dried. Bmersonii. some. Sprayed on April 6 Looks petter. 0. K. 8 i8 0. K. ad # 920 e " # 98 " " May 4 " ad Achyranthes Lindenii. Sprayed on April 6 O. K. O. K. * 418 a " ® 920 t e # 98 w " May 4 8 w Lot IIl. Lot IV. .O. .K. O, K. Wilted some * Not as bad Lot I 6th. Better. " 6. K. . " 8 O. K. 0. K " " # i" # e ft " O. K. O. K n i t" ® " " te O. K. O. K. " i" # 8 " " " i no ” " $ # ul Achyranthes Lot T.- Hoveyil. Sprayed on April 6 O. K. * 13 t * 920 u " 28 | May 4 tt Lot II. Lot III. O,. K. O. K. i @ r r it # 8 a Lot IV. O. K. It will be noticed that there are some inconsistencies, es- pecially in case of the Primula and Strobilanthes Dyerianius which may have been caused by a difference in individual plants. Experiment II. This experiment was similar to the preceding one with the exception that soft water was used and that but nine varieties were sprayed but three times. Petunia Lot I. Sprayed on April 30 Table 2. Lot II. Lot Iil. siexly. Not oughly heal- good color. $hy. a 628 No change. May 4 " Oinneraria. Sprayed on April 20 Tips of leaves dried some. * 28 Dried up more today. May 4 No further change. No change. " ? if ? 0. K. 0. K, ? 2 # ” Lot IV. 0. K. Looks about as bad as Lot I. Look worse. Still worse. i 2 H ” Pa “ om ~~ © ~ =~ ~ o- . ~— en o- ow - - * oo ~~ - vr = oo e 2 ° -~ . oo ~ e. - . - ° . 3 ~~ _— ae oo - a: e & " i — o- ro . ~ ‘ - . . a- Verbena. Lot I. Lot II. Lot III. Lot Iv. Sprayed on April 20 Leaves dried Same as Not quite 0. K. some. Lot I. as bad as Lot Il. *# 28 Looxs some No change. Looks much " worse. petter. May 4 No change. " " O. K. " Heliotrope. Sprayed on April 20 Looks some- 0O. K. .O..K. O. K. what sickly. Poor color. * 28 No change. " a " May 4 Improved " " " some. Coleus Verischafelteii, QOoleus Yellow Verischafelteii, Achyranthes Lindii, Geranium, and Primula were also treated put with no change showing in any of the plants. fFfhis table is somewhat more satisfactory. The unsprayed Cinneraria evi- dently suffering from some outside influence. Experiment III. With this experinent fiom lots of six varisties each were sprayed with Zenoleum of three strengths five times. Lot I with a solution of one part to 20 of water. " TT Lu @ # @ ” | 8 40 @ ft "TIL i a a a 2 we # 60 ® 8 * IV was not sprayed at all. It was noted that the plants in Lot III of the Stock, Cinneraria, Beronia, and Ageratum had been more or less affect- ed so two more lots of these were secured and sprayed with a solution of one part to 80 of water and Lot VI with one part to 100 of water. "% o. er eo vd Geraniun. Sprayed on April 6 * Js " gO s 628 May 4 Achyranthe Emersonii. Sprayed on April 6 e 183 # 320 o 28 May 4 Stock. Sprayed on Lot I. Lot GO. Zs 0. Has very " little good ..- color. Leaves start-" ing to dry up. Much worse. " Many leaves " falling off. Oy Ka o; " n v u w w " bi] April 6 Bottom leaves Vex yellowish. lea " 18 #$=Little worse, Nea flowers wilt- of ed some. lea yel # 20 Much worse. Lod not as 2 628 No change. No May 4 "% =e es oS | 3 Begonia. Sprayed on April 6 " 18 " 20 " 2S May 4. Ageratum. Sprayed on April 6 u 13 a 620 " 628 May 4 Cinneraria. Sprayed on April 6 * 13 8 20 n 28 May 4 Lot I. Lot Ii Top of plant Not q and tips of as ba leaves black.Lot I Most of Plants plant turn- ed bad ing black. Leaves and Leaves tips of tips f pranches fali- of ing off. Dead. All la dead a tips. --- Plant Tips of plant Wilte wilted and tips. dried up some. Much worse. Tips wW. and dr some. Plants wilt- Much wi ed. Dead. Still |) --- Dead. Tips of Tips o leaves dried leaves some. very 1} Leaves worse ,Leaves flowers more. dried some. Worse. Leaves ly wil Bad. Whole wilted Dead. Almost " " —_ w. « - ~ = . ' 5 + . ‘ 1 . - a e 1 ‘ « 1 ' ? ve _ i e ’ : 1 . ! . . ’ 1 e e . , : e . , . » e t ' » . am . 1. . ‘ » ~ t ’ ’ . e ‘ e 8 ® in \ . 9 - ° ‘ - . e ’ ° 1 e , ‘ ° ® . . . . - ‘ ~ > - - “ ‘ -—_ -- . - - a we .- e . e ° e ~~ os ~ or 3 = -* . o- aa ~ - - ; / .- ™ -— yy I 4 - e 4 . Experiment VI. This experiment was the spraying of the following shrubs and trees with a soft water solution of copper sulphate strength 11-1000 and Zenoleym 1-60 on April 20th, 28th, and May 4th. Hard Maple. Soft Maple. Sycamore. White Pine. Lilac. Cork Him. Arbor Vitae. Honey Suckle. Norway Spruce. Box Elder. Buffalo Currant. Sumac. Golden Hicer. Ampelopsis Veitechnii. Virginia Oreeper. No effect was noticed from the copper sulphats sol.tion but the Zenoleum Killed the leaves on the Ampelopsis Veitenii and the Virginia Creeper. At this same time I sprayed the peach, pear, plum, apple and cherry with this same solution of Zenoleum and with a copper sulphate solution of twics the strength as used on the other trees, that is a solution 1 to 5°°. Here too, there was no effect except in the case of the pear. Here the leaves were badly injured especially the smaller ones. The older ones dried up in spots but were less seriously injured. Experiment V. This experiment consisted in spraying strawberries, gooseberries, blackberries, raspberries, currants, potatoes, peas, beans, lettuce, cucumbers, and radishes with copier sulphate 1-1000 and Zenoleum 1-60. The copper sulphate did not affect any of the plants but the Zenolewm affected the lettuce, cucumbers, peas, and beans in order named. All re- covered however and there was no apparent difference exceptins these plants wore somewhat later in maturing than those not sprayed. Experiment VI. in this experiment I endeavored to find the relative values of Bordeaux Mixture and Copper Sulphate as preventives of Anthracnose, Apple Scab, Pear Leaf Blight, and Rust on Carnations and Strawberries by spraying five times (on June 23, July 8, 9, 13, 21, ) with a soft water solution of copper sulphate 1-600 and with Bordeaux Mixture. The young shoots of Cuthbert Raspberries were sprayed for anthracnose but as so little anthracnose showed itself on either the sprayed or unsprayed plants no conclusion could be drawn . Pears were sprayed in a like manner for Pear Leaf Blight. It was found that the Copper Sulphate was injuring the foliage to such an extent that it would be impracticable to use it longer. Believing that possibly some mistake had been made Peas, Apples, Flums, and Chorries were sprayed with solution 1-600 and 1-1200. These were sprayed but twice put the sane injurious effect was noticed on the peas sprayed with the so- lution 1-600, while those sprayed with the 1-1200 solution were not affected at all. The other fruits were not hurt in the least by this spraying. No leaf blight has shown it- self on any of the trees sprayed or unsprayed. A Famense apple tree was sprayed in a similar manner and the results were very marked. The Copper Sulphate solution diminished the number of cases of scab very much, also the severoness with which it attacked the apple. The Bordeaux Mixtivte was even more beneficial than the Copper Sulvhate. It is safe to say that it diminished the o- ‘ number of scai’y apples at least one-half. It also made the sCab very much weaker than those where there was no sprevinge done. Two varieties of strawberriss (Pawnee and Swindle) were sprayed in a similar manner for the fungus Sphaerothica. Here the results were very apparent indeed, the sprayed planis in many cases being almost free from the fungus. The Copper Sulphate seemed to be somewhat superior to the Bordeaux Mix- ture in this experiment as those sprayed with Copper Sulphate geemed to be somewhat freer from the fungus. Spraying showed a decided improvement in the amount of rust on carnations. The Copper Sulphate was fully as good here as was the Bordeaux Mixture. It is thus shown that the Copper Sulphate is of consid- erable value for spraying apples for scab, of equal value with Bordeaux liixture on carnations, anc fully as valuable, if not more so, than Bordeaux liixture on strawberries. Experiment VIL. This experiment consisted in spraying different plants five times at intervals of about one week to see if a solu- tion of Zenoleum would kill various insect pests. By a pre- vious experiment it had been found that Zenoleum could not be safely used on plants stronger than one part to sixty of water, so this strength was used. Begonias were sprayed for the scaly bocaniu: hesperidum; Crotons for the Mealy Bug (Dactlopius), Red Spider, Thrip, and the fungus Pumafo-vagans; a Sasso Palm for the soalf feceniun olea; a Spiral Pine for tho funrus FPumago-varans; Chrysantheums for Black Aphis; c’ Cactus for the seaxle (Aspidiotus cacti); and an apple tree for the scale known as Mitalispis pomoriun. It was shown vory conclusively that this solution wiil not Kill the Fumago-vagans fungus, the mealy bug, red spider, and black aphnis. It did however kill the thrip and the hoc- anium Olea scale, and pfreatly reduced tiie scale on the cactus and apple. However it seems to be impracticable for those two scales for it was not effectual enourh to compensate for the time and expense of spraying. ee - ew ee - ATE UN Jil “tii 3 12 TY LIBRARIES il WT 1723