ABSTRACTCHEMICAL ECOLOGY OF WILD SOLANUM SPP AND THEIR INTERACTION WITH THE COLORADO POTATO BEETLEByMonica J. HufnagelTo date the Colorado potato beetle (CPB) continues to be an important threat for potato growers world-wide. Wild potatoes are a source of a genetic diversity encoding properties such as resistance to pests, which may provide sustainable alternatives to the use of pesticides. First objective was to investigate the effects of single accessions of three wild Solanum species on the growth and development of CPB compared to effects of the cultivated S. tuberosum cv. Atlantic. Larvae consumed significantly less foliage of S. immite and S. pinnatisectum compared to the cultivated potato. Larvae were unable to complete their development on S. immite and significantly fewer completed their development on S. pinnatisectum compared to the cultivated potato. No significant differences were observed between S. chacoense and S. tuberosum. Surprisingly, females laid the greatest amount of eggs on S. immite, while there were no significant differences among the other species in oviposition preference. My second objective was to analyze chemical defenses in the potato species. S. immite and S. pinnatisectum, the least preferred by CPB for larval feeding and larval had two volatiles, limonene and terpinolene, which comprised about 90% of the headspace, suggesting that they could be involved in resistance to CPB. There was no significant difference in content of the glycoalkaloid solanine between the least (S. immite) and most preferred (S. tuberosum) potato species by the CPB. No acyl sugars were found by leaf dip analysis in any of the potato species. This same analysis provided information about glycoalkaloid content with solanine and chaconine present only in S. tuberosum, S. chacoense and S. immite and tomatine only found in S. pinnatisectum.
Read
