Elicitation of plant defenses as an alternative to pesticides for control of colorado potato beetle and late blight

This project is a collaboration with Jennifer Thaler (Entomology) and Bill Fry (Plant Pathology) funded by Cornell Hatch funds.  Our goal is to reduce reliance on pesticides and to manage the plant’s own defenses to control pests. Potato as a crop receives a disproportionate share of pesticides because of two devastating pests: Colorado Potato Beetle, and Phytophthora infestans, causing Late Blight. Now that we have the technology to manipulate induced resistance with natural plant hormones and synthetic activators of plant defense, potato is a key crop for which elicitors should be evaluated. The development of “jasmonate” and “salicylate” elicitors follows developments in plant physiology and molecular biology that have merged a mechanistic understanding of plants with the potential to control pests that eat them. The use of elicitors will allow the continued use of grower-preferred varieties, because no genetic transformation or breeding will be required. Elicitors may thus enhance resistance to both of these major pests.

Over the next three years, we will to study ways to manipulate natural plant resistance to control Colorado Potato Beetle and Late Blight, two of the most devastating pests of potatoes in New York.  We will employ the application of natural and synthetic plant hormones to potatoes in field plots to stimulate the plant’s natural resistance mechanisms.  Our primary goal is to assess the impact of various elicitors of plant resistance on colonization and damage by insects and pathogens, as well as biological control by native beneficial insects.  We intend to utilize knowledge about the natural seasonal development of pests on potato to enhance resistance to multiple pests and to maximize the compatibility of resistance and biological control.  We will measure both biochemical and gene expression responses of the plants to our application of elicitors in order to characterize the natural levels of plant immunity and how these correlate with patterns of attack in the field. 

Thus our specific objectives follow a three step progression: 1) How does application of natural and synthetic plant hormones to potatoes affect production of defenses compounds in leaves, gene expression in leaves, attack by insects and disease, control by beneficial insects?  This first objective will be conducted at a small scale (single potato plants) and the focus will be to test several elicitors and to obtain field patterns to the potential effects.  2) Can we scale these patterns up to larger field plots and hone our application of particularly effective elicitors to specific concentrations and seasonal timing so as to maximize effectiveness?  This objective focuses on narrowing the possibility of elicitors, addressing scale, both in terms of space and timing. 3) When applied to larger field plots, can we detect a yield benefit (both in terms of quality and quantity) of the elicitor treatments?  Are these effects apparent under a restrictive set of environmental conditions?  Here, our final objective seeks to address questions most relevant to growers by working on the level of variability and likelihood of success of the application of elicitors for crop yield.