Developing and disseminating potato virus management strategies for northeastern growers
There are economic and environmental imperatives for the development of biological disease control strategies for Potato Virus Y (PVY). PVY is an economically important crop disease that reduces yield and, in the worst cases, causes crop failure in many solanaceous crops, including potatoes, tomatoes, tobacco, peppers, and eggplants. PVY presents a daunting management challenge, because it is transmitted rapidly by a vast array of aphid species and infected plants can be difficult to identify in the field. Current strategies, such as pesticide applications and removal of infected plants from the field, are not effective, needlessly increasing chemical inputs at both an economic and environmental cost.
The goal of this project is to develop and disseminate a biological disease control strategy for potato growers that minimizes PVY spread by enhancing naturally occurring aphid natural enemy populations. To begin this work, nineteen farms were surveyed for aphids, aphid natural enemies, and PVY, and the landscape composition of the area surrounding the farm was analyzed using ArcGIS software (Figure 2). Though analysis is not complete, there is a significant direct relationship between the amount of agricultural land surrounding a farm and the end of season PVY prevalence; the more agriculture in the area, the more PVY there is, given an introduction of the virus in the potato seed tubers (Figure 4). The insect community across the region is extremely diverse, including at least 54 species of aphids, and the aphid natural enemy assemblage includes at least three species of ladybugs, as well as lacewings, and pirate bugs.
1) Survey the main aphid vector species, common natural enemies of aphids, and the distribution and spread of PVY on small farms across several counties in New York State: I monitored the presence and spread of PVY by sampling plant tissue in potatoes and all other solanaceous crops grown on nineteen farms using an enzyme-linked immunosorbent assay (ELISA) (Figure 1). I trapped and surveyed aphid natural enemy and aphid populations in potato fields throughout the growing season. I have conducted this survey for one field season and will continue it for another season.
2) Evaluate the influence of landscape-level effects: Using GIS software, I analyzed the landscape composition of the area surrounding the potato fields at two scales: within a 0.5km radius, and within a 5km radius. Land use was quantified as %agricultrual, %forested, %developed, etc. (Figure 2). I will test whether or not the complexity of the landscape surrounding the potato field affects aphid natural enemy populations, aphid populations, and PVY prevalence among all solanaceous crops, in addition to the completed analysis on the effect of landscape on PVY prevalence within potato fields (Figures 3 and 4).
3) Evaluate the influence of aphid community composition on PVY prevalence and spread: In field experiments scheduled for the summer of 2014, I will examine the impact of aphid species diversity and evenness on PVY prevalence and spread, focusing on the major vector species found in the surveys.
4) Evaluate the effect of natural enemy community composition on PVY prevalence and spread: In field experiments scheduled for the summer of 2014, I will test the effect of aphid natural enemy diversity and abundance on PVY prevalence and spread by introducing the most commonly found natural enemies to treatments developed in Objective 3. This work will allow me to determine the most effective naturally occurring biological control agents.
5) Disseminating disease control management strategies: Analyzed cumulatively, the data from Objectives 1-4 will result in management recommendations for growers to maximize disease control on their farms through appropriate farm layout and potato growing practices. I will disseminate this and related information through multiple media channels. I have been invited to submit an article to a regional grower-oriented publication.
Over the past year, I have established a landscape level project, setting up research sites at nineteen farms. I analyzed landscape composition surrounding the farms prior to the field season, to ensure that the sites included an appropriate range of agricultural intensification. This summer I conducted a survey of aphids, aphid natural enemies, and PVY at these sites. Following this field season, I have analyzed approximately 3100 plant tissue samples using enzyme-linked immunosorbent assay (ELISA). I have also received training in aphid species identification from Dr. David Voeghtlin, an aphid systematist at the University of Illinois, which has enabled me to sort the first 400 trap samples for aphids and aphid natural enemies.
In the future, I need to finish sorting the 2012 trap samples (approximately another 200 samples), replicate the survey for another season, and conduct a series of field experiments analyzing the impact of aphid and aphid natural enemy diversity on PVY prevalence and spread, which should occur in the summer of 2014.
My project has proceeded as expected and I have learned a great deal over the course of the last year. I have gained project management and mentorship experience and learned several research techniques necessary for the project, which will allow me to be more efficient during the next field season.
Impacts and Contributions/Outcomes
The data I have collected so far will provide useful information about the most common PVY aphid vectors and aphid natural enemy species, as well as the prevalence of PVY on small-scale farms across the Finger Lakes region. This will allow for more effective estimation of the risk of in-season disease spread. Further work will yield information that should inform farm planning. Identifying a biological control agent that suppresses the major aphid vectors would reduce dependence on ineffective control measures, such as pesticides, increasing overall sustainability.
This fall, I began mentoring an undergraduate student who is contributing to the landscape level project and I am preparing to disseminate my project results both through factsheets to participating growers and in articles in grower-oriented publications.
Senior Extension Associate
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