UC Riverside

The potato/tomato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Triozidae) is a major pest of solanaceous crops. This pest causes yield loss by direct feeding on crop plants and by transmitting a bacterial pathogen known as Candidatus Liberibacter psyllaurous (a. k. a. Ca. L. solanacearum). The goal of my research is to improve pest management against this pest in potatoes by integrating sampling, insecticides, use of resistant varieties, and biological control.

Sampling plans are essential part of integrated pest management (IPM). From my research on potatoes, I determined the most efficient sampling unit, and that this pest has an aggregated distribution in the field. Binomial sequential sampling plans were developed for the potato psyllid. Current pest management practices in the USA rely on the intensive use of broad-spectrum insecticides to control the potato psyllid to lower disease incidences and increase yields. I evaluated five insecticides in the laboratory. All insecticides tested significantly reduced probing durations and increased the amount of time adult psyllids spent off the leaflets compared to untreated controls suggesting that these chemicals may be deterrents to feeding as well as repellents. Additionally, I further tested the effects of imidacloprid on potato psyllid feeding behavior using a direct current electrical penetration graph technique.

Host plant resistance can be an integral component of an integrated approach for the management of arthropod pests. I tested the effects of potato germplasm from 22 genotypes on adult potato psyllid behavioral responses for possible antixenosis and determined if specific breeding clones or varieties can decrease transmission of Ca. L. psyllaurous. Another assessment that should be made in an IPM program is the potential role of natural enemies in controlling pests. Through two years of field studies (2009-2010) at four different sites and laboratory feeding tests, I have identified Orius tristicolor (White) (Hemiptera: Anthocoridae), Geocoris pallens Stal (Hemiptera: Geocoridae), Hippodamia convergens Guerin-Meneville (Coleoptera: Coccinellidae), and the parasitoid Tamarixia triozae (Burks) (Hymenoptera: Eulophidae) as key natural enemies of the potato psyllid in southern California potatoes, tomatoes, and bell peppers. I discuss how this information can be used in an integrated pest management program for the potato psyllid.