Bactericera cockerelli

Bactericera cockerelli, also known as the potato psyllid, is a potato/tomato psyllid native to southern North America. As its name suggests, it is commonly found on potato and tomato crops, where feeding of the nymphs causes a condition called psyllid yellows, presumed to be the result of a toxin.

The pest has caused significant loss in potato yields during periods of major population increase. Maximum potato yield loss appears to be related to infestations occurring early in the growing season, or on crops with a significant leaf canopy by summer. The psyllids are not heat tolerant and it is thought they survive summer temperatures in crops with sufficient leaf canopy through summer to offer shade.

The nymphs are very small and inconspicuous, feeding on the underside of leaves. Both nymphs and adults feed in the phloem.

The host range is reputed to be very wide, with many species from up to 20 genera recorded. Breeding hosts are generally recognised as being restricted primarily to Solanaceae, including important crop and common weed species, and a few species of Convolvulaceae, including bindweed and sweet potato.

Zebra chip is a recently diagnosed disease of potatoes associated with psyllid infestation and caused by species of the gram-negative bacterium, Candidatus Liberibacter. The tubers frequently have discolouration which becomes more clear during frying of chips. This disease causes very significant losses to farmers when it occurs as the potatoes are not suitable for making into chips or fries.

Researchers at the Agricultural Research Service (ARS) are searching for better methods to control the potato pest. Pesticides are usually used to control the potato psyllid population, however, it is difficult to predict the movement and migration of the psyllid in order to prevent outbreaks. ARS researchers are trying to isolate the compound that female psyllid excrete to attract males. They will then synthesize the compound and place it on tapes around potato farms in order to attract males. Attracting the males will indicate to potato farmers that the insects are colonizing their fields and farmers can then plan pesticide treatments as needed. The goal of this research is to develop a psyllid-specific monitoring tool to allow farmers to use pesticides only when they are needed. [2]