Chapter 7 - Psyllids: Biology, Ecology, and Management

Abstract

The tomato psyllid (Bactericera cockerelli) (Šulc) (Hemiptera: Triozidae) is a pest on solanaceous vegetable crops. The psyllid was recognized as an occasional pest in western North America nearly a century ago. Historically, the psyllid was associated with psyllid yellows, a disease of unknown origin associated with feeding by nymphs. In the last decade, tomato psyllids have been identified as the vector of Candidatus Liberibacter solanacearum (Cls) a bacterial pathogen that causes zebra chip disease in potato and vein greening disease in tomatoes. Vein greening results in a variety of symptoms that can include reduced fruit set and death in extreme cases. The discovery of Cls has led to an increasing body of research on the management and biology of tomato psyllids. It is now recognized that there are at least three haplotypes of the psyllid associated with various geographic regions. Management of the psyllid is complicated both by the various haplotypes and by the presence or absence of Cls. There is currently only one sampling plan for management of tomato psyllids on tomatoes. That plan is designed for use in California with the western psyllid haplotype, and it does not account for Cls. Presently, there are no varieties of tomato resistant to the psyllid or Cls. Management of potato psyllid is currently based on multiple calendar-based applications of insecticides. Less focus has been placed on management in tomatoes versus potatoes, but there is a small list of materials that are effective in controlling the insect. Resistance is already developing in some regions for certain materials. The tomato psyllid has numerous natural enemies which have been identified in California. Unfortunately, most of the identified enemies are generalists and there are none that are effective for biological control when Cls is present. Further research will be required to refine management techniques for these increasingly important pests.