Screening Sticky Cards as a Simple Method for Improving Efficiency of Diaphorina citri (Hemiptera: Liviidae) Monitoring and Reducing Nontarget Organisms.

Abstract

Management of Diaphorina citri Kuwayama (Hemiptera: Liviidae) populations is one of the major strategies for reducing the spread and incidence of huanglongbing (HLB). HLB is putatively caused by Candidatus Liberibacter spp. (Rhizobiales: Phyllopbacteriaceae) that are transmitted to citrus by psyllid vectors. Diaphorina citri population monitoring is done to detect its presence and inform on management decisions. Various methods are used for detecting and estimating D. citri densities but trapping with yellow or lime-green sticky cards has proven to be the most effective method. These sticky cards rely on the color preference of adult D. citri, but many flying organisms are attracted to the same color spectrum as psyllids. Hence, in field situations, sticky traps are hampered by large numbers of bycatches of nontarget organisms and debris. Here, we described a method using a mesh laid on the surface of traps as a sift to catch mainly psyllids, while reducing bycatches. By filtering D. citri through this mesh, they can be counted more rapidly and accurately. Although mesh-covered traps captured 5-15% less D. citri relative to uncovered ACP traps, both types of traps statistically agreed on D. citri detection and population densities. The effectiveness of mesh-covered traps did not vary with season. In addition, mesh-covered traps eliminated >90% of nontarget organisms and allowed for quicker enumeration of D. citri. We expect this method will become an important component of redesigning integrated pest management programs in citrus groves by reducing unintended impacts of beneficial arthropods during large scale D. citri monitoring.