Field application of Hirsutella citriformis Speare strains against Diaphorina citri Kuwayama (Hemiptera: Liviidae) adults

The Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Liviidae) is the most serious threat to citrus crops worldwide. Several entomopathogenic fungi species have been reported to infect and kill D. citri in different geographical regions However, Hirsutella citriformis Speare (Hypocreales: Ophiocordycipitaceae) is the only fungus reported to cause natural epizootics on this insect. Conidial infectivity of five H. citriformis strains was evaluated in a field assay against D. citri adults. Three bioassays were performed in a Persian lime and one in a Mexican lemon orchard in Chiapas, Campeche, Quintana Roo, and Colima Mexican states. H. citriformis conidia application consisted of 15 flush shoots for each treatment, where insect adults were infesting, whereas on the untreated control, we applied sterile potato dextrose broth with yeast extract. After application, treated branches areas remained bagged for 21 d. All strains showed pathogenicity against D. citri. CHE-CNRCB 339 (74.14% mortality) and INIFAP-Hir-2 (68.25% mortality) strains caused the highest mortality percentages. Among dead insects, the highest mycosis percentage was recorded on psyllids treated with the CHE-CNRCB 339 strain (74.14%).