Efficacy of an autodisseminator of an entomopathogenic fungus, Isaria fumosorosea, to suppress Asian citrus psyllid, Diaphorina citri, under greenhouse conditions

Authors: Patt, Joseph - Joe; CHOW, ANDREW - Texas A&M University; Meikle, William; GRACIA, CARLOS - Texas A&M University; Jackson, Mark; FLORES, DANIEL - Animal And Plant Health Inspection Service (APHIS); SETAMOU, MAMOUDOU - Texas A&M University; Dunlap, Christopher; AVERY, PASCO - University Of Florida; Hunter, Wayne; MAFRA-NETO, AGENOR - Isca Technologies, Inc; Adamczyk, John

Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/24/2015
Publication Date: 4/29/2015
Citation: Patt, J.M., Chow, A., Meikle, W.G., Gracia, C., Jackson, M.A., Flores, D., Setamou, M., Dunlap, C.A., Avery, P., Hunter, W.B., Mafra-Neto, A., Adamczyk Jr, J.J. 2015. Efficacy of an autodisseminator of an entomopathogenic fungus, Isaria fumosorosea, to suppress Asian citrus psyllid, Diaphorina citri, under greenhouse conditons. Biological Control. 88:37-45.

Interpretive Summary: The Asian citrus psyllid (ACP)transmits huanglongbing (HLB)(also known as citrus greening), the most devastating disease of citrus trees in the world today. Psyllids living in citrus trees growing in neighborhoods, parks, etc. can fly into commercial citrus orchards and spread HLB to those orchards. There is an urgent need for a biologically-based control system to suppress psyllid populations in residential citrus. This paper reports on pilot studies aimed at developing a dispenser to inoculate psyllids with the spores of a native pathogenic fungus that would kill infected psyllids. The idea is that these dispensers could be hung on backyard trees and be used to induce epidemics of the pathogen in local psyllid populations. The dispenser incorporates features, such as a series of parallel edges, to help retain psyllids and increase spore transfer. After being released in a greenhouse and exposed to the dispensers, an average of 55% of the psyllids became infected. Adult psyllids transferred spores from the dispensers to flightless immatures living on potted orange jasmine plants, with 27-35% of the immatures becoming infected. Adult production from immatures exposed to spore-carrying adults was reduced by 35%. Once dead, infected psyllids produced contagious spores that readily infected nearby individuals. These results confirmed that the concept of using a dispenser to infect Asian citrus psyllid is plausible, and that the basic design of the dispenser tested here was sound with respect to attracting, retaining, and infecting ACP.

Technical Abstract: The Asian citrus psyllid (ACP), transmits the causative agents of citrus greening disease or huanglongbing (HLB), the most devastating disease of citrus trees in the world today. ACP dwelling in noncommercial citrus (neighborhoods, commercial landscapes, etc.) can stymie area-wide management programs aimed at containing the spread of HLB in commercial citrus orchards. There is an urgent need to design a rapid biological control system to suppress ACP populations in noncommercial citrus that is effective, safe, and acceptable to regulatory agencies, homeowners and organic growers. This study reports on pilot studies aimed at developing an autodisseminator (‘dispenser’) for inoculating ACP with a native pathogenic fungus, Isaria fumosorosea (Ifr), and inducing epizootics of the pathogen in noncommercial citrus trees. Exposure of free-flying ACP to dispensers in a greenhouse resulted in an average of 55% of the psyllids becoming infected. Adult production from nymph colonies exposed to Ifr-carrying adults was reduced by 35%. These results confirmed that the concept of using an autodisseminator to infect ACP is plausible and that the basic design of the autodisseminator used here was sound with respect to attracting, retaining, and infecting ACP.