Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 31, 2009
Publication Date: December 1, 2009
Repository URL: http://hdl.handle.net/10113/37605
Citation: Avery, P.B., Hunter, W.B., Hall, D.G., Jackson, M.A., Powell, C.A., Rogers, M.E. 2009. Diaphorina citri (Hemiptera: Psyllidae) infection and dissemination of the entomopathogenic fungus Isaria fumosorosea (Hypocreales: Cordycipitaceae) under laboratory conditions. Florida Entomologist. 92(4):608-618. Interpretive Summary: A method was developed to increase efficacy and reduce grower costs when using the biological control fungal agent Paecilomyces fumosoroseus blastospores to manage adult Asian citrus psyllids. We studied the efficacy of an autodissemination system on a small scale for the potential to reduce the need to spray entire groves by holding adult psyllids in close proximity to yellow tags treated with the fungus. Adult psyllids were attracted to the yellow tags and became infected. Good infection rates of adults were achieved. Yellow plastic tags inoculated with the fungus and deployed in citrus holds potential as an autodissemination system for spreading the disease and killing psyllids and, as such, may be a cost effective alternative to area-wide sprays.
Technical Abstract: A method was developed to increase efficacy and reduce grower costs when using the biological control fungal agent Paecilomyces fumosoroseus blastospores (Deuteromycotina: Hyphomycetes) to infect adult Asian citrus psyllids, Diaphorina citri (Psyllidae: Hemiptera). We analyzed the efficacy of this ‘Autodissemination system’ on a small scale for the potential to reduce the need to spray entire groves by using a focused delivery of either sprayed treated yellow tags or citrus leaves. Efficacy of treated tags versus leaves were compared and horizontal transmission of the fungus by the movement of the psyllid among leaves were assessed using a detached leaf bioassay technique in Petri dishes at 25oC under a 16 hour photophase. One adult psyllid was released into each dish with either 4 leaf sections or 3 leaf sections and a yellow plastic tag on moistened filter paper. Treatments were citrus leaf sections or a yellow tag of similar size (100 - 125 mm2) sprayed with P. fumosoroseus. Proportions of all leaf sections were sprayed as follows: 25%, 50%, 75%, 100% compared to a yellow tag. Four leaf sections sprayed with distilled water served as the control. A Fungal Development Index was used to determine the rate of infection once the insect had died and showed signs of mycosis. The yellow tag treatment was equally effective as the other leaf treatments in the rate of infection and induced infection more rapidly in psyllids when compared to the 25% leaf section treatment. Adults began to mycose at approximately 4-5 days post-release. As the inoculum increased for all leaf section treatments, the infection rate also increased. For all fungal treatments there was also 100% horizontal transmission of P. fumosoroseus spores to all non-treated leaf sections. The potential of inoculated yellow plastic tags as an autodissemination technique for managing psyllid populations in citrus groves may reduce costs to growers.