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Title: Control of Liriomyza trifolii (Diptera: Agromyzidae) in cut flowers using Isaria fumosorosea (Hypocreales: Cordycipitaceae) alone and in combination with insecticides

Author
item WEKESA, VITALIS
item AVERY, PASCO - University Of Florida
item McKenzie, Cindy
item POWELL, CHUCK - University Of Florida
item OSBORNE, LANCE

Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/28/2010
Publication Date: 2/1/2011
Citation: Wekesa, V.W., Avery, P.B., McKenzie, C.L., Powell, C.L., Osborne, L. 2011. Control of Liriomyza trifolii (Diptera: Agromyzidae) in cut flowers using Isaria fumosorosea (Hypocreales: Cordycipitaceae) alone and in combination with insecticides. Journal of Entomological Science. 46(1): 80-84.

Interpretive Summary: Liriomyza trifolii (Burgess) readily infests greenhouses and their larvae feed on numerous crops worldwide including ornamentals and vegetable crops. Damage caused by larval mines significantly reduces photosynthetic capacity of the crops and causes leaf fall during heavy infestations. Apart from direct damage caused by larval feeding on leaf tissues, females may act as vectors for diseases during oviposition. New approaches for reliable control of leafminers are necessary, especially for the use of entomopathogens because of their potential compatibility with other control measures. This study compared the relative effectiveness of the fungus, Isaria fumosorosea for control of the leafminer applied alone and in combination with pesticides. In gerbera, the entomopathogenic fungus performed as well as standard pesticides in reducing leafminer populations whether applied alone or in combination with a pesticide. Results demonstrated that leafminer control may not need a joint application of this fungus with a pesticide which can aide in reducing pesticide resistant leafminer populations while cutting down on production costs.

Technical Abstract: The generalist entomopathogenic fungus, Isaria fumosorosea (Wize) Brown and Smith (Hypocreales: Cordycipitaceae) strain Apopka-97 has exhibited significant potential as a biological control agent of several important pests both in the field and greenhouse. Although this fungus has never been tested against, Liriomyza trifolii (Burgess), its efficacy against other polyphagous pests and compatibility with other control measures makes it a good choice for control of leaf miner flies. In this study, the relative effectiveness of the fungus, I. fumosorosea (PFR 97) was compared to pesticides for the management of L. trifolii populations in gerbera daisies and sunflower. The fungus was applied alone or in combination with pesticides and the number of flies captured on yellow sticky cards as well as the leaf mines were compared with the control blocks for four weeks. Very low numbers of adults were trapped in sunflower compared to the gerbera daisies with all treatments being similar. In gerbera, the number of flies significantly decreased with time in all the treatments, an indication that the population declined as a result of treatment application in this crop. However, there were no differences in the abundance of flies from 7 - 28 days post treatment between treatments, suggesting that PFR 97 is as effective as the pesticides. Results demonstrated that leafminer control may not need joint application of this fungus with the pesticides and can help in breaking up resistant populations while cutting down on production costs.