ARS | Publication request: Effects of Cucurbitacin on the Activity of Nucleopolyhedroviruses against Pickleworm Larvae

Submitted to: Journal of Agricultural and Urban Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 25, 2010
Publication Date: February 20, 2011
Citation: Jackson, D.M., Shepard, B.M., Shapiro, M., El Salamouny, S. 2009. Effects of Cucurbitacin on the Activity of Nucleopolyhedroviruses against Pickleworm Larvae. Journal of Agricultural and Urban Entomology. 26:95-106.

Interpretive Summary: Pickleworms are a major pest of cucumbers and summer squash in the eastern United States. Late-season crops are sprayed excessively with insecticides to control this pest and results are sometimes unsatisfactory. Thus, there is a need for new biologically-based control tactics, such as insect viruses, for control of pickleworms on cucurbits. We found that three naturally occurring viruses are moderately effective at killing pickleworm larvae in the laboratory, and that the effectiveness of these viruses could be enhanced with certain additives, including a feeding stimulant isolated from a wild bitter watermelon and marketed as Invite® EC (Florida Food Products). Low concentrations of Invite were attractive to young pickleworm larvae, which caused them to feed more effectively on virus-treated plants. Because enhanced feeding results in increased virus effectiveness, Invite may be useful as a spray additive for pest management of pickleworms in the field.

Technical Abstract: The cucurbitacin-containing feeding stimulant (Invite® EC) was attractive to second instar pickleworm larvae in the absence of a food source. Second instar pickleworm larvae also fed preferentially on cucumber fruits that were treated with a 1% (0.01X) solution of Invite EC. However, 1% Invite did not stimulate feeding in on artificial diet, squash leaves, or squash fruits. Concentrations of Invite as low as 0.001% were effective in increasing the efficacy of the velvetbean caterpillar, Anticarsia gemmatalis Hübner, multiply embedded nucleopolyhedrovirus (AgMNPV). A 1% Invite solution also increased the efficacy of the celery looper, Anagrapha falcifera (Kirby), multiply embedded NPV (AnfaMNPV) against second instar pickleworms.