An Evaluation of the Residual Activity of Traditional, Safe, and Biological Insecticides Against the Gypsy Moth    (View PDF)

Ralph E. Webb, Randy Peiffer, Roger W. Fuester, Kevin W. Thorpe, Louis Calabrese, and Joseph M. McLaughlin

Abstract: We evaluated the direct and the residual efficacy of selected traditional, safer, and biological insecticides that are either registered or are candidates for registration for use by arborists and nurserymen in Integrated Pest Management (IPM) programs for gypsy moth (Lymantria dispar} management in urban settings. The study compared 5 biological insecticide treatments (1 Bacillus thuringiensis[Bf] and 4 gypsy moth nuclear polyhedrosis virus [NPV] treatments) and 2 reduced-risk insecticides (neem and tebufenozide) against 2 commonly used standard insecticides (diflubenzuron and cyfluthrin). Significant details pertaining to the use of the specific control materials were clarified in support of a decision matrix around which an IPM system can be formulated for use by arborists and nurserymen. The standard insecticides, cyfluthrin and diflubenzuron, and the ecdysone agonist tebufenozide, demonstrated excellent activity against all instars in both a 1 - hour residue study and a 35-day residue study, Bt was clearly more effective against second instar larvae than against fourth instar larvae and lost significant activity against the gypsy moth after 7 days. The efficacy of the neem product was similar to that of Bt in that it controlled younger instars better than it did older instars. Although its speed of action was slower than that of Bt, it remained highly active against gypsy moth 21 days after treatment. NPV without the activity enhancer Blankophor BBH gave significant levels of control for all 4 larval instars fed on 1 -hour residues, although mortality was higher for younger instars than for older instars. Residual effectiveness was significantly reduced after 1 day. The addition of Blankophor BBH to the NPV tank mix led to improved kill in the 1-hour study and to vastly improved residual activity (up to 35 days).

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https://doi.org/10.48044/jauf.1998.035