This study explored the biology of raspberry crown borer, Pennisetia marginata (Harris) (Lepidoptera: Sesiidae), in Arkansas and the optimum timing for insecticide and nematode applications. The duration of P. marginata's life cycle was observed to be 1 yr in Arkansas. Insecticide trials revealed that bifenthrin, chlorpyrifos, imidacloprid, metaflumizone, and metofluthrin efficacy were comparable with that of azinphosmethyl, the only labeled insecticide for P. marginata in brambles until 2005. Applications on 23 October 2003 for plots treated with bifenthrin, chlorpyrifos, and azinphosmethyl resulted in >88% reduction in larvae per crown. Applications on 3 November 2004 of metaflumizone, metofluthrin, and bifenthrin resulted in >89% reduction in larvae per crown. Applications on 7 April 2005 for metofluthrin, imidacloprid, bifenthrin, metaflumizone, and benzoylphenyl urea resulted in >64% reduction in the number of larvae per crown. Applications on 6 May 2004 did not reduce larval numbers. The optimum timing for treatments was found to be between October and early April, before the larvae tunneled into the crowns of plants. Applying bifenthrin with as little as 468 liters water/ha (50 gal/acre) was found to be as effective against larvae as higher volumes of spray. Nematode applications were less successful than insecticides. Nematode applications of Steinernemafeltiae, Steinernema carpocapsae, and Heterorhabditis bacteriophora reduced larvae counts per plant by 46, 53, and 33%, respectively.
Grape scale, Diaspidiotus uvae (Comstock), is a pest of grapes, Vitus spp., in the south-central United States. This study compared Julian days and cumulative degree-days (DD at base 10°C accumulated after 1 April) to grape scale biology and control in Arkansas. On the average, first generation crawlers began emerging 14 May (274 DD) and peaked on 20 May (356 DD). First generation winged males began emerging on 26 June (794 DD) and peaked 13 July (1,108 DD). Second generation crawlers began emerging on 20 July (1,166 DD) and peaked on 12 August (1,549 DD). Second generation wingless males began emerging on 31 August (1,857 DD) and peaked on 18 September (2,026 DD). Relative to untreated vines, vines treated with chlorpyrifos at bud swell (early April) or as late as early May (near grape bloom) realized at least an eight-fold reduction in the number of crawlers and adult males per sticky tape trap. Vines receiving the second application near grape bloom had significantly fewer crawlers in May, August and September than vines sprayed once in late April. A chlorpyrifos treatment in early April provided at least a 30-d lethal residual on grape against grape scale crawlers that emerged during May.
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