Sustainable Pest Management

There exists a lack of control efficacy information to enable decision-making about which organic insecticide product works best for a given insect pest. Here we summarize results of 153 field trials on the control efficacy of common active ingredients in organic insecticides against groups of the most difficult to control insect pests. The performance of organic products Entrust (spinosad), Azera (pyrethrin and azadirachtin), PyGanic (pyrethrin) and Neemix (azadirachtin) varied widely among pest groups, as well as among pest species within a group, providing an overall reduction in pest infestations by 73.9%, 61.7%, 48.6% and 46.1%, respectively.

August IPM insect scouting tips on soybean, field corn, and sorghum.

Entomopathogens are bacteria, fungi, protozoans or viruses that can infect and subsequently cause disease in insects and other arthropods. They can indirectly impact cropping systems by serving as naturally suppressors of insect and mite pests. When there are epizootic outbreaks, entomopathogens are capable of causing rapid declines in large populations of their arthropod hosts. Many of these naturally occurring pathogens have been formulated and commercialized as insecticides.

Grape Flea beetles, Altica spp. (Coleoptera: Chrysomelidae), are small (4-5 mm), oval shaped, metallic blue-purple beetles that jump when disturbed.

The previous “Timely Viticulture” addressed some basic information on MALB and this message will concentrate on management tactics. Some sections of this message were intentionally repeated, but there is new information throughout.

The brown marmorated stink bug (BMSB) has become a state-wide problem in Maryland vineyards, and its range and damage is increasing. The full impact on vineyards and wine quality potential of this newly introduced pest is unclear. TimelyVit — Part 1 — was created to give growers background on the pest and this TimelyVit will address some management options. Regretfully, it must be stressed that this is a new “introduced” pest and very little is currently known of its management, thresholds for management.

The brown marmorated stink bug (BMSB) has been a localized problem in Maryland thus far but that may be expected to change in the future. The full impact on vineyards and wine quality potential of this newly introduced pest is unclear. This Timely Viticulture was created to give growers some background on the pest. The next TimelyVit will address some potential management options. Regretfully, it must be stressed from the beginning that this is a new “introduced” pest and very little is currently known of its biology, but it is evident that it has the potential to be a very significant pest.

Soybean: Scout for the usual defoliators, including bean leaf beetle, Japanese beetle, and caterpillars. The treatment threshold is 15-20% defoliation for bloom to pod fill. Note that defoliation percentages should be based on the entire soybean plant or canopy, not just the top leaves or worst leaves. University of Nebraska Extension has a nice guide for defoliating insects in soybeans (https://croptechcafe.org/defoliating-insects-in-soybeans-thresholds-training-and-tools/). Adult Dectes Stem Borer will be emerging over the next several weeks. Chemical control is not recommended since it would require multiple applications to reduce larval infestations, which is not economical. However, if a high number of adults are found, harvesting that field as soon as it matures will reduce losses associated with lodged plants.

I have seen and have gotten reports of stinkbug damage in tomatoes over the past few days. Stinkbug feeding damage is called cloudy spot in tomato fruit (fig. 1). It occurs when the adult or immature stinkbug puts its needle- like mouth part into the fruit and removes material from a large number of cells.

Soybeans: Continue scouting for corn earworm, stink bugs, and soybean looper in double-crop fields. Defoliation thresholds at R5 are 15% and between 20 and 30% at R6. Corn earworm pheromone trapping information for Maryland can be found at https://extension.umd.edu/resource/corn-earworm-pheromone-trapping. NC State Extension has a good CEW threshold calculator can be used to help decide if it is worth treating: https://www.ces.ncsu.edu/wp-content/uploads/2017/08/CEW-calculator-v0.006.html. Stink bug thresholds are 5 bugs per 15 sweeps until the soybeans reach the R7 stage, after which treatment for stink bugs is not necessary.