Spider mites are burning soybean fields

Twospotted spider mites can become serious pests of soybean whenever hot, dry weather persists. We have confirmed reports from Lee and Wapello counties in southeastern Iowa where fields have been sprayed because spider mites are burning the leaves and causing plant defoliation. The twospotted spider mite is named for the two dark spots on the sides of the abdomen, which are digested food visible through the insect\u27s translucent body. Three or four spots may be apparent and are most prominent on adult mites

Integrated Pest Management—Stalk Borer Ecology and Pest Management Options in Corn and Soybean

Stalk borers can heavily infest crops that are adjacent to grass terraces, fence lines, or grass waterways and cornfields. Cultural and chemical management techniques are discussed.https://lib.dr.iastate.edu/extension_ag_pubs/1182/thumbnail.jp

Soybean aphid scouting and management

Management activities for most soybean insect pests consist of scouting, use of thresholds, insecticide applications when necessary, and prevention through cultural activities. Probably the most practical scouting method for soybean producers is to take soybean aphid counts on leaves. This method is useful for pest detection when insect densities are low

Soybean aphid biology

The soybean aphid was first reported in Iowa in 2000. It has survived the winter and colonies are now being found south of Decorah in Winneshiek County in northeastern Iowa. Aphid colonies were very small, often less than 10 aphids on a plant, and they were clustered on the underside of the newly developing trifoliate leaves. The aphids were difficult to find and checking 20 plants at random in several fields was not a large enough sample to detect these small population

Expect lots of bean leaf beetles in 2000

If you read the bean leaf beetle prediction in the May 1 ICM newsletter, you\u27ll know that winter mortality of this soybean pest is expected to be at a 12-year low. The result will be that we should have more bean leaf beetles this spring than during an average year. In fact, our predictions, based on summer population increases during the last several years coupled with the mild winter, are for the populations to be very large. Sweep samples taken from alfalfa fields in Ames on May 2 indicate that the beetles are extremely abundant; they should move to soybeans as soon as the plants germinate

Biology and Management of Bean Leaf Beetle in Soybean

The bean leaf beetle, Cerotoma trifurcata (Forster), is a widespread pest of soybean in the major crop production areas of the U.S. It has been a significant problem in the South but, until the last decade, was an infrequent problem in the Midwest. During earlier times, the major concern was early season invasion of soybean fields and localized problems of seedling defoliation. In the 1980\u27s, however, grower reports of pod feeding were received, and these have increased significantly until the present. Indeed, today the bean leaf beetle has become the most consistently important insect problem on soybean in our region. The purpose of this presentation is to update specialists on the soybean and outline a basic integrated pest management (IPM) system for the species in Iowa. To accomplish this, we will discuss foundation elements of IPM, including identification and biology, sampling for adults and pod injury, and economic thresholds. We will conclude by describing both preventive and curative tactics that can be employed to reduce losses from this growing pest problem

Potato Leafhopper-Resistant Alfalfa: Yield Advantages and New Pest Management Guidelines

In 1997 several companies released new potato leafhopper-resistant alfalfa varieties. These products are not genetically engineered, like Bt com, but have had leafhopper resistance bred into them using classical plant breeding techniques. Our research is focusing on the yield advantages of these products, the mechanism(s) of resistance and its effect on the pest and natural enemy community, and the potential changes in insect pest management that will accompany their use

Defining wireworm risk with GIS

Research at Iowa State University recently helped develop an early warning system for Iowa fields at risk from wireworms, by using geographic information system (GIS) technology. This information should help producers returning Conservation Reserve Program (CRP) land to corn production locate their high-risk fields. They can then follow recommended scouting procedures and avoid significant amounts of unnecessary insecticide applications in fields where wireworms are not detected

Potato leafhopper management in alfalfa

Potato leafhoppers have made their annual migration from the southern United States back to the alfalfa fields of Iowa. Small populations are being reported from across the state. During the last couple of years, producers have been planting potato-leafhopper-tolerant alfalfa to help prevent yield loss from this insect. Leafhopper-tolerant alfalfa looks, grows, and feeds similar to traditional leafhopper-susceptible alfalfa. It is different from susceptible alfalfa because the symptoms of feeding are much less severe

Early-season management of bean leaf beetle and bean pod mottle virus

During the past three summers, bean leaf beetles have reached historically high populations. At the same time, we learned that the insects are transmitting a disease called bean pod mottle virus. The occurrence of both of these pests in Iowa soybean has dramatically affected yields. Because the beetles are spreading the virus in soybean, we must rethink how we are going to manage these two pests