Menu

Grasshopper Activity Observed

Grasshopper activity has been noted this week in Iowa. These insects feed on grasses and weeds, and can become field crops pests. In corn and soybean, feeding is frequently, but not always, restricted to field edges. When crop injury does occur, it usually is related to drought conditions due to a reduction in natural vegetation.

Description
Many short-horned grasshoppers exist and range from 1-2 inches in length as adults. The wings are usually developed but some short or absent wing forms are possible. Nymphs and adults move by jumping with enlarged hindleg femurs and some adults fly short distances. Two common species, the differential grasshopper and the redlegged grasshopper, are most likely to cause field crop injury in Iowa.

Young grasshopper nymphs eat irregular-shaped holes in tender leaf tissue and may consume the entire seedling. Older nymphs and adults can consume all of the leaf except the tougher veins. Grasshoppers chew through green soybean pods (which bean leaf beetles will not do) and destroy the seeds within. They can also feed on vegetative corn, starting with the outer leaf edge and moving inward. They can interfere with pollination by feeding on silks, and they will chew on developing kernels.

Adult and immature grasshoppers will consume most leaf tissue expect the tough veins, and can feed though pods later in the season.

Management
Grasshoppers are difficult to control because they are highly mobile and insecticides are more effective on nymphs. Reducing grasses and other weeds within and around fields will discourage adults from feeding and mating in that area. Scout field borders first before moving to interior. The economic thresholds are based on leaf area consumed or percent defoliation. In soybean, a foliar treatment may be justified if defoliation exceeds 40 percent before R1 (full bloom) or 20 percent after R1. Consider an insecticide application in corn if grasshoppers are clipping silks, feeding on ear tips, or are removing foliage above the ear leaf. Border treatments are recommended if infestations are restricted to field edges.

Biology. Female grasshoppers lay egg masses into bare, moist soil in the late summer or fall. Nymphs emerge throughout the spring, but the timing is based on temperature and species. Nymphs molt several times and require temperatures over 68° F to be active. Nymphs mature over 40-60 days and most grasshoppers are adults by August.

Source: Iowa State University 

Recent News

Fall-applied Herbicides-What Goes Around Comes Around
9/22/2020

Fall herbicide treatments have fallen off over the past several years for a couple of reasons, among them the effectiveness of new soybean trait systems for managing marestail, some generally crappy weather in late fall, and efforts to reduce input costs.  We are seeing a resurgence in some weeds, such as dandelion, which respond well […]

New Round of Farm Aid for COVID Losses Announced, and Causes Snag in Congressional Spending Bill
9/22/2020

Andrew Restuccia and Jesse Newman reported in Friday’s Wall Street Journal that, “President Trump unveiled $13 billion in new aid to farmers facing economic harm from the coronavirus pandemic as he aimed to boost support among rural voters at a campaign rally. ‘I’m proud to announce that I’m doing even more to support Wisconsin farmers,’ said Mr. Trump, speaking outside […]

Corn Silage Needs Adequate Moisture to Ferment
9/18/2020

Early season frost is challenging for corn silage producers, according to Karl Hoppe, Extension livestock systems specialist at NDSU’s Carrington Research Extension Center. Frost makes an abrupt end to the corn-growing season. This begins the dry-down period for the corn plants. “Good corn silage fermentation requires adequate moisture to reduce dry-matter loss and spoilage,” Hoppe […]

Your browser is out-of-date!

Update your browser to view this website correctly. Update my browser now