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

Comparison of a Conventional Crop Rotation with an Organic Forage-Based Crop Rotation
7/6/2020

Due to continued increases in demand for certified organic grains, crop farmers that have transitioned from conventional to certified organic grains report higher net returns per acre (McBride et al., 2015; Greene et al., 2017; Greene and Vilorio, 2018; Center for Farm Financial Management, 2020).  Despite this, certified organic land accounts for less than 2 […]

USDA Announces Flexibilities for Producers Filing ‘Notice of Loss’ for Failed, Prevented Planted Acres
7/3/2020

The U.S. Department of Agriculture (USDA) is providing additional flexibilities for producers to file on acres with failed crops or crops that were prevented from planting because of extreme weather events. USDA’s Farm Service Agency (FSA) is adding these flexibilities for Notice of Loss on both insured and uninsured crops to enable Service Centers to best assist […]

China Imports Still Not on Pace to Meet Phase One Targets
7/2/2020

Earlier this week, Bloomberg News reported that, “China’s purchases of U.S. goods increased last month as the economy continued its recovery from the coronavirus shutdowns, but imports are still far behind the pace needed to meet the terms of the ‘phase one’ trade deal. “By the end of May this year, China had only bought about 19% of the […]

Your browser is out-of-date!

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