This week soybean aphids were found in several northeast Nebraska fields at low numbers. Although it has been too hot for soybean aphids to thrive, populations could quickly increase with cooler temperatures. Scouting is recommended at this time.
The current recommended economic threshold for late vegetative through R5 stage soybeans is 250 aphids per plant with 80% of the plants infested and populations increasing. Depending on economic conditions, this generally gives you about five to seven days to schedule treatment before populations reach economically damaging levels.
July is when growers start to see a variety of defoliators in Nebraska soybean fields. It's easy to overestimate the amount of defoliation and soybean plants can compensate for some leaf area loss. This article describes how to assess defoliation and provides basic treatment thresholds.
While soybean defoliation, the most common injury to soybeans from insects, can look devastating, soybean plants can often compensate for the leaf loss. When making pest-management decisions, crucial considerations are the size of the remaining leaf canopy and the soybeans' growth stage.
The first western bean cutworm moths were captured in University of Nebraska-Lincoln black light traps June 23 at Clay Center, June 27 at North Platte, and June 30 at Scottsbluff. Flights are currently increasing, particularly in North Platte. Scouting should be underway across much of the state.
Populations of immature grasshoppers are being reported in areas bordering crop fields in several parts of eastern Nebraska. If these grasshopper species are one of the four major species that are likely to infest cropland, control may be warranted. Check here are scouting guide and treatment thresholds and recommendations.
Guide to identifying and managing alfalfa and clover leaf weevils in alfalfa. While research in northeast Nebraska has shown that clover leaf weevil larva feeding does not cause yield reduction to first cutting alfalfa, alfalfa weevil feeding can cause severe losses to yield and quality of the first cutting. This is why it's important to correctly identify the type of weevil feeding causing damage.