Each day this week we are releasing information delivered at the Soybean Field Day at the NCDA&CS Piedmont Research Station in September for those who could not attend.
Environment, genetics, and management interact to affect soybean seed quality. Changes in soybean management across North Carolina have resulted in more encountered seed quality issues and a robust need to understand drivers in seed quality declines. Hot and humid weather conditions early in the year can allow for growth and spread of fungus and disease that can cause seed damage. Insect pests may also interact with seed quality issues. We need a more robust understanding of what causes seed quality declines and management strategies to protect seed quality are needed.
From 2021-2023 research is being conducted on the influence of planting date, maturity group, and pest management on soybean yield and seed quality across the state. The study is being conducted in a split-split plot design with main plot as planting date (late March, mid-April, mid-May), sub-plot as maturity group (III, IV, V), and sub-sub-plot as pesticide management which includes combinations of fungicides and insecticides.
Pest management affected soybean yield consistently across environments, planting dates, and maturity groups, with multiple fungicide applications increasing yield compared to the untreated control. The only treatment that protected seed quality was later-season insecticide applications coupled with fungicide applications.
– Kelly O’Reilly, graduate student and Dr. Rachel Vann, Soybean Extension Specialist.
Most of our soybean insect pest thresholds are based on scouting with a sweep-net. One swoosh of the net equals one “sweep.” There are a few important soybean insect pests that we have in North Carolina and the only way to know if control is warranted is to determine if the pest population is above the threshold.
It is important to spray only when necessary because there are several beneficial insects that may already be keeping pest populations low. Numbers of the beneficial insect species in the field do not recover as quickly as pest populations do after a broad-spectrum insecticide has been applied. This helpful guide has color photos of insects and can help farmers monitor pest populations as well as some high-quality photos of beneficial insects we may find.