ISU: ‘Halo Effect’ From ILeVO Soybean Seed Treatment Doesn’t Result In Yield Loss

Farmers who were lucky enough to plant soybeans and spray pre-emergence herbicides in between rain events may now be seeing discolored or injured seedlings, reports a group of Iowa State University-Extension researchers in a recent Integrated Crop Management News.

Reports of fields with these issues are widespread across Indiana, Iowa, and surrounding areas, and many farmers and crop advisors are questioning if damage is more severe when pre-emergence herbicides are applied to fields that have been planted with seed treated with the new fluopyram fungicide seed treatment ILeVO.

Advertisement

Fluopyram fungicide

Top Articles
TFI: Phosphate and Potash Are Critical Minerals, Senate Bill to Solidify

The fungicide fluopyram (ILeVO; Bayer CropScience) is currently marketed as a seed treatment to manage sudden death syndrome (SDS). This seed treatment can result in a discoloration on soybean cotyledons that can resemble disease or other abiotic stress such as herbicide injury. The discoloration occurs because the fungicide is moderately systemic within the soybean plant, so it will naturally move to the plants “sinks”, the roots and cotyledons. This accumulation can result in phytotoxicity, causing the tips of the cotyledons to turn a yellow-brown color. This necrosis is typically uniform and present on every seedling grown from an ILeVO treated seed; however, environmental conditions may impact the frequency, uniformity and severity of the phytotoxicity observed. The phytotoxicity is not usually found on the unifoliate or trifoliate leaves. Research conducted by several Land Grant Universities and Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) demonstrated that this phytotoxicity, also referred to as a “halo effect”, does not result in long-term soybean stunting or yield loss.

View the full report on the Iowa State University Extension Website.

0
Advertisement