Teagasc is offering a herbicide resistance testing service for tillage farmers.

Uncontrolled weeds on cropland are normally a result of choosing the wrong herbicide, applying it at an insufficient rate or encountering issues during application, Teagasc has said.

However, if a farmer cannot otherwise explain the presence of these weeds, it can indicate a herbicide resistance issue in the field.

Resistance testing provides the farmer with essential information on how to put a control plan in place.

Crops specialist at Teagasc Ciaran Collins says with the break in harvest, this is “the last opportunity to inspect crops for uncontrolled weeds” and to collect samples for testing if resistance is suspected.

Grassweed types

All grassweeds should be treated with caution, particularly blackgrass, brome species and Italian ryegrass, and a test is advised where these weeds are present.

Herbicide resistance is not confined to grass weeds - chickweed is increasing in abundance each year in addition to poppy, corn marigold and speedwells.

Teagasc is also urging any landowners with uncontrolled meadow grass in their winter crops to avail of a test.

“The level of annual meadow grass in winter crops seems to be higher than normal this year. Whether this is a symptom of the wet weather in 2023/2024 or an indication of a greater issue is difficult to determine at this stage.”