Experts explained why glyphosate-based herbicides did not produce results this year: issues and advice from Bayer company.

Journalists from the British agronomic publication Farmers Weekly interviewed a representative from Bayer to find out why glyphosate-based herbicides did not produce the desired results this year. During the spring period, farmers reported issues with weed control after glyphosate application.

Bayer agronomist Roger Bradbury conducted an analysis of the spring period to help farmers achieve better results in the future.

“We received several reports of unsatisfactory results. During our investigation, we found that unfavorable weather conditions, spraying regime, and low dosage led to ineffective weed control. Firstly, infrequent spray days and long intervals between them allowed weeds to proliferate significantly. Secondly, with limited spraying opportunities, farmers had to treat fields in adverse conditions or exceed the recommended speed. Thirdly, the wet conditions in early spring stressed the weeds, affecting their growth and glyphosate movement. Some treatments were delayed until stem elongation, when glyphosate moved only to the upper part of the plant and did not reach the root system, which could trigger regrowth,” he explained.

The expert emphasized that the correct spraying regime and speed are also important in the autumn.

“It is essential to ensure that the dosage is sufficient to destroy target weeds. For example, for couch grass, a minimum of 720 g/ha of glyphosate is required, and for black-grass, ryegrass, and cleavers, at least 1080 g/ha," advised Bradbury.

Rapid field treatment is not recommended. Spraying at speeds above 12 km/h leads to turbulence and herbicide drift. This results in uneven distribution of plant protection, with some areas receiving less than the required dose.

“In autumn, weeds are usually small, so improper treatment can miss some plants. Farmers need to closely monitor the results of glyphosate treatments to ensure effective control,” noted Bradbury.

The long-term effectiveness of the product depends on immediate weed control. Low doses of glyphosate increase the risk of resistance development.

“Correct dosage and application are necessary to achieve results. If you treat the field twice, make sure that cultivation is done between treatments as an alternative method of weed control,” advised the expert.

Bradbury also mentioned that Bayer is concerned about the reduction in dosage and the addition of citric or fulvic acid as compensation. Low efficacy control can lead to weed management issues.