This spring Atlantis has faced its toughest challenge yet but it has performed commendably, says manufacturer Bayer CropScience.
Grass weeds continue to plague cereal crops and herbicide application timing remains critical for successful control. But this spring's weed control has been particularly challenging due to a combination of unfavourable factors.
"It has been interesting to monitor the performance of Atlantis over different stages of the growing season," says Bayer's Gordon Anderson-Taylor. "Typically, applications made before Christmas consistently resulted in black-grass control levels of 100% or just below.
"Following what have proved to be the most difficult spring conditions since Atlantis was launched, spring applications have sometimes resulted in a lower level of control than previously experienced with the product," he continues.
"This comes as no great surprise considering the limited number of suitable opportunities to spray, but an average of 90% black-grass control constitutes a good performance given the circumstances - a performance which still must be seen as far above what any other product could offer at these timings."
Bayer CropScience trials have again highlighted the importance of earlier timings for black-grass control. "This year has been a good illustration of the increased risk incurred by delaying black-grass control until early spring, when the weed growth stages are more advanced, temperatures can be lower and the number of spray days can be limited," he explains. "Furthermore, early removal of weed competition ensures yield returns are optimised."
"The extended cold period in March deterred some growers from spraying. By the time the weather had warmed up, and weeds were actively growing again, we were well into April. Atlantis was tackling some weeds at a very late growth stage, with some black-grass plants at ear emergence."
While Atlantis coped well with the largest weeds it has faced to date, the combination of application delay and sub-optimal conditions has, in some cases, raised concerns about the level of control achieved and the increased risk of resistance.
"Future planning for black-grass and rye-grass control must take all issues into account," Dr Anderson-Taylor emphasises. "Autumn applications may make growers feel they've compromised control by potentially missing a few later-germinating weeds, particularly in the case of rye-grass which continues germination through autumn and spring.
"But autumn sprays lead to a higher total level of control, increased yields and help to reduce the risk of resistance."
