Brassica growers are being urged to keep pest pressure under close review as warmer, more changeable conditions continue to make pest movement harder to predict.

With crops grown to meet strict quality, uniformity and harvest schedules, even moderate pest pressure can have a significant impact on marketability, particularly where plants are already under stress from weather, transplanting delays or tight spray windows.

Antonia Walker, commercial technical manager at FMC, says growers and agronomists need to stay alert to the risk posed by key brassica pests throughout the growing period.

“Brassica crops face pressure from a complex mix of pests, including cabbage root fly, diamondback moth, caterpillars and aphids,” she explains.

“Damage can affect crop vigour, reduce leaf area, increase the risk of virus transmission and lead to uneven growth. For crops destined for fresh produce markets, that can quickly become a quality and marketability issue.”

Miss Walker says changing weather patterns are making pest pressure more difficult to manage, with milder winters allowing more pests to survive and warmer spells encouraging earlier or more rapid movement into crops.

“In practice, pest pressure is becoming less predictable. It can vary significantly between regions, fields and seasons, so relying on calendar-based decision-making is becoming increasingly risky,” she says.

This makes monitoring central to any effective integrated pest management programme. Regular crop walking, pheromone traps and aphid forecasting can help growers understand when populations are beginning to build and where intervention may be needed.

However, she adds that product choice and timing remain critical, particularly as growers have fewer active ingredients available and must steward chemicals carefully.

“One of the key decisions in brassica pest control is when and where to use diamide chemistry, as only one diamide application can be used in the crop,” she explains.

“That decision needs to be made as part of the wider programme, taking into account crop risk, pest history, planting date and likely pressure later in the season.”

Verimark® is FMC’s root-zone diamide option, containing cyantraniliprole, applied as a module drench before transplanting.

“The active ingredient is taken up through the roots and moves systemically through the plant, helping to protect crops as they establish and supporting the wider pest control programme,” she says.

“Verimark® offers strong cabbage root fly control, while also providing useful activity on caterpillar pests and some incidental aphid suppression,” says Miss Walker.

“Using it upfront can help reduce pest pressure during a vulnerable stage of crop development, giving plants a stronger foundation for the rest of the season.”

She concludes: “With pest pressure becoming harder to predict and fewer options available, brassica growers need to plan carefully, monitor closely and make every application count.

“Protecting crop uniformity and quality is not just an early-season priority. It is something that must be actively managed throughout the crop’s development.”