Simon's Seasonal Insights, Brassica, July 2024
Looking for positives!
Looking for positives in what has been a difficult season so far, showery weather has helped to keep insects at bay. Aphids have been present at lower numbers than predicted at the start of the year and caterpillars have also been difficult to find to date.
Brassica pests appearing
One pest to watch towards the end of June is the appearance of second-generation cabbage root fly. It depends on the season, but over the last few years we have seen an increase in damage in broccoli florets, due to egg laying on the head close to maturity. Warwick Crop Centre are again providing a forecast for activity on their website this year.
For crops at risk, an insecticide will help reduce the presence of larvae, MINECTO® One has a label recommendation for this pest. Application of HALLMARK® Zeon for caterpillars could also be helpful.
Brassica Disease
It’s early for disease to build, but ringspot is easy to find in broccoli. Although few crops justify a fungicide presently, early cabbage - particularly savoy - would benefit from a protectant spray, as the early varieties can be more susceptible.
AMISTAR® TOP is a good option, as it will give broad spectrum disease control of leaf spots.
Biologicals
Despite the unsettled summer weather so far, July usually records the highest temperatures, low rainfall and dry soils.
Planting is a particularly challenging period for crops, as they move from a pattern of even watering and steady transpiration in the calm conditions of the glasshouse, to the vagaries of the open field.
Application of QUANTISTM around planting
Although to date our data is limited, in 2023 we saw a visual effect from applying QUANTISTM to brassica modules at planting. Production of leaves was quicker in treated modules, and visually there was less of a planting check.
In a separate treatment, where Brussels sprouts were sprayed with QUANTISTM four weeks post planting, data from an un-replicated trial conducted by the Allium and Brassica Centre showed there was a yield uplift in treated plants. Further trials are in progress this year to build our understanding."
About Simon: Simon Jackson is Field Technical Manager at Syngenta, specialising in pest and disease control for vegetable crops.
