Simon's Seasonal Insights: Onions
Early success faces moisture challenges
With onion drilling completed in good time before the end of March and generally good soil conditions, this year's crop has plenty of potential to deliver higher yields and finish on schedule. Unfortunately, dry weather throughout April caused soils to dry out and forced growers to irrigate where available.
This has slightly taken the shine off the promising start, as some crops now vary in growth stage and population, bringing the usual problems of difficult weed control.
However, it's still all to play for, and having a large proportion of crops at 5 true leaves by mid-June this year is a significant positive.
Pest and disease – all quiet so far
The major early pest issue is Bean seed fly. Although activity is currently low, it remains one to watch. Emergence typically rises through mid-May.
Regarding disease, while downy mildew (above) hasn't yet been reported, the control strategy should begin at the 5-true-leaf stage regardless. Irrigation can also increase disease risk.
When planning disease control, a golden rule is to ensure crops are sprayed weekly, and resist stretching intervals even in dry weather. This will ensure newly emerging leaves are protected.
Product choice with initial applications tends not to be as important, but once the canopy starts to thicken and bulb formation is under way, the most effective products should be targeted here. Alternating ORONDIS® Plus + AMISTAR® with products like Unicur will give the strongest protection against disease at this critical stage
QUANTIS® helps crop resilience and maintain returns
Drilled crops such as onions, which are grown on light soils, are vulnerable during prolonged dry periods, making it almost impossible to maintain adequate soil moisture levels. This results in periods where the crop becomes drier than desired and inevitably stops growing, and even worse, experiences cell damage
QUANTISTM supports growth by acting as an osmoprotectant, keeping stomata open, sustaining photosynthesis, providing carbohydrates, and reducing oxidative damage.
Trials with QUANTISTM applied at 2 l/ha every 14 days from the five true leaf stage increased bulb size and yield, as shown below.
