With summer soon upon us, thrips pressure is set to increase - warns Koen Merkus, IPM & Pollination Specialist at Biobest. “Fortunately, our predatory mites can deal with this pest effectively provided the population is large enough,” he says. “To achieve this, we recommend using Nutrimite™ to give the predator population an initial boost - creating a strong line of defence ready for when the pest appears."
An 100% natural feed supplement based on selected pollen, Nutrimite™ is particularly appetising to Swirskii-System (A. swirskii) and Montdorensis-System (A. montdorensis). Sweet pepper growers using Degenerans-System (A. degenerans) are also experiencing good results using it.
"Nutrimite™ helps the predatory mites prosper in periods when food (prey) is in short supply,” explains Koen. “We recommend using it after the initial introduction of predators, as well as to provide support to an established population - if thrips are scarce. This supplementary feed will help quickly and effectively bring, and maintain, the predatory mite army to its fighting strength. In this way, you stay one step ahead of pests.”
Of course, the predator population can also be strengthened by constantly introducing new predatory mites. Koen has noticed ornamental growers generally opt for the supplementary feeding method.
"By introducing predatory mites less frequently, less carrier is deposited in the crop,” he explains. “Although not harmful in itself, the carrier granules can reduce the aesthetic value of a plant. In contrast, Nutrimite™ cannot be seen and indirectly leads to equally high numbers of predatory mites. Employing our supplement, swirskii, montdorensis and/or degenerans can reproduce more rapidly in a natural way."
Nutritious for two weeks
Nutrimite™ remains nutritious for up to two weeks. Unlike, for example, factitious prey, it does not dry out, which means that users can benefit from it for a longer period. Koen recommends blowing a dose of 500 grams per ha, every two weeks - from the first introduction of predatory mites.
"In crops watered from above, the pollen is likely to be washed off the plants sooner,” he warns. “To compensate, in these situations we advise applying 250 grams per ha weekly."
As the pollen is relatively unattractive to honeybees, bumblebees and Western Flower Thrips (WFT), only the predators will benefit - helping optimise control.
Keep on monitoring
As always, scouting is important for monitoring the success of the biological control strategy. This can be achieved by simply counting WFT numbers on sticky traps and/or via crop observations - as well as other thrips species that might appear in the crop.