Peppers spider mite free with Phytoseiulus-System

8 August 2022
As happens every year, spider mite has appeared early in sweet pepper crops. While the infection pressure and pest distributionwill differ per greenhouse, the one certainty is thatPhytoseiulus persimilis can deal with sudden population increases. Thispredatory mite canrid a crop of spider mite hot spotswithina few days.

Red spider mite - the bean spider mite,Tetranychus urticae - is one of the most common pests. Keeping it under controlis an annual challenge, says Biobest crop advisor Bart Elseviers. "However, by scouting carefully and introducing predatory mites in time, growers can keep spider mite well controlled,” he says. 

Preventative introduction
Bart recommends starting the control programme at the beginning of the crop, with introductions ofAmblyseius degenerans(Degenerans-System) and sachets ofAmblyseius cucumeris (ABS-System). 

"Our ABS-System ensures a continuous release of predatory mites over several weeks,” he says. “This ensures growers achieve a healthy population ready to take immediate action when the first spider mite appears, the so-called 'standing army'."

Degenerans-System
Biobest is the only company producingAmblyseiusdegenerans - which according to Bartworks particularly well in combination with Amblyseiuscucumeris. 

"Other combinations also work well, such as Swirskii-System and Montdorensis-System- the choice often depends on whichpests are present,” he explains. “For example, ifyou have whitefly issues,Swirskii-System is the better option. “Biological pest control programmes should be customised to the situation in individual crops. Anyone needing advice, including regarding the best dose rate, should contact their Biobest advisor.”

Curative addition
While the preventative predatory mites play a useful role slowing down red spider mite infestations, Bart warns the pest pressure can still increase laterin the crop. 
“Phytoseiulus-System then plays its key role,” he says. "This highly specific and mobile predatory mite has an enormous appetiteenabling its population to increase faster than the spider mite. Phytoseiulus-System should be applied curatively at a rate of 20 to 25 units per m² - depending on pest pressure.”“Thisbeneficial mite should be sprinkled near the spider mite hotspotswhere it will immediatelyget to work. If necessary, the treatment can be repeated several times."

Keep scouting!
“Phytoseiulus-System develops best at low humidity and high temperatures,above 30°C - so warm and dry conditions,” continues Bart. "If greenhouse conditionshave been cool and humid for a while, this pest can get the upper hand again. It istherefore wise to scout well after such a period and possibly reintroduce Phytoseiulus-System."

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