Pollen-feeding Degenerans-System demonstrates robustness

23/02/2021 - It is the ideal time to introduce the robust, generalist predator Amblyseius degenerans to pepper crops – says Tim Crittenden, technical sales manager for Biobest UK. “A single carefully planned introduction of our Degenerans-System is all that is needed to build up a healthy ‘standing army’ of these predatory mites. While complementing the IPM programme, we’ve observed Degenerans-System also playing a key role later in the year - when spray programmes targeting Nezara viridula (stink bug) have impacted negatively on predatory mites.”


Degenerans is widely deployed in UK-grown capsicum crops of bell, sweet and chili peppers. Complementing Orius-System and Amblyseius-System, it is primarily introduced to capsicum crops to help control thrips larvae and spider mites – particularly the two-spotted spider mite (Tetranychus urticae).


“A pollen-feeding mite, Degenerans-System should be introduced as soon as the first true flowers appear in the crop – normally 3-5 weeks after planting,” explains Tim. “The introductory rate depends on factors including pest pressure.

“This predator is capable of explosive population growth. From a single introduction, a large ‘standing army’ of Degenerans-System quickly builds up in the crop – ready for when the first thrips and spider mites appear.”

Mitigating negative pesticide impact

“Later in the season, generally around July – August time, we see stink bug pressure builds up in UK pepper crops,” says Tim. “With no biological solutions currently available for this damaging pest, growers tend to resort to chemical spray programmes which knock back the pests, as well as beneficial predators. By mid-summer the thrips pressure has usually peaked, however, it is still important to keep the population under control.

“Research has shown that pollen-feeding predatory mites, such as Amblyseius degenerans, are able to mitigate the negative effects of pesticides faster than those that simply predate on pests,” says Tim. “We have observed this happening in UK pepper crops. Even when all, or most, pests have been knocked back, Degenerans-System - with its explosive population growth on pepper pollen - appears to recover quickly.

What to look for

“Another advantage of Amblyseius degenerans is that it is easily visible in the crop using the naked eye,” says Tim. “A relatively large, dark brown to black mite, it congregates in capsicum flowers - where thrips are found. Quick to reproduce, at 25°C the translucent, ellipsoidal eggs hatch into adults within a week.”

How to introduce

Degenerans-System is supplied as 500 adult mites in a 100ml bottle. Introductions are made using Bio-Boxes at distribution points in the crop. Depending on the thrips pressure at the time of introduction, population establishment can be further accelerated and enhanced using Nutrimite™ – Biobest’s highly nutritional feed supplement.

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