Atheta-System – one of the industry’s best-kept secrets

28/07/2020 - While some vegetable and ornamental growers swear by it, Biobest’s Atheta-System remains one of the industry’s best-kept secrets, according to IPM and pollination specialist Simon Foster.  “Used preventatively or curatively, it can play an important role keeping background populations of problem pests in check,” he says.

“The predatory rove beetle Atheta coriaria Kraatz is a voracious generalist predator of pests including fungus gnats (sciarid), shore fly, thrips pupae and various mites. It is proving particularly useful for controlling the underlying pest populations lurking in damp, dark places in the glasshouse; for example, under benches or in the corners where algae grow and water pools.  These overlooked areas provide places for sciarid and shore fly to breed or for thrips larvae to pupate.

“Growers use tools such as Hypoaspis-System and nematodes - applied directly to the crop and growing medium – to control these pests,” explains Simon. “However, all too often the source of the problem is elsewhere. Our Atheta-System is a fabulous partner for these products, as it manages the background population by tackling the problem at source.

“In many crops including Danish herbs, Dutch ornamentals and North American cannabis crops, Atheta-System is introduced under benches to target this hidden pest pressure. While well established in some localities and gaining popularity in others, it is not used as widely as it could and should be.”

Think like the pest

“In IPM systems it is essential to take a holistic view of the crop and facility and target the pest, not only in terms of its life-stages, but also its different spatial ecological environs,” Simon continues. “It can be helpful to ‘Be the bug’ - and think like the pest!  Where would you live and how would you exploit the resources available in the crop? Only then can you begin to address the entire spectrum of crop protection needs, without leaving loopholes for pests to exploit.”

The lifecycle

Depending on the temperature, the Atheta life cycle generally takes around 3 weeks.  The slender larvae, which are pale white/yellow in colour and about 4mm in length, prefer to stay hidden in the growing medium.  The shiny black adults – just 3-4mm long – emerge from the pupae about two weeks later.  Able to fly, the adults are much more conspicuous in the crop and generally live for 3 to 4 weeks plus. Each female is capable of laying around 100 eggs and each adult rove beetle can consume 10-20 prey per day.

Use year-round

“In glasshouse conditions, Atheta are non-diapausing (non-hibernating) and can be effectively used year-round,” explains Simon. “One application applied early in the season is often sufficient to give season term establishment.  To optimise efficacy, we recommend the beetles are applied in piles - each containing at least 10 adults – and, crucially, have access to moisture.”

The Biobest Atheta-System product contains a nominal 500 mobile beetles – with additional bonus eggs and larvae. “We aim to ensure growers introduce 500 healthy, mobile beetles upon receipt,” explains Simon. “If applied carefully in damp, humid areas, the additional ‘over-pack’ of pupae and eggs will successfully develop into additional larvae and adults - giving growers a bigger bang-for-their-buck!”

Preventative or curative

For preventative control, Biobest recommend applying Atheta-System at a rate of 1-2 per m² early in the crop cycle, particularly focussing under benches and in damp areas. A single application is often enough to establish a predator population for the entire season, although it will fluctuate depending on the conditions and pest pressure.

In specific problems areas, Biobest recommend introduction Atheta-System at a higher curative rate - of 10-15 beetles per m².