Aphid predators have role to play in Spanish peppers in high summer

02/07/2020 - Controlling aphids in Spanish pepper crops in the height of the summer can become more challenging, although control can now be improved by diversifying the programme - introducing predators alongside the Aphidius-System.

“Spanish growers generally rely on the parasitoid Aphidius colemani to control aphids in a range of glasshouse crops,” explains Antonio Robledo, of Biobest Spain.

Temporary parasitism reduction

“During the hottest months of the year - July and August - soaring glasshouse temperatures make it more difficult for the adult parasitoids to emerge from the mummies.  This can temporarily lead to a reduction in the parasitism rate, impairing overall aphid control in the crop.

Diversify programme

“At this time of year, we advise growers to diversify their biological control programmes, introducing predators alongside the Aphidius-System. The options include the cecidomid mosquito Aphidoletes aphidimyza (Aphidoletes-System) or the syrphid fly Eupeodes corollae (Eupeodes-System) plus Sphaerophoria rueppellii (Sphaerophoria-System).

“These predatory larvae feed on the aphids, but conveniently don’t prey on the Aphidius colemani mummies - thus complementing the existing control programme.”    

Control glasshouse climate

In addition, to help optimise control levels Antonio advises growers where possible to control the greenhouse climate to avoid excess heat; for example, by improving crop ventilation and/or increasing crop humidity to favour the establishment of natural aphid enemies.