Time for preventative predatory mite introductions in raspberries
As raspberry plants come out of dormancy, pests generally appear soon. For crops grown in tunnels, now is the time to be prepared – says Biobest advisor, Gaby van Kemenade. To stay one step ahead, she recommends growers make preventative introductions of Californicus-Breeding-System or Andersoni-Breeding-System.
As the product names suggest, Biobest offers californicus or andersoni predatory mites in breeding sachets. These contain food enabling the predatory mites to reproduce and be released on to the crop over a six-week period.
“The strategy depends on the situation in the crop,” explains Gaby. “While A. californicus mites are more specialised in controlling spider mite, A. andersoni mites have a more generalist approach - also targeting thrips and other pest mites. Andersoni is also very much at home in woody crops and is more resistant to cooler temperatures.”
"The sachets have an integral hook and are easy to hang in the crop. We recommend hanging one sachet every 2 metres as standard. These predatory mites are also available as sprinkling material - Californicus-System and Andersoni-System.”
Phytoseiulus-System as temperatures rise
“Later in the season, as temperatures start to rise, spider mite hotspots can develop necessitating the use of more beneficials,” says Gaby. “We recommend extending control with Phytoseiulus-System. Effective at 15ªC and above, these voracious Phytoseiulus persimilis, predatory mites tackle spider mite hot spots.
“We recommend an introduction rate of 15 to 20 mites per metre. Phytoseiulus has a striking red colour and is a real spider mite specialist - it cannot survive without the pest.”
Gaby has another tip for raspberry growers – this time relating to optimising pollination rates.
"In April, raspberries in tunnels come into flower but the days can still be cold and dark causing pollination issues,” she says. “To optimise yields, we recommend deploying bumblebees. Compared to other pollinators, they continue to fly and pollinate better under these conditions.
“Our Multi-Hives contain three bumblebee colonies, packed in a weatherproof outer box. This 'jacket' is also available for individual nests under the name Bee-Coat. This protection ensures bumblebees continue to carry out their work in the best possible way."
For more information, contact Lise Verachtert (firstname.lastname@example.org).