Oct 28, 2020

Andersoni-system well suited to Spanish raspberries

Raspberry growers in southwest Spain tend to have two crops, at different stages, in production at the same time. One is grown from established bushes previously pruned back, while the second crop is planted more recently.

By adopting this cropping practice, Spanish raspberry growers are successfully extending their harvest calendar, supplying fruit from October through to July.

Spider mite a key challenge

 One of the major pest challenges facing Spanish raspberry growers is spider mite.

“Control strategies tend to start with preventative releases of Andersoni-System in combination with Phytoseiulus-System and Swirskii-System,” Biobest Group’s technical advisor Miguel Claros said in a news release. “Our control strategy also recommends introducing Andersoni-System later in the season to augment control; at this stage in combination with our Feltiella-System and Phytoseiulus-System.

Preventative approach

“As well as feeding on a range of mites, andersoni mites are pollen eaters. This means they can effectively be deployed preventatively – helping them establish a good population in the crop before the pest pressure has a chance to build up.”

A highly effective predatory mite, andersoni nymphs prefer to feed on the eggs and young stages of two-spotted spider mite, as well as the European red spider mite, Lewis mite and other mite pests. Meanwhile the adult predators readily eat – and control – all the pest mites’ lifecycle stages.

Highly mobile

“Andersoni also benefits from being highly mobile,” said technical advisor María Parra. “It can spread fast and easily throughout the raspberry crops – particularly where plants are touching.

“Under normal conditions, the predator also has a shorter lifecycle. Taking just 7-8 days at 21° C (45-46° F) to complete a generation, it has the ability to build up a population more quickly than the pest mites.

Withstands temperature fluctuations

“At low temperatures andersoni mites enters diapause (hibernation), re-emerging when conditions improve sufficiently. This means it can remain in the crop, lying in wait, from one crop cycle to the next. Last but not least, our Andersoni-System can usefully withstand large temperature changes – from as low as 6° C to as high as 35° C.

“Well adapted to the crop and the growing conditions in this region of Spain, our Andersoni-System has proved its worth and is playing an increasing role in the prevention and control of a range of mite pests in raspberries.”

– Lise Verachtert, Biobest Group