Potato Review

32 POTATO REVIEW SEPTEMBER/OCTOBER 2020 NATURAL CONTROL METHODS pest control potential of the margins by the use of ‘banker plants’ where natural enemies of the aphids can be reared. ree individual species (corn ower, common vetch and yarrow) have all been identi ed as having the potential to serve as banker plants based on the density and/or diversity of alternative aphid hosts they are likely to support, said Eric. “Obviously the plants need to have a relatively low growing habit if they are to be sown in the tramlines.” Going on to speak about previously tested ower strips, he emphasised that in Switzerland, research conducted by Matthias Tschumi has found ower strips to be highly e ective in attracting natural enemies of aphids and in decreasing aphid densities. Increased numbers of adult natural enemies inside ower strips compared with potato controls; hover ies were up 339%, ladybirds by 177% and lacewings by 233%. Eric said: “ ese results con rm the attractiveness of the o ered resources, with particular bene t for hover ies in adjacent potato crops. Moreover, ower strips strongly promoted hover y diversity, and tailored ower strips enhance biological control of aphids in nearby potato crops and provide complementary bene ts for natural enemy biodiversity. “As these are rotational treatments, the bene t is by moving existing natural AHDB trials investigating predator biodiversity At the AHDB Strategic Potato Farm at Morphie, near St Cyrus, alternative practices that can be introduced into pest management programmes to sustainably manage viruses by increasing natural predator biodiversity are being investigated through the use of cereal purge and wild ower strips. Eric said: “ is is an approach that focuses on prevention or suppression of pests through a combination of methods such as biological control, habitat manipulation, modi cation of cultural practices and targeted chemistry. “ e platform should encourage the con dence for growers to adopt Integrated Pest Management more widely, to improve potyvirus control whilst reducing insecticide use in arable crop systems.” “As these are rotational treatments, the benefit is by moving existing natural enemies around rather than building up their populations.” Flower strips strongly promoted hoverfly diversity.