Potato Review

www.potatoreview.com POTATO REVIEW SEPTEMBER/OCTOBER 2020 33 NATURAL CONTROL METHODS As yet little is known about the e ect of wildflower strips on the interactions between aphid populations and their natural enemies. period. is is because natural enemies take time to build their numbers. “ e problem with natural enemies is they are at their maximum e ect after the aphids are there in su cient numbers to have been transmitting virus.” ere can be other complexities to the system too; as there can be antagonistic coevolution by reciprocal adaptation of the hosts (the pests). “ ere has been a lack of a holistic IPM approach that integrates both traditional and modern tools which we are hoping to help ll,” said Eric. “We aim to have a better knowledge of the roles biology, ecology and evolution play, which we believe can provide new inspirations for aphid and potyvirus control.” Pyrethroid resistance ere is known resistance to pyrethroids in peach potato aphids, willow carrot aphids and bird cheery oat aphids. Recent work on grain aphids has demonstrated a knock- down resistance (kdr) mutation confers a 35 fold resistance shift to pyrethroids (Source: Dr Steven Foster, Rothamsted Research 2013). In addition, there is recent evidence of pyrethroid tolerance in Bird cherry-oat aphid in Ireland. Increasing pyrethroid spraying may increase selection pressure on speci c aphid species and has a negative e ect on any bene cials in the crop. enemies around rather than building up their populations therefore having some more permanent habitats around the eld edges will help build up natural enemies.” Previous pest monitoring has indicated e ects along transects extending out form the strips up to 50m, so this is likely to be the maximum distance any natural enemy would have to travel, he adds. However, as yet little is known about the e ect of wild ower strips on the interactions between aphid populations and their natural enemies nor how e ective they are at increasing distance into the crop. He also reminds growers that although biological control using natural enemies of aphids for predation, parasitism and pathogens can be e ective, there is a lag “There has been a lack of a holistic IPM approach that integrates both traditional and modern tools which we are hoping to help fill.”