Sugar beet (Beta vulgaris) is an economically important crop, contributing ~£800m to GDP each year and supporting 13,000 jobs. Like all crops, sugar beet is susceptible to pests and diseases. One newly emerging economically important pest is the Mangold fly, or beet leaf miner (Pegomya hyoscyami), complex. Larvae of these leaf mining flies mine into sugar beet leaves, resulting in a reduced photosynthetic area, increase sensitivity to herbicides, increased likelihood of frost damage and ultimately reduced yield. In the past few years the British Beet Research Organisation (BBRO; CASE partner for this project) have been receiving increasing numbers of reports from British farmers with infestations throughout sugar beet growing regions in East Anglia and North-East England. Notably, while the most vulnerable stage of the crop is currently protected by neonicotinoid seed treatments, later infestations are causing significant damage once seed treatments have worn off. It is these later infestations that are becoming increasingly common, and are causing serious concern among the farming community. This scenario is compounded by the fact that further restrictions on the use of neonicotinoid seed treatments are predicted and foliar insecticides are of limited use in controlling this leaf miner once it is within the leaf. Together, recent events highlight an urgent need for novel control strategies and a greater understanding of P. hyoscyami.
There are currently serious gaps in our knowledge of the basic biology and ecology of P. hyoscyami populations within the UK, which preclude development of management strategies. A possible complex of four species has been described based on morphological data
(Michelsen 1980, Ent. Scand.), but it is unknown which species are affecting UK sugar beet crops, nor whether these species differ in the extent of crop damage caused. Knowledge of the distribution P. hyoscyami in the UK is currently restricted to anecdotal evidence from farmers, and evidence regarding population size, population origin and connectivity within and among species is absent.
Outcomes / Key Message For Growers And Industry
Two distinct species of leaf miner found, one with a preference to sugar beet.