The potential of decision support systems to improve risk assessment for pollen beetle management in winter oilseed rape

Abstract

BACKGROUNDThe reliance on and extensive use of pyrethroid insecticides have led to pyrethroid resistance in pollen beetle (Meligethes aeneus). Widespread adoption of best practice in pollen beetle management is therefore needed. Decision support systems (DSSs) that identify the risk period(s) for pest migration can help to target monitoring and control efforts, but they must be accurate and labour efficient to gain the support of growers. Weather data and the phenology of pollen beetles in 44 winter oilseed rape crops across England over 4 years were used to compare the performance of two risk management tools: the DSS proPlant expert, which predicts migration risk according to a phenological model and local weather data, and ‘rule‐based advice’, which depends on crop growth stage and a temperature threshold.RESULTSBoth risk management tools were effective in prompting monitoring that would detect breaches of various control thresholds. However, the DSS more accurately predicted migration start and advised significantly fewer days of migration risk, consultation days and monitoring than did rule‐based advice.CONCLUSIONThe proPlant expert DSS reliably models pollen beetle phenology. Use of such a DSS can focus monitoring effort to when it is most needed, facilitate the practical use of thresholds and help to prevent unnecessary insecticide applications and the development of insecticide resistance. © 2015 Rothamsted Research Ltd. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The potential of crop management practices to reduce pollen beetle damage in oilseed rape

“…Pymetrozine, tau-fluvalinate and phosmet did not affect the ratio of parasitoids: pollen beetles at the end of the season while thiacloprid and chlorpyriphos-ethyl were found to alter this ratio in the pollen beetles' favour. Reduction of insecticide applications is possible through the use of decision support systems and better use of pest thresholds (Johnen et al 2010;Ferguson et al 2016;Junk et al 2016;Ferguson and Cook 2014). Indeed, in the future, potential for the development of combined thresholds based on multiple pest species, rather than on each pest individually may serve to further reduce insecticide use, as a recent study has shown, counterintuitively, that the interactive effects of high levels of plant damage by seed and stem weevils can lead to increased OSR seed yield, presumably due to plant overcompensation effects (Gagic et al 2016).…”

Semiochemical-based alternatives to synthetic toxicant insecticides for pollen beetle management

“…Non-host-plant odour can be used effectively to repel pollen beetles from OSR, however, only if applied before crop infestation, i.e., during immigration flights (Mauchline et al 2013). Understanding and predicting the triggers for these immigration flights (Mauchline et al 2017) is crucial to the effective deployment of this element of the pest control strategy and the use of Decision Support Systems could help to optimise timing of such applications (Johnen et al 2010;Johnen and von Richthofen 2013;Ferguson et al 2016). …”

Temperature‐activity relationships in Meligethes aeneus : implications for pest management

“…They cause feeding damage to flower buds, resulting in bud abscission and loss of yield . Improving the sustainability of pollen beetle management has become an increasingly urgent issue in the light of evidence for overuse of insecticides in their control and the threat posed by widespread insecticide resistance . There is a need for detailed studies on pollen beetle biology and behaviour to underpin the development of robust and practical decision support tools to improve targeting of control methods and stewardship of insecticides…”

“…However, there is a potential conflict between the need for accuracy of risk assessment, the need to inspire confidence in the DSS and the ease of its employment. There is good evidence that many growers do not use existing pollen beetle control thresholds because, as with many decision support tools, they are perceived to be onerous, the labour costs of employing them being significant in the context of the low cost of control chemicals and the potential to tank‐mix them with fungicide applications …”