TY - JOUR

T1 - Development of a pest threshold decision support system for minimising damage to winter wheat from wheat bulb fly, Delia coarctata

AU - Leybourne, Daniel J.

AU - Storer, Kate E.

AU - Berry, Pete

AU - Ellis, Steve

N1 - Funding Information: The authors gratefully acknowledge the Agriculture and Horticulture Development Board (AHDB) Cereals and Oilseeds for funding this project and would like to thank David Lunn, Josh Humphrey and Andrew Moore for carrying out the 2020 surveys and David Lunn, Tom Whiteside, Nicola Rochford for managing the field trials, and Chris Dyer for statistical support. D. coarctata

PY - 2021/12/29

Y1 - 2021/12/29

N2 - Wheat bulb fly, Delia coarctata, is an important pest of winter wheat in the UK, causing significant damage of up to 4 t/ha. Accepted population thresholds for D. coarctata are 250 eggs/m2 for crops sown up to the end of October and 100 eggs/m2 for crops sown from November. Fields with populations of D. coarctata that exceed the thresholds are at higher risk of experiencing economically damaging infestations. In the UK, recent withdrawal of insecticides means that only a seed treatment (Signal 300 ES) is available for chemical control of D. coarctata; however, this is only effective for late-sown crops and accurate estimations of annual population levels are required to ensure a seed treatment is applied if needed. As a result of the lack of postdrilling control strategies, the management of D. coarctata is becoming reliant on nonchemical methods of control. Control strategies that are effective in managing similar stem-boring pests of wheat include sowing earlier and using higher seed rates to produce crops with greater pest tolerance. In this study, we develop two predictive models that can be used for integrated D. coarctata management. The first is an updated pest level prediction model that predicts D. coarctata populations from meteorological parameters with a predictive accuracy of 70%, a significant improvement on previous prediction models. Our second model predicts the maximum number of shoots for a winter wheat crop that would be expected at the terminal spikelet development stage. This shoot number model uses information about the thermal time from plant emergence to terminal spikelet, leaf phyllochron length, plant population and sowing date to predict the degree of tolerance a crop will have against D. coarctata. The shoot number model was calibrated against data collected from five field experiments and tested against data from four experiments. Model testing demonstrated that the shoot number model has a predictive accuracy of 65.7%. The foundation for a future decision support system using these models for the sustainable management of D. coarcata risk is described. It should be noted that these models represent a stepping-stone towards a decision support system and that further model validation over a wider geographic range is required.

AB - Wheat bulb fly, Delia coarctata, is an important pest of winter wheat in the UK, causing significant damage of up to 4 t/ha. Accepted population thresholds for D. coarctata are 250 eggs/m2 for crops sown up to the end of October and 100 eggs/m2 for crops sown from November. Fields with populations of D. coarctata that exceed the thresholds are at higher risk of experiencing economically damaging infestations. In the UK, recent withdrawal of insecticides means that only a seed treatment (Signal 300 ES) is available for chemical control of D. coarctata; however, this is only effective for late-sown crops and accurate estimations of annual population levels are required to ensure a seed treatment is applied if needed. As a result of the lack of postdrilling control strategies, the management of D. coarctata is becoming reliant on nonchemical methods of control. Control strategies that are effective in managing similar stem-boring pests of wheat include sowing earlier and using higher seed rates to produce crops with greater pest tolerance. In this study, we develop two predictive models that can be used for integrated D. coarctata management. The first is an updated pest level prediction model that predicts D. coarctata populations from meteorological parameters with a predictive accuracy of 70%, a significant improvement on previous prediction models. Our second model predicts the maximum number of shoots for a winter wheat crop that would be expected at the terminal spikelet development stage. This shoot number model uses information about the thermal time from plant emergence to terminal spikelet, leaf phyllochron length, plant population and sowing date to predict the degree of tolerance a crop will have against D. coarctata. The shoot number model was calibrated against data collected from five field experiments and tested against data from four experiments. Model testing demonstrated that the shoot number model has a predictive accuracy of 65.7%. The foundation for a future decision support system using these models for the sustainable management of D. coarcata risk is described. It should be noted that these models represent a stepping-stone towards a decision support system and that further model validation over a wider geographic range is required.

KW - agronomy

KW - crop modelling

KW - crop tolerance

KW - insect pests

KW - integrated pest management

KW - modelling

KW - pest forecasting

UR - http://www.scopus.com/inward/record.url?scp=85111529664&partnerID=8YFLogxK

U2 - 10.1101/2021.03.13.435242

DO - 10.1101/2021.03.13.435242

M3 - Article

AN - SCOPUS:85111529664

VL - 180

SP - 118

EP - 131

JO - Annals of applied biology

JF - Annals of applied biology

SN - 0003-4746

IS - 1

ER -