Control strategy for maize wallaby ear symptom based on a quantitative forecasting model for the maize orange leafhopper, Cicadulina bipunctata

Abstract

The maize orange leafhopper (Cicadulina bipunctata) induces maize wallaby ear symptom (MWES) in forage maize in temperate southwest Japan. Using 10 years of field data (2004–2013), we developed a forecasting model for C. bipunctata based on climate and density factors that can guide the minimum level of control required to prevent MWES. The multiple regression analysis selected both temperature and precipitation from the previous winter to summer and maximum C. bipunctata density in the previous August as determinant factors in the model for forecasting occurrence of C. bipunctata in summer. This forecasting model could predict C. bipunctata occurrence with an accuracy of <1 averaged standardized residuals, supporting the validity of the model. Economic levels of injury due to MWES in susceptible and tolerant (resistant) maize varieties were sustained at densities of 21 and 74 adults/m2 respectively, derived from the results of suction and light trap monitoring of C. bipunctata in the field. Combining these economic injury levels and the forecast from the model can guide choice of crops/varieties and seeding period in the coming summer to prevent MWES injury. This forecasting system is expected to be implemented in southwest Japan after consideration of the adaptability of the forecasting model to the entire target area.