ISHS Acta Horticulturae 525: International Conference on Integrated Fruit Production
INTEGRATED CONTROL OF ORIENTAL FRUIT MOTH, GRAPHOLITA MOLESTA, ON PEACHES USING A SPRAY-DATE PREDICTION MODEL |
| Authors: | T.L. Blomefield, B.N. Barnes |
| Keywords: | oriental fruit moth, peaches, phenology model, degree-days, spray-date prediction service |
| Abstract:
Oriental fruit moth, Grapholita molesta Busck., is the most serious pest on peaches in the Western Cape Province. Control initially comprised up to 13 insecticide applications per season. This excessive insecticide programme disrupted non-target arthropod fauna, necessitating the application of additional expensive acaricide sprays. In order to optimize G. molesta control actions and reduce their impact on the orchard environment, a degree-day phenology model for G. molesta is being used to pinpoint spray dates that provide optimum control with the minimum number of insecticide applications. G. molesta pheromone trapping data from up to 18 different peach production areas is sent weekly to INFRUITEC. This data is used to determine the "biofix" (calendar date of the first sustained moth emergence) for each generation in each area. Maximum and minimum temperatures from weather stations in each production area are used by INFRUITEC to calculate the number of cumulative day-degrees from the biofix of each generation. According to the prediction model, the optimum spray-window for each generation occurs between 278 and 333 degree-days after the biofix, when the maximum number of neonate larvae will be exposed to a single insecticide application. The optimum spray dates for each generation in each production area are calculated weekly and made available to growers on a telephone answering machine. A maximum of five insecticide applications per season, applied according to the phenology model, now effectively control G. molesta. Use of this G. molesta spray-date prediction service has, therefore, reduced insecticide usage against this pest by more than 50%. Accordingly, acaricide applications have been reduced. Savings in costs to the peach industry amount to an estimated R1.3 million per year. | |
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