Probability analysis of pheromone trapping for olive moths, prays oleae Bern. (Lepidoptera: Yponomeutidae) and a regional decision-making algorithm for spraying for fruit generation

Abstract

This study designed an algorithm for regional optimum spray timing to prevent damage to olive trees by the olive moth (Prays oleae Bern), which is the primary pest of olive orchards in several regions with land borders within Edremit Bay, Balikesir Province, Turkey. Olive moth populations were monitored using delta-type pheromone traps containing (Z)-7-tetradecenal in nine olive orchards in three Edremit Bay districts between 2020 and 2021. The density of the traps was one per orchard. All the traps were checked weekly between April 2020 and December 2021. The number of moths per trap was recorded in each orchard. To determine fruit damage, 200 olives were sampled randomly from each orchard and examined under an optical microscope. The eggs, emerged larvae, and larval entrance holes in the fruits were recorded. The scatter of the obtained data was analyzed using a two-parameter Weibull distribution. The weekly infestation rates in cases with high catch probabilities were determined to be between 50 and 99%. To reach the economic damage threshold of 10% (egg in the fruit + larva + larva entry hole & GE; 10%) recommended by the Ministry of Agriculture and Forestry of the Republic of Turkey, in order to determine time of spraying, the threshold of the number of moths caught per daily trap was determined between 9 and 12. In this study, an algorithm for optimum spray timing, including 15 d meteorological weather forecasts, such as average daily temperature, relative humidity, and wind speed, was proposed for region-specific reduction of fruit damage.