Prediction of Tuta absoluta (Meyrick) Generations Using Cumulative Degree-Days Model

Abstract

Faskha, S.M., R. Darwish and A. Dayoub. 2022. Prediction of Tuta absoluta (Meyrick) Generations Using Cumulative Degree-Days Model. Arab Journal of Plant Protection, 40(4): 299-306. https://doi.org/10.22268/AJPP-40.4.299306 The seasonal changes in the population density of tomato leafminer, Tuta absoluta, and its relationship to cumulative degree-days was studied using a sex pheromone trap in a plastic house located in Tartous Governorate, Syria during the spring season of two successive years 2020 and 2021. The results obtained showed that the male T. absoluta activity extended from late February to the end of the season in July. The highest density for males recorded in May was 207 and 213 males/trap in both seasons, respectively. The calculation of the cumulative degree-days showed that the insect has five generations with a thermal constant that reached in the first season: 516.95, 510.24, 512.2, 563.44, 565.94 DD for each generation, respectively, and in the second season 554.52, 533.06, 557.21, 502.55, 508.22 DD for each generation, respectively, without significant differences between the two seasons (x² = 6.02, p = 0.2 and x² = 4.94, p = 0.29). However, according to the model followed, a simplified table was proposed to calculate the cumulative degree-day instead of using mathematical models, based only on the daily maximum and minimum temperatures. Keywords: Tuta absoluta, degree-days, generations, Tartous, Syria