Population Dynamics on The Main Faba Bean Insect Pests in Relation to Certain Ecological Factors in Kafr El-Sheikh Region, Egypt.

Abstract

Field experiments were conducted at Kafr El-Sheikh governorate, Egypt, in 2020-2021 and 2021-2022 seasons to study the population dynamics of certain insect pests infesting faba bean plants namely Liriomyza trifolii (Burgess); Aphis craccivora (koch) and Empoasica spp. In addition, the impacts of certain weather and biotic factors on the population density of the previously mentioned pests. Liriomyza trifolii population density increased in January and March (7.5 and 8.2 larvae/25 leaflets) in 2021 and 2022, respectively. The highest population of nymphs and adults of Empoasca spp in the first season were 6.8 individuals on the 20 th of February, while, in the 2022 season the population density was higher at the end of the season during April and recorded 18 individuals/ 5 plants. For results of the simple correlation in 2021 season, Liriomyza trifolii insects were insignificant with the weather, and biotic factors, whereas, in the 2022 season the relationship was significant with R.H%, wind velocity and plant age. The percentage of explained variance was 38 and 84 % during the two seasons, respectively. For Empoasica spp, in the first season, the population of insect density was significantly correlated for minimum temperature, while, in 2022 season population was significant with RH% and predators. Plant age was a significant effect on the population fluctuations of A. craccivora and Empoasica spp during the second season. The percentage of Explained variance for the effect of climatic factors, and biotic factors on Empoasica spp were 75 and 74 % during the two seasons, respectively. This research aims to utilize the obtained results in developing the IPM programs against the main faba bean insect pests through activation of the effect of temperature, relative humidity and wind velocity on insect numbers.