Impact of Sowing Dates and Relation to the Population of Aphis craccivora (Koch) on the Broad Bean (Vicia faba L.) under Climate Changes.

The aim of the study was to evaluate the effect of sowing dates and their relation to the population density of Aphis craccivora (Homoptera: Aphididae) and its associated predators with the effect of weather factors. The Field experiments were conducted at Qaha city, Qalyubiya Governorate, during the winter seasons 2021-2022 & 2022-2023 on the Spanish broad bean, (Vicia faba L.) cultivar. Three sowing dates on the 15th of November (Recommended); the 1st of December and the 15th of December during winter cultivation were evaluated. Results showed that the sowing date of 15th December in the first and second winter seasons was the preferable date for sowing. Where the lowest general mean numbers of A . craccivora were 21.25 ± 1.80& 24.01 ± 1.29 individuals/two successive seasons, with higher productivity recorded 980.15 ± 43.46 & 1000.00 ± 38.93 Kg./two seasons, respectively. while, the highest general mean numbers of A. craccivora for sowing dates on the 15th of November and 1st of December were 46.09 ± 2.52 & 48.85 ± 2.75 and 41.34 ± 2.43 & 43.57 ± 1.87 individual/two seasons, respectively. Also, the lower productivity on the 15th of November and 1st of December were 538.8 ± 33.46 & 590.60 ± 24.62 and 680.00 ± 43.41&646.71 ± 26.50 Kg. for two seasons. Statistical analysis showed that there were highly significant differences between the sowing date on the 15th of December and each of the sowing dates on the 15th of November and the 1st of December. Also, there were no significant differences between the sowing dates on the 15th of November and the 1st of December. Furthermore, showed result the effect Plant ages, Natural enemies, Temperature, R.H.% and wind speed had different effects (significant or insignificant) on the population A. craccivora. [ABSTRACT FROM AUTHOR]

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