Role of natural enemies, climatic factors and performance genotypes on regulating pests and establishment of canola in Egypt

Abstract

Screening twenty available advance lines of canola plant based on population density of the recorded pests throughout 2011 and 2012 seasons at Ismailia Agricultural Research Station Farm, Egypt was studied. The cabbage aphids; Brevicoryne brassicae , thrips; Thrips tabaci , diamondback moth; Plutella xylostella, leafminer; Liriomyza sp. , whitefly; Bemisia tabaci and two-spotted spider mite; Tetranychus urticae were surveyed pests in canola. Six predacious species related pests; Coccinella septempunctata, Coccinella undecimpunctata, Stethorus gilvifrons , Chrysoperla carnea, Syrphus corollae and Orius spp. Diaretiella rapae, Cotesia plutellae and Diadegma inslare were the most common parasitoids emerging from the collected samples. The analysis of variance revealed significant variation among dates of observations, lines and in their interaction for all surveyed pests and their natural enemies. The percentage of explained variance of abiotic factors (minimum–maximum temperatures and relative humidity) and biotic factors (predators and parasitism percentages) altogether in the population densities of B. brassica , T. tabaci , P. xylostella, Liriomyza sp. , B. tabaci and T. urticae in the second season were the greater percentage values as 87.0%, 94.7%, 88.9%, 70.1%, 63.2%, and 68.3%, respectively, compared to the first season (60.4%, 89.6%, 47.7%, 31.1%, 45.5% and 69.8% respectively). Mean performance of agronomic characters, phenotype’s coefficient of variation (PCV), genotype’s coefficient of variation (GCV), environmental coefficient of variation (ECV), heritability (Hb) and genetic advance (GS%) for yield and its attributes in canola genotypes were also studied. These results could be involved in breeding programme cultivated to improve future integrated pest management programme of canola in Egypt.