Population Dynamics of Pieris brassicae (Pieridae: Lepidoptera) on Different Cauliflower (Brassica oleracea L. var. botrytis L.) Genotypes

Aim: The aim of our study was to evaluate commercially available cauliflower genotypes against Pieris brassicae (Pieridae: Lepidoptera) infestation. This would be helpful in evolving resistant varieties of cauliflower (Brassica oleracea L. var. botrytis L.) against P. brassicae.

Study Design: The experiment was laid out in Randomized Complete Block Design (RCBD) with three replications.

Place and Duration of Study: was conducted at the Agricultural Research Institute Tarnab, Peshawar during 2012-2014.

Methodology: To study on Population dynamics of Pieris brassicae (Pieridae: Lepidoptera) ten cauliflower genotypes, i.e. White corona, Snow mystique, Snow grace, Local, Clima, 5340, Sydney, Snow crown, White magic and AX-2034 was used. The treatments were regularly inspected for appearance of pest and data was recorded weekly from appearance of larvae till harvest of crop. In each treatment, five healthy plants of uniform size were randomly selected for data recording. Total number of larvae on upper and lower leaf surfaces was calculated as larvae plant-1. The weight of cauliflower fruits (curd) for each genotype was recorded separately after each picking and total yield was calculated by adding the yield from all picking for each treatment.

Results: The results of field experiments revealed that maximum larval poulation of Pieris brassicae per plant were recorded on White magic (361.83 larvae plant-1) and lower on White corona (15.83 larvae plant-1). And no larvae were recorded on Sydney and AX-2034. Population trend of P. brassicae larvae on cauliflower genotypes during 2012-13 greatly fluctuates between 22nd Nov to 14 Feb. During 2013-14, it gives 3 maximum peaks between 11 Oct to 21 Feb. Mean yield of cauliflower for the year 2012-14 was significantly higher in White Magic (46550 kg ha-1 ) and lower in White Corona (9913 kg ha-1).

Conclusion: It is concluded that all heighted genotypes have more larval population then short height genotypes. White magic was proved itself as a tolerant genotype having more Pieris brassicae larval population per plant but give maximum yield too.