BIOLOGY AND ABUNDANCE OF THE STRIPED FLEA BEETLE, Phyllotreta striolata (F.) (COLEOPTERA: CHRYSOMELIDAE), ON PAK-CHOI (Brassica campestris var. chinensis L.), AND MANAGEMENT OPTIONS AGAINST THE INSECT PEST

摘要

The biology of the striped flea beetle, Phyllotreta striolata (F.), was studied on detached pak-choi leaves in the laboratory and on potted plants in the net house. Total developmental period was 18.35 ± 0.25 days on detached leaves and 25.86 ± 4.44days on potted plants. Adult longevity was 39.68 ± 14.02 days for male and 36.56 ±11.53 days for female. The mean fecundity was 619.08 ± 148.60 eggs/female. The sex ratio (male:female) was 0.90:1. Of the seven Brassicaceae species tested, pak-choi, Brass/ca campestris var chinensis (L) and Indian mustard, B. juncea (L) were the most preferred host plants, followed by Chinese cabbage, B. pekinensis (Lour.). The least preferred was Chinese kale, B. o/eracea (L.). Among the pak-choi cultivars, Black Behi had the highest damage rating while Ching-Chang and Psai-Tsai had the lowest. Two Cleome weed species (C. viscosa and C. rutidosperma) of the Family Capparidaceae, were likewise fed upon by the beetles. Adult P. striolata although present year round,were most abundant in March. Temperature and rainfall affected their abundance in the field. Lower population to almost nil occurred during the wet months but higher population was present during the warm months. Among the management options evaluated, the most promising were: soil solarization using black or clear polyethylene mulch which significantly decreased the number of larvae and pupae in the soil; netting (32 mesh) which deterred insects from attacking the plants; and mulching with rice straw and rice hull which reduced feeding damage by adult P. striolata. Application of the insecticide fipronil also protected pak-choi plants from any insect pest damage.