Pest incidence on Yardlong bean grown under protected and open field conditions

Abstract

Investigations on incidence of major pests of Yardlong bean grown under protected (polyhouse and shadenet) and open field conditions were carried out during kharif 2016 at ZAHRS, Navile, Shivamogga. The variety used was 'Arka Mangala'. A total of four species of insects and one mite pest was recorded. Insect pests included Tabacco caterpillar (Spodoptera litura), Leaf miner (Liriomyza trifolii) and mite pest Tetranychus urticae (Koch) under polyhouse. In shadenet, L. trifolii, T. urticae (Koch) and black aphid (Aphis fabae) were reported. In open field condition L. trifolii, T. urticae, A. fabae and pod borer (Maruca vitrata) were noticed. Maximum incidence of S. litura (0.91 larvae per plant) was observed at seedling stage under polyhouse and no incidence in other environments. L. trifolii observed under all the three environments but high incidence in shadenet (16.40%). T. urticae was also recorded under all the environments whereas high incidence in polyhouse (24 adults per five leaves). Maximum incidence of M. vitrata (0-10%) was observed only in open field and there is no incidence under polyhouse and shadenet. Maximum incidence of A. fabae (10-25%) damage was noticed in open condition followed by shadenet but no incidence in polyhouse.