Pyrethroid-induced resurgence of sucking pests in the mango eco-system.
Sushil Kumar, Bhatt R. I.
Author Affiliation: Agriculture Experimental Station (AES), Gujarat Agricultural University, Paria, Valsad, Gujarat - 396 145, India.
Journal of Applied Zoological Researches 13 : 107-111
Abstract : Resurgence induction of the sucking pests (hopper and thrips) by four synthetic pyrethroids viz., cypermethrin (0.003%), fenvalento [fenvalerate] (0.01%), deltamethrin (0.00075%), and alphamethrin [?-cypermethrin] (0.003%) and organophosphorus insecticides viz. monocrotophos (0.05%), methyl-o-demeton [demeton-O-methyl] (0.05%), and dimethoate (0.03%) and their toxicity on natural enemies viz. Menochilus sexmaculutus [Cheilomenes sexmaculata] and the spider, Plexippus paykulli, were studied in a mango garden at AES, Paria, Gujarat, India. First insecticide application was made at flowering initiation and subsequent applications were done twice at monthly intervals. Monocrotophos (0.05%) effected a slight population buildup of planthoppers after 30 days of spraying. Results of methyl-o-demeton, dimethoate and control treatments were similar. Initially, the pyrethroids significantly reduced the pests but registered resurgence at 30 days after treatment. The synthetic pyrethroids were toxic to the coccinellid predator, Menochilus sexmaculata and the predatory spider, Plexippus paykulli, but organophosphate treatment recorded higher population of these beneficial insects.