Surfactant Quantity and Deposit Particle Size Influence Direct Spray and Residual Deposit Toxicity of Chlorpyrifos to Hetiothis punctigera
Authors: MacQuillan, M. J.; Sucksoong, Visutr; Hooper, G. H. S.
Source: Journal of Economic Entomology, Volume 69, Number 4, August 1976 , pp. 492-494(3)
Publisher: Entomological Society of America
Abstract:In laboratory experiments, chlorpyrifos 22.4% wt/wt and 40.8% wt/wt EC both containing 8% wt/wt surfactant and 2 chlorpyrifos 25% wt/wt WP, one containing 3% wt/wt and the other 10% wt/wt surfactant were compared for toxicity to 4th instars of Heliothis punctigera (Wallengren). Formulations were diluted appropriately with water and direct spray and residual deposit applications made with a Potter Spray Tower. Each application was of 2 ml at 60 cm Hg pressure. The LC50 of 0.0419% wt/vol 48 h after direct spray application for the EC having the higher ratio of surfactant to active ingredient was significantly lower than 0.0521% wt/vol for the EC having the lower ratio. The LC50 of 0.0523% wt/vol 48 h after direct spray application for the wp having the higher ratio of surfactant to active ingredient was significantly lower than 0.0844% wt/vol for the wp having the lower ratio. After 48 h of exposure to residual deposits the LC50 was 0.0263% wt/vol for deposits of larger particles, ca. 8 μm,given by 40.8% EC significantly higher than 0.0145, 0.0144, and 0.0183% wt/vol for deposits of smaller particles, ca. 4 and 3 μm, given by 22.4% EC and two 25% WP, respectively.
Document Type: Research article
Publication date: 1976-08-01
- Journal of Economic Entomology is published bimonthly in February, April, June, August, October, and December. The journal publishes articles on the economic significance of insects and is divided into the following sections: apiculture & social insects; arthropods in relation to plant disease; forum; insecticide resistance and resistance management; ecotoxicology; biological and microbial control; ecology and behavior; sampling and biostatistics; household and structural insects; medical entomology; molecular entomology; veterinary entomology; forest entomology; horticultural entomology; field and forage crops, and small grains; stored-product; commodity treatment and quarantine entomology; and plant resistance. In addition to research papers, Journal of Economic Entomology publishes Letters to the Editor, interpretive articles in a Forum section, Short Communications, Rapid Communications, and Book Reviews.
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