Cadmium (Cd) is one of the most harmful heavy metal pollutants in aquatic environments. Fingerlings of Nile tilapia, Oreochromis niloticus, were exposed to sublethal concentrations (10, 20 and 30% of the 96-h LC50) CdCl2 which caused significant changes in concentration dependent manner in the hepatic and ileal tissues. The hepatic tissue lost its characteristic architecture, with increased vac...

Using standard WHO methodology, this study investigated the susceptibility of 4th instar Aedes aegypti (L) and Culex annulirostris (Skuse) larvae to three extracts from Callitris glaucophylla (J. Thompson & L. Johnson) (1: steam distillation extract, 2: liquefied refrigerant gas extract, and 3: methanol reflux extract), lambda-cyhalothrin (a synthetic pyrethroid insecticide) and fenitrothion (a...

Susceptibility of Alphitobius diaperinus (Panzer) (Coleoptera, Tenebrionidae) to cypermethrin, dichlorvos and triflumuron in southern Brazil. The lesser mealworm, Alphitobius diaperinus (Panzer), is an important insect pest in poultry houses in Brazil. Susceptibility of the lesser mealworm collected from eight poultry houses in Paraná state, southern Brazil, was evaluated for cypermethrin, dich...

A larval immersion bioassay was developed to identify susceptibility of onion maggot, Delia antiqua (Meigen) (Diptera: Anthomyiidae), to chlorpyrifos and to determine whether this assay could be used to predict control in onion fields. Laboratory colonies were established from larvae collected in New York onion fields during 2003 and 2004, providing us with test insects to use in bioassays. The...

Pyriproxyfen, a juvenile hormone analog insect growth regulator (IGR), is a recommended insecticide for the control of container-inhabiting mosquitoes. The effects of eight container substrates (three plastics, wood, tire rubber, clay pot, concrete, and glass) were studied on reduction of bio-efficacy of pyriproxyfen for Aedes albopictus (Skuse) in the laboratory. Insect growth regulator-bioass...

Baseline toxicity levels to foliarly applied spirotetramat were established for 19 field populations of whiteflies, Bemisia tabaci (Gennadius) B biotype (=Bemisia argentifolii Bellows & Perring) (Hemiptera: Aleyrodidae) from Arizona and California in 2008 and 2009. The susceptibility data were determined against the second instar of B. tabaci field collections before the registration and widesp...

It has become common practice in many laboratories in Europe to introduce the criterion "moribund" to reduce the suffering in fish acute lethality tests. Fish with severe sublethal symptoms might be declared moribund and are removed from the test as soon as this occurs (premature discontinuation of experiment). Moribund fish affect main study outcomes as the median lethal concentration (LC50) d...

Spilanthus acemella Murr. also known as toothache plant is investigated for its preliminary phytochemical analysis and molluscicidal activity. The water extract found maximum extractive value (3.730%) than other solvents used. All the tested metabolites were qualitatively present in ethanolic extract and aqueous extract. Different concentrations of plant parts (root stem, leaf) were used for mo...

The aim of the present study was to observe the effect of seasonal variations (abiotic factors) on the toxicity of carbaryl to L. acuminata. In each month during the year 2006-2007, the 24h LC50 values of the molluscicide carbaryl were determined in an out-door study with the snail Lymnaea acuminata, with concomitant estimation of levels of abiotic factors viz., temperature, pH, dissolved oxyge...