Toxicity of a Neem (Azadirachta indica) insecticide to certain aquatic organisms.

Neem based insecticides are likely to show a large increase in use in the near future. In the present work, the toxicity of a neem insecticide, Neem-Azal-T/S, was tested against the mosquito larvae, as well as against certain non target organisms occurring in a polluted pond and a shallow stream, located in a cultivated area in Giza, Egypt. Samples of water containing the experimental animals were collected from this area, and toxicity tests were conducted in the laboratory by exposing them to a series of concentrations of the botanical insecticide, using the water of the pond and stream at room temperature (28-31 degrees C). The compound was more or less toxic to all the tested species. The LC50S and mortality rates were determined. The order of tolerance of the organisms to different concentrations of the insecticide was: larvae of Bufo regularis (Amphibia) > Aedes caspius. (Insecta) > Gambusia affinis (Poeciliidae) > Cyclops sp. > Daphnia magna (Crustacea). At a concentration of 20 ppm, all the tadpoles died within 9 days, while all other individuals died within 5 to 8 days after exposure to a concentration of 10 ppm of Neem Azal insecticide.

Toxic effect of ethanolic extract of Nerium oleander (Apocynaceae) leaves against different developmental stages of Muscina stabulans (Diptera-Muscidae).

Nerium oleander (Apocynaceae) is evergreen shrubs widely used for ornamental purpose in mediterranean region. The present investigation, revealed for the first time the insecticidal effect of ethanolic extract from leaves of this plant against 2nd instar larvae of the medically important false stable fly Muscina stabulans (Diptera: Muscidae). LC50 of the extract was 113.66 ppm. This dose delayed larval and pupal duration suppressed oviposition and decreased adult longevity of the survivors. Morphogenic abnormalities were recorded and photographed in larval, pupal and adult stages, which were produced from treating 2nd instar larvae with different concentrations of the extract.

Protective role of soybean feeding against the cytogenetical and histopathological effects of dibutylamine and sodium nitrate on bone marrow and liver of mice.

The protective role of soybean feeding against the cytogenetic and histopathologic effects of the nitrosamine precursors sodium nitrate and dibutylamine was evaluated. Treated animals were killed every 3 months, over a period of 15 months, and bone marrow cells were prepared for cytogenetic studies and livers for histopathological observations. Structural chromosomal aberrations and mitotic indices increased after treatment with the nitrosamine precursors for all tested times. Livers were within the normal appearance during the first 6 months. After that a mild, moderate, marked dysplasia with lymphocytic infiltration, fatty vacuolation and liver atrophy was observed. Soybean coadministered with the nitrosamine precursors reduced the number of structural chromosomal aberrations. Mitotic indices decreased at all tested groups but still higher than the control level. A marked reduction in dysplastic features in the liver cells was observed. In conclusion, the cytogenetic and histopathologic results of this study strongly support the protective role of soybean against the genotoxic and carcinogenic action of nitrosomine formed in vivo from its precursors.