Odette R. Farah

Cytological and Morphological Effects of the Insecticide N-methyl-l-naphthyl Carbamate “Sevin”

Summary The present investigation aimed to elucidate the effect of the insecticide “Sevin” on mitosis of Vicia faba and Gossypium barbadense as well as on some morphological aspects of germenation. Germinability of seeds of various crops was decreased by soaking the seeds in a saturated solution of “Sevin”. The decrease in germinability is greater as the time of soaking increases. Root-treatments (0,1 ppm. 100 ppm) as well as seed-soak treatment in saturated solution of the insecticide caused inhibition of primary root-length, and decrease in the percentage of shoot energence of Vicia faba . It was found that the mitotic index of Vicia faba decreased with increase of the concentration of “Sevin” solutions (0,25 sat. “25 ppm.” — sat. soln “100 ppm”) after root-treatments, while soaking seeds in saturated solution for 6—48 hour durations did not show amy significant effect. Abnormalities were induced in the mitosis of Vicia faba and Gossypium barbadense after “Sevin” application. The percentage of these increased with concentration and length of treatment.

The Effect of 1-Naphthyl-n-Methyl Carbamate “Sevin” on Germination, Growth and Yield of Cotton Plant

Summary The effect of the insecticide 1-naphthyl-n-methyl carbamate “Sevin” on cotton plant was studied. Soaking of seeds in saturated solution for different periods (one to three days), was followed by inhibition of seedling emergence, plant growth and yield. Spraying with saturated and 0.5 saturated solutions of “Sevin”, applied weekly or every other week, did not show any injurious effect but slight inhibition of foliar growth in some cases. Enhancement of flowering and fruiting was reported by a weekly spray application with saturated and 0.5 saturated solutions. This was followed by a higher degree of fruit abscission and higher yield (Lint, seed, and lint seed/plant) than the control. This effeet was attributed to the thinning of the plants.