The insecticidal activity of Cyanobacteria against four insects, two of medical importance and two agricultural pests with reference to the action on albino mice.

Acute lethal toxicity of Cyanobacteria (blue-green algae) was investigated against 3rd larval stages of Musca domestica, and Culex pipiens, and 4th larval stages of Spodoptera littoralis and Agrotis ipsilon. The LD50s were 1.94, 2.33, 7.59 and 9.10 microg for M. domestica, C. pipiens, S. littoralis and A. ipsilon respectively. The slope functions were 4,045 +/- 0.332 (M. domestica), 4.122 +/- 0.336 (C. pipiens), 4.15 +/- 0.35 (S. littoralis) and 3.72 +/- 0.34 (A. ipsilon). These LD50s markedly affected the larval, pupal and adult time of durations as well as suppressed the oviposition of the survivor adults. The LD50 didn't show any marked effect as serum acetyl cholinesterase and gave nearly the same level of AchE activity. No doubt, Cyanobacteria are safe and promising agent for insect control.