title: Influence of cypermethrin and fenvalerate on a green alga and three cyanobacteria isolated from soil.
abstract: The effects of two pyrethroid insecticides, cypermethrin and fenvalerate, on a green alga (Scenedesmus bijugatus) and three species of cyanobacteria (Synechococcus elongatus, Nostoc linckia, and Phormidium tenue), all isolated from a black cotton soil, were studied using either cell number or chlorophyll a as toxicity criterion. All the four species were either unaffected or stimulated at 5 micrograms ml-1. Of the two insecticides, cypermethrin, at 10 to 50 micrograms ml-1, inhibited S. bijugatus while these concentrations stimulated or only slightly inhibited the growth of S. elongatus. There was a significant inhibition in the growth of S. bijugatus and stimulation in S. elongatus with 10 to 50 micrograms ml-1 fenvalerate. The growth of N. linckia was enhanced by both insecticides while P. tenue was significantly affected.
mesh_terms: D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D000460:Chlorophyta / Q000187:drug effects*; D000458:Cyanobacteria / Q000187:drug effects*; D007306:Insecticides / Q000633:toxicity*; D009570:Nitriles; D011722:Pyrethrins / Q000633:toxicity*; D012988:Soil Microbiology
chemical_list: D007306:Insecticides; D009570:Nitriles; D011722:Pyrethrins; D002734:Chlorophyll; C017160:cypermethrin; D000077194:Chlorophyll A; C017690:fenvalerate