To provide the using information of disinfectors dose in the tobacco float seedling system,the efficacies of 90% lethal dose(EC90) of 10 disinfectors were examined by carrier germicidal test on breeding substrates,including polystyrene foam trays,polyvinyl chloride plastic film and stainless blade which were inoculated with Ralstonia solanacearum.

At same time, we also knew the LD100 of konjac is 3KR and LD50 is 1.

Effects of sub-lethal dosages abamectin on food intake and digestive enzyme activities of silkworm Bombyx mori L.;

Toxicity of emamectin to larvae of the diamondback moth, Plutella xylostella, at different temperatures was surveyed, and the effects on survivors of parent generation treated with sub-lethal dosage of the insecticide at 25℃ were studied with life table method.

to 10 antibiotics: gentamicin,neomycin, ampicillin,kanamycin,cephalothin,streptomycin,G418,hygromycin Zeocin and chloramphenicol were investigated.

Moreover,the higher dose,the higher death rate,and the Half Lethal Dosage(LD50)for the seedlings of 41 days was 150 Gy.

The result showed that the stronger was radicalization,the larger was restrained degree;the sensitivity of different varieties were different; the LD50 of adventitious buds was 30-40GY, the LD50 of the calli was 10-20GY.