Study on the Co-toxicity of Mixtures of Alkaloid from Aconitum Flavum Hand.-Mazz. and Several Kinds of Plant Against Plutella Xylostella
|Keywords||Acontium flavum Hand.-Mazz. Alkaloids Co-toxicity Plutella xylostella Wateremulsion|
Aconitum flavum Hand.-Mazz. was used as folk medicine commonly, the researches about its pharmacological was appeared a lot, in recent years, the studies of its insecticidal activities and the active ingredients were appeared, unfortunately, results indicated that a single dose of the crude extract from Aconitum flavum Hand.-Mazz. had not high activity. Therefore, in this article, the insecticidal activities of crude extract and alkaloids from Aconitum flavum Hand.-Mazz. were studied firstly, then, alkaloids from Aconitum flavum Hand.-Mazz. were mixed with alkaloids from other plants, and the allied toxicity of the mixture of alkaloids were measured in laboratory. After that, the compound with synergy effect were screened by three evaluation methods. Then, this appropriate compound was developed into water emulsion by putting in the appropriate solvent and emulsifier. Finally, safety evaluation by indoor simulated tests and the field experiments had been conducted. The main contents and results were obtained as follows:1. Comparison of insecticidal activities between wild and cultivated Aconitum flavum Hand.-MazzThe insecticidal activities against Plutella xylostella of crude extracts and alkaloids from wild and cultivated Aconitum flavum Hand.-Mazz. were compared. The results showed that the insecticidal activities of wild Aconitum flavum Hand.-Mazz. were similar to cultivated Aconitum flavum Hand.-Mazz. So, the cultivated Aconitum flavum Hand.-Mazz was used as mainly raw material in this article.On the other hand, the insecticidal activities against Plutella xylostella of the alkaloids were stronger than crude extracts, therefore, the alkaloids were the main insecticidal activity ingredients of Aconitum flavum Hand.-Mazz.2. The co-toxicity of mixtures of the alkaloids from Aconitum flavum Hand.-Mazz. with several alkaloids from several other plantsThe toxicities of mixtures of alkaloids from Acontium flavum Hand.-Mazz. and other plants such as Cynanchum komarovii and Sophora alopecuroides against Plutella xylostella were researched. The effect of the joint toxicity was assessed by the methods of Bliss, Sun and nonoB respectively. The result showed that three kinds of evaluation results was consistent, and the joint toxicity was higher than single alkaloid.The synergy of the alkaloids mixtures of Acontium flavum Hand.-Mazz.and Cynanchum komarovii was superior to which with Sophora alopecuroides. The co-toxicity coefficient of Acontium flavum Hand.-Mazz. with Cynanchum komarovii was293.82, efficiency index was2.94with the mass ratio3:1.3. Insecticidal activity of alkaloids mixtures against Plutella xylostellaContacting, antifeeding, stomach poisoning and inhibition of growth and development against Plutella xylostella were determined by different activity testing methods. The result showed that, alkaloids distribution showed contacting and antifeeding effects against3th instar larvae obviously, meanwhile, the stomach toxicity and inhibition of growth were weak. When Plutella xylostella were treated with concentration of10.00mg/mL, the cor-rected mortality rate for72h was96.67%, the anti-feeding rate for48h was90.37%, the dpoisoning death rate was90.00%, and growth inhibition rate for48h was89.97%.4. The preparation of EW(emulsion in water) and the toxicological testsolubility, cold and hot storage stability was used as index, cyclohexanone and SongJi ND-60was used as solvent system, and the orthogonal experiment was used to optimize the emulsifier(cyclodextrin, Twain-80.) and co-emulsifier(n-butylalcohol, hexyl alcohol), the EW were optimized as follows:alkaloids mixtures was10%, solvent was20%, emulsifier was11%, co-emulsifier was5%, antifreeze was3%, stabilizer was2%, and tap water was49%. Emulsion stability, low temperature stability and heat storage stability of this EW were qualified by quality control testing.Then, insecticidal activity of this EW against Plutella xylostella and Aphis sp. were tested. The results showed that the cor-rected mortality rate for72h was100%and98.89%under the concentration of5.00mg/mL.5. The field trials and the safety evaluation test of the EWThe field tests of the EW against Plutella xylostella and Aphis sp. were determined. The results showed that the control efficacy of the EW could over95%under the concentration of1.2mg/mL, and keep efficience within15days, which was longer than traditional chemical pesticides such as Abamectin,4.5%Lambda-Cyhabthrin, Malathion and so on.Finally, Carassius auratus, one of the sensitive aquatic organisms was as test target, the safety of the EW against fish was evaluated by static bioassay tests. The results showed that the EW had low toxicity on Carassius auratus with the lethal concentration of50%was6.62mg/mL after96h, therefore, it was safe to aquatic organism and surrounding environment.