Study On The Effects Of Yuan-hua Active Components To Digest Enzymes And GST Of Two Lepidoptera Larvae

Laboratory experiments show that yuan-hua (Daphne genlcwa) alcohol crude (YAE) and P -sitosterol have a strong effect on restraining feeding and growth of the larvae of Spodoptera laura and Abraxas miranda. They also can increase the activity of digest enzymes and GSTs, but for the later is decreased to the control level at late period. The 4instar Spodoptera litura larvae growth weight is only 34.50% of the control after it eats the leave treated with 10% YAE ld, after 4d the rate only 6.73%, that is, the weight growth-rate decreased 93.27% than the control. After eating the leaves, the 5tll~instar larvae th pupation to be advanced, pupating, emerging and body weight decreased,. After the 2 -instar larvae had been raised with treated leaves for 3-Sdays, the body decreased strikingly, but the modality was only 3.3%. It shows that the kill effect is not very strong. di The 4 -instar Spodoptera litura larvae feeding capacity and weight growth rate were 66.0 1% and 68.14% of that of the control, respectively, after eating the leaves treated with 0.1% P -sitosterol for 48h. the effect differs significantly to the control, although the level is inferior to YAE. The 4instar Spodoptera laura and Abraxas miranda larvae digestive enzymes(amylaes,esteraes,proteinase) activity ndex are all higher than that of the control after they had eaten the leaves treated withlo% YAE for continuous 4-days; eaten the leaves treated with 0.1% P -sitosterol for continuous 4-days, the activity ndex of amylase is significantly higher than that of the control, but the activity of amylaes and proteinase are almost the same to the control. The activity of GSTs is increased much high than the control after the 4t%nstar Spodoptera litura larvae eating the leave treated with 10% YAE for 4d. After the 4diinstar Spodoptera litura larvae had eaten the leave treated with YAE for continuous 3 generation, 4d per generation, the activity of GSTs enhanced in F0-F1 generation, and than decreased in F2 to di the level of the control. After the 5 -instar Spodoptera laura larvae were raised on the same condition for continual 3 generation, the activity of GSTs enhanced firstly then went down, but the difference is not significant Primary experiment results seen show that the tendency of Spodoptera litura larvae accumulate resistance to yuan-hua toxin is not significant when it raised on for continual 3 generation. Respiratory activity of 3 diinstar Spodoptera laura larvae is the same of that of the control after the larvae had eaten the leave treaded with 10% YAE for 2d. The active components of yuan-hua not only inhibits the insects eating capacity but also promotes the over-secretion of digest enzyme and GST5 which over-consumed the nutrition and energy, at last the resulted in the insect gradually exhausting and death.