تاثیر اسانس درمنه خزری Artemisia annua L. و دو ترکیب اصلی آن روی لارو شب‌پره ابریشم باف پاییزی Hyphantria cunea (Drury)

The fall webworm, Hyphantria cunea (Drury) (Lepidoptera: Erebidae), is a devastating invasive pest which is native to North America, but is currently widely spread in various parts of Europe and Asia. This pest causes serious damages to local forests, agricultural crops, orchards and urban ornamental trees, resulting in significant economic loss. The sweet wormwood, Artemisia annua L., is a medicinal herb which native to temperate Asia, and has attracted attention due to its numerous biological activities. The chemical components of A. annua essential oil was analyzed by GC-MS and about 71 compounds were identified. The compounds (±)-camphor (16.42%), 1,8-cineole (6.22%), α-pinene (6%), caryophyllene (5.19%), and α-selinene (5.17%) showed the maximal percentage. The aim of this study was to determine topical toxicity of A. annua and its two major components against the third instar larvae of H. cunea. The LD50s were estimated for essential oil of A. annua 305.05, 465.03 and 573.49 μg/larva for essential oil, (±)-camphor and 1,8-cineole respectively. Although both 1,8-cineole and (±)-camphor indicated considerable toxicity when applied individually, the binary mixtures of compounds expressed a weaker activity. The current study jndicated that the mixture of 1,8-cineole and (±)-camphor act antagonistically. In accordance with the role of detoxifying enzymes as well as intermediary metabolism in reducing the effect of used compounds, we studied the effects of lethal and sub-lethals of A. annua essential oil and its two major constituents, on theses parameters. The results indicated a decreasing trend in alanin and aspartate aminotransferase, however the acid and alkaline phosphatase showed an increasing trend. Activity of lactate dehydrogenase was significantly higher than the control group at 24 h, but decreased significantly later (48 h) in all treatments. While the activity of esterases were decreased in the treated larvae but glutathione S-transferase and cytochrome P450 were significantly increased in all time intervals. Overall the current results suggest that the A. annua and its components could be a safe and environmentally friendly approach in possible control of H. cunea.