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The Inducting And Using Of Dendrolimus Superans (Lepidoptera: Lasiocampidae) To The Volatiles Of Larix Gmelinii

Posted on:2007-10-11Degree:MasterType:Thesis
Country:ChinaCandidate:Y S LiuFull Text:PDF
GTID:2133360185455146Subject:Forest protection
Abstract/Summary:PDF Full Text Request
Dendrolimus superans is one of important pests in northeast woodland in China, which endanger Larch, Korean pine, Chinese pine and Mongolian Scotch pine. When the pests break out, they can eat up leaves of the conifers, make limbs exposed as being fired, even blast many pines at great superficial extent. Consequently, they can cause serious harm to forestry production. The chemical methods give still priority to the way to prevent and control the pest. In recent years, with the development of insect chemical ecology, using plant secondary materials and those substances which are extracted and separated from plants or their products with biological activity to regulate pests action and to control hazard has become the worldwide trend in Insect Comprehensive Treatment.In this study, we found out that the volatile compounds of Larix gmelinii are main terpenes such as α-pinene, β-pinene, β-ocimene, camphene, phellandrene, phytol, myrcene and so on. and the variety of these volatile compounds release quantity after cutting leaves and eaten by Larix gmelinii. The release quantity is go up in the 2 hours after injury, then declined. At the 12 hours of after injury, the release quantity of injury with cutting 25% leaves is the half to the healthy plant, the release quantity of injury with cutting 50% leaves is the same to the healthy plant.The amount of release of these volatiles changed due to the effects of external factors and the change will last for a period. The amount of β-phellandrene, camphene and 3-carene increased significantly after the plants were damaged by artificial mechanical injury, while no obvious changes occurred in the amount of ocimene, β-myrcene, α-phellandrene and 4-carene, but α-pinene decreased. When the plants were damaged by dendrolimus superans, the increase of 3-carene and β-myrcene were the most remarkable, the release of ocimene, β-phellandrene and camphene had no obvious changes, while those of β-pinene, α-phellandrene and 4-carene decreased, the changes of these volatiles approached the level of normal plant 12 hours later. At the same time we measured EAG response to 9 volatiles such as R-α-pinene, S-α-pinene, ocimene, S-β-pinene, phellandren, camphene, phytol, myrcene, 3-carene and so on in Dendrolimus superans. The value of EAG increased with growing of concentration of volatiles and decreased when the concentration reached the maximum. According to variance analysis and Duncan multiple comparison, the response of no mating female moths for 9 compounds in 7 different concentration is different significantly from that of male moths (p<0.05) and the response of mating female moths is different terribly from that of no mating both sexes of moths (p<0.01).The order of EAG response to 0.1μL·μL~-1 phellandrene is no-mating female moths>mating female moths>no-mating male moths and the order of EAG response to otherdifferent compounds of various concentration is mating female moths>no-mating female moths>no-mating male moths. It showed that these semiochemicals are very important for oviposition preference in Dendrolimus superans. Simultaneously, we found that Dendrolimus superans had orientation toward S-a-pinene, P-pinene, phellandrene and phytol while R-a-pinene, P-ocimene, camphene, myrcene and 3-carene showed evading trend according to behavioral biology experiments. In ovipositing choice experiments of adult moths, the oviposition of most of mating female moths gave priority to health plants, and account for 82.3% to toatal oviposition . Among plants with various degree injury, they selected lightly injured plants to oviposit. In the experiment of insect injured plants mixed with mechanical injured plants, The quantity of oviposition on mechanical injured plants was larger than on insect injured plants.The antennas of Dendrolimus superans were observed through scanning electron microscopy and paraffin section. We found 5 kind of antenna sensilla which are sensilla trichodea, sensilla chaetica, sensilla coeloconica, sensilla sensilla sprout-shaped and sensilla cavity-shaped. Sensilla trichodea was the most of them, which were mainly located on the inboard antennas and windward side. A small quantity of sensilla coeloconica, sensilla chaetica and sensilla cavity-shaped were situated on the lateral side of antennas and antennal axis. And the total number of sensilla in the male moths was larger than in the females. We found that eggs of 92.4% were laid on the ground and net, and only 7.6% were laid on plants when their antennas were cut off. It showed that olfactory sensilla are mainly located on the antenna in Dendrolimus superans.
Keywords/Search Tags:Dendrolimus superans, Larix gmelinii, Volatile compound, Oviposition preference, Lure, Repellent
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