Siberian Moth Research Articles

Syntheses of (Z,E)-5,7-dodecadienol and (E,Z)-10,12-hexadecadienol, lepidoptera pheromone components, via zinc reduction of enyne precursors. test of pheromone efficacy against the Siberian moth.

Efficient syntheses of (Z,E)-5,7-dodecadienol, a pheromone component of the Siberian moth, Dendrolimus superans sibiricus, and (E,Z)-10,12-hexadecadienol, a pheromone component of various Lepidoptera pheromones, were accomplished by cis reduction of the corresponding enynols with activated zinc. The most energetic reagent was zinc galvanized with copper and silver (Zn/Cu/Ag) that achieved rapid and high-yield reduction in methanol-water. The stereoselectivity of semi-hydrogenation was > or =98%. A process whereby zinc dust was continuously activated throughout the reduction with an acid was also satisfactory (95-98% cis). Field evaluation of the 1:1 mixture of (Z,E)-5,7-dodecadienol and (Z,E)-5,7-dodecadienal with the Siberian moth in Russia showed that the rubber septa pretreated with compound and stored at -80 degrees C were as effective as freshly treated septa. Moth responses to septa aged in open air indicated that lure effectiveness declined significantly after 2 weeks of aging. Thus, if rubber septa are used as pheromone dispensers in Siberian moth traps monitoring, they should be replaced biweekly with fresh septa for optimal trap effectiveness.

Carbon Emission by Soils in Forests Damaged by the Siberian Moth

In the southern-taiga low grass–green moss fir forest completely defoliated by the Siberian moth, the rate of soil respiration in the third year after the pest population outbreak was 1.5 times higher than in an undisturbed tree stand. This was explained by a significant increase in the abundance and activity of soil microorganisms in the pest-defoliated forest, which occurred due to the qualitative changes in the litter composition and the increased temperature and moisture in the upper soil layers. The rate of carbon emission from the soil in the defoliated forest was 41.7 kg/ha per day, compared to 28.3 kg/ha per day in the undisturbed fir forest.

USE OF NOAA/AVHRR IMAGERY IN MONITORING SIBERIAN MOTH OUTBREAKS

A large-scale outbreak of the Siberian moth (Dendrolimus sibiricus) in the forests of the Lower Angara valley region (1993-1996) was analyzed on the basis of NOAA/AVHRR imaagery. The applicability of this type of imagery for detecting the foci of damage of tree stands with the discrimination of strong (50-75%) and very strong (>75%) dying and dead trees is demonstrated. The applicability of data from a winter survey was determined by the discovery of damaged tree stands. Summer/winter images were used in demarcating the northern boundary of the focal propagation of the Siberian moth.

A Sex Attractant for the Siberian Moth Dendrolimus superans sibiricus (Lepidoptera: Lasiocampidae)

Field trapping experiments were conducted against the Siberian moth, Dendrolimus superans sibiricus Butler, in Siberia, Russia, using traps baited with a virgin female moth or 100 μg synthetic mixtures of C12 straight chain-length aldehydes, alcohols, and acetates alone or in combinations on rubber septa. Traps baited with a 1:1 blend of aldehydes and alcohols captured many males. The capture rate was similar to the rate of capture seen in traps baited with virgin females. The mixture of aldehydes and alcohols (64% Z,E-5,7-dodecadienal, 10% Z-5-dodecenal, 18% E-7-dodecenal, 8% E-6-dodecenal) and (64% Z,E-5,7-dodecadien-1-ol, 10% Z-5-dodecen-1-ol, 18% E-7-dodecen-1-ol, 8% E-6-dodecen-1-ol) can be used as a sex attractant to monitor endemic Siberian moth populations in Asia, and for surveillance and detection of the moth in countries where the insect might be accidentally introduced.

The influencen of stand state on the occurrence ofDendrolimus superans (Butler) in Daxing’an Mountains

Dendrolimus superans (Butler) occurred in the vast areas of Daxing’an Mountains forest, in Heilongjiang Province, in 1990. Stands damaged byI). Superans seriously, intermediately and lightly show patch shape distribution within damaged area. By ordination analysis and correlation analysis between ordination factors and coordinate axis. It was found that occurrence ofD Superans in different extent is owing to the effect of forest age, composition and exposure. The tended young pure forests grown on the sunward slopes are most seriously damaged and non-tended middle-age mixing stands grown on the sunless slopes are most lightly damaged. Therefore, in order to preventD. superans from seriously damaging larch forests, relatively large crown density (P > 0. 7) should be kept, and broadleaf trees should be also properly preserved.

Quantitative dynamics of larch caterpillar (Dendralimus superans [Buller]) and the biological control

The relationship between pest population and other factors is rather complex within the forest ecosystem. A number of environmental factors, such as extreme climatic conditions, infection of natural enemies, may cause the death of pest insects directly. The effect of these factors reflects basically the situation and cause of death of insects at different stages of entire process of growth and development, so that they may be employed as the basic records of the quantitative dynamic of the population, and are of important value to the study of population quantitative dynamics of pests. Since Morris and Miller (1954) applied the life table technique to study natural population of insects, the insect life table technique has becoming an important means for the study of quantitative dynamics of pest populations. In foreign countries, the study of the life table of forest pest began in 50 year’s already. Moreover, the results of investigation were applied to the productive practice, such as the spruce budworm (Chorisloneura fumiferana Clemens), winter moth (Opperophlera brumata Linnaeus), while in our country, the quantitative dynamics of many forest pests were not investigated. The larch caterpillar is one of the great pest of larch plantation in China. Every year, the outbreak of this pest occur in some places, causing large economic loss. Many studies were performed on the biological and chemical controls, but the investigation on quantitative dynamics of the natural population of larch caterpillar was lacking. Since 1980, we studied the quantitative dynamics of the natural population of larch caterpillar in Shangzhi County, Heilongjiang Province and worked out life tables of two generations.

Causes of outbreak of the larch caterpillar (Dendrolimus superans Butler) in Daxingan Mountain and its control strategy

In 1991, in Daxingan Mountain, an outbreak of larch caterpillar (Dendrolimus superans Butler) happened on large areas of more than one million hectares, where stands of larch were seriously damaged because needles on the trees were almost eaten up by the pest, causing enormous economic losses. Analysis of data collected indicated that the main cause of the outbreak of larch caterpillar on large areas was that, after thirty years of exploitation, mature and overmature forests decreased rapidly, middle-aged and young forests incresed in large amount, significant changes occurred in individual ecological conditions of stands, especially those tended, with decreasing canopy density and better light condition in the forest, and all these were adventageous to the outbreak of the pest. In addition, in recent years, the climatic condition in Daxingan Mountain changed significantly. The yearly average temperature raised gradually and the soil surface temperature in April and October increased year by year, which were advantageous to the outbreak of larch caterpillars. In short, the significant changes in the ecological conditions in Daxingan Mountain provided suitable conditions for the outbreak of the larch caberpillar, and after several years of increase in population number, the larch caterpillar outbroke into a serious disaster on vast areas. In the paper, composite control strategy was also discussed.

A preliminary study on the nuclear polyhedrosis virus of larch casebearer

The nucleopolyhedrosis virus(NPV) of larch casebearer (Dendrolimus superans) is in quadrangle or irregular form. It’s diameter is ranged from 1.21 μm to 2.33 μm. There is one or many virions in each envelope. The size of the virion is about 29.1-60.5nm × 244.2-325.6nm.

Natural adjustment of population density of Larch casebearer (Coleophora dahurica)

Population increase of Larch casebcarer (C. dahurica) were controlled by comprehensive factors. Spring wind caused 27% of larvae on crown to fall down. Early and late frosts, larch caterpillar, sawfly and needle cast of larch could reduce the food quality and quantity of larch casebcarer and had indirect effects on population density. Birds, ants and spites were the main predators ofC. dahurica. The parasite complex comprisedPtermalidae, Eulophidae, Ichneumonidae andBraconidae. “Self-adjustment”, of population caused by “self-population density”, only runs effectively at a high larval density.

Pest control in natural and man-made forests in northern Japan

Natural enemies and life-history traits were studied for the control of Choristoneura jezoensis Yasuda et Suzuki, Dendrolimus superans (Butler) and Lymantria dispar (L.) in Hokkaido, northern Japan. Outbreaks of the todo-fir budworm, C. jezoensis, occurred during 1965–1975 in plantations of Abies sachalinensis Masters. The population in natural forests, however, remained at low levels during this period. Natural mixed forests were preferred to man-made forests for controlling pests. I present control methods utilizing life-history traits of the pests. The hemlock caterpillar, D. superans, overwinters in the soil in its larval stage. To control the pest, every tree trunk was banded with vinyl tape to impede larvae crawling up to the canopy. Another method is for the gypsy moth, L. dispar. In Hokkaido the female oviposit below the branch. Higher egg-masses suffered greater predation by birds. This predation was increased by pruning of the lower branches.

Electron microscope investigation of granulosis viruses of Dendrolimus sibiricus and Agrotis segetum

The fine structure of virus particles isolated from capsules of the Siberian silkworm, Dendrolimus sibiricus, and the cutworm, Agrolis segetum, was studied by use of the electron microscope. It was shown that alkaline treatment of virus suspensions destroys virus particles and liberates DNA strands, with intimate and developmental membranes preserved. The fine structure of virus particles of capsules and polyhedra and DNA packing in virus particles are discussed.

Studies on the Pine moth (Dendrolimus superans BUTLER) occurred at Tsubetsu in Hokkaido

Studies on the Pine moth (Dendrolimus superans BUTLER) occurred at Tsubetsu in Hokkaido