Using Luseweilei insecticide to control Dendrolimus superans T.

Luseweilei is an easily-bursted microcapsule insecticide. A test of effectiveness of the insecticide to control the larvae of Dendrolimus superans T. was carried out in larch forest in Baoan Forest Farm of Nehe City, Heilongjiang Province, in April 2001. The solutions of different concentrations (1:150, 1:250, 1:350, and 1:450 Luseweilei : water) were sprayed on the larch trunk before the overwintering larvae climbing on trees and the spraying lengths (height) designed were 1.0, 2.5, and 3.5 m high from ground. The control result showed that spraying 150-, 250-, and 350-fold solutions of the insecticide all produced a good control result, with a mortality rate of 97%, but the 450-fold solution only produced 70% mortality. It is concluded that this insecticide can be used as a kind of good insecticide to control the overwintering larvae of D. superans in spring. Spraying 350-fold solution of easy-burst microcapsule insecticide and one meter spraying length are recommended for the future application..

Population Characteristics of Dendrolims Superans in Daxing'an Mountains

Dendrolims superans produced one generation every two years Large larvae and small larvae exist at the sametime. lt broke out in Daxiang an Mountains in 1990. and seriously destroyed growth of Larix gmelum Rupr In order to control D Superans.the population properties of D.superans were stedied from 1991 to 1992 including sex ratio.age distribution. pattern etc.. The sex ratio of D. superans population is The larvae age distrihution indicates that larvaeover 5 instar is less than younger larvae under 4 instar in Yongqing forest farm- but the younger larvae under 4 instar is morethan larvae over 5 instar in Hanjiayuanzi Forest Farm. The population of D. superans in Yongqing Farm has heen declining.and incrcasing in Hanjiayuanzi. Pupae and eggs are mainly distributed in middle and lower crowns layer of trees. respec-tively account for 66% and 59.5%, of total individuals. The pupae in higher cown layer is lightly regular distrihution. andclumping distribution middle and lower crowns layer of trees. The eggs in higher crown is light clumpin1g distribution. andrandom in middle and low crown of tree.

Study on Cytoplasmic polyhedrosis virus on Dendrolimus superans

A strain of Cytoplasmic polyhedrosis virus (CPV) was separated from the infected larva during the research of integrated pest management of Dendrolimus superans. The morphology bioassay histopathology andfield-test for this CPV were studied. The size of CPV is 0.16 μm ×1. 57μm and the virion is 16.0 nm × 58.1 nm.The Lc50 to the 3rd and 5th instar larva of Dendrolimus superans were 2.81 × 104 PlB/mL and 7. 17 ×104 PIB/mLrespectively. The polyhedrosis were formed after midgut of larva were infected for 72 h. A large amount of polyhedrosis was formed after 144 h. The mortality was more than 82% and average mortality was 84.62% when using1 .17× 10s PIB/mL virus suspension to control the pest in field test.

New cell line establishment of a cell line from embryos of Dendrolimus superans

A new cell line was established from 5-day-old embryonated eggs of Dendrolimus superans and has been designated NEAU-Ds-950821 .The cell line consists of mixture of cell types, including majority of spherical shaped cells and a few of spindle shaped cells. The cell line has a population of doubling time of 52.6 h. Chromosome analysis levealed typical lepidopteran chromosomes. lsozyme characterization of Esterase showed the patterns were different from other three cell lines (Ms-927311. Xc-920730, and SF21AE). Virus infectivity tests revealed the cell linc can support D. superans cytoplasmic polyhedrosis virus.

The effect of Dendrolimus superans breakout on growth of trees

The effect ofDendrolimus superans on growth of trees was investigated after the breakout in Shibazhan forest area in 1990. Stem analysis was conducted for determining the tree increment loss. The result showed that the current annual increment for extreme heavily damaged, heavily damaged, moderately damaged and lightly damaged stands is 14%, 39.8%, 64% and 82% of that of the control forest respectively.

THE INFLUENCEN OF STAND STATE ON THE OCCURRENCE OF DENDROLIMUS 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 by D.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 of D. 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 prevent D.superans from seriously damaging larch forests. relatively large crown density (P>0. 7) should be kept,and broadleaftrees should be also properly preserved.

An Indoor Proliferation Method of DpCPV with Dendrolimus superans

The study explored a DpCPV proliferation method with Dendrolimus superans.When large amounts of DpCPV were obtained,they could be used to prevent and control the 2nd-4th instar larvae of D.superans.

Invasive sequence and ecological niche of main insect borers of Larix gmelinii forest in Aershan, Inner Mongolia

After the outbreak of Dendrolimus superans Buter in 2002, many insect borers quickly invaded larch （Larix gmelinii Rupr.） forests in the Aershan of Inner Mongolia. Methods involved included setting sample plots, collecting adults in iron traps and measuring areas of galleries to study the invasive sequence, their ecological niche and the extent of the different effects by the main insect borers to their hosts. The results showed that the damage of D. superans weakened L. gmelinii, first Ips subelongatus Motschulsky invaded, followed by Acanthocinus carinulatus Gebler, Monochamus urussovi Fisher and M. sutor L. After the outbreak of D. superans, the average density of longhorn beetles per L. gmelinii tree increased. The ecological niche of Ips subelongatus stretches almost from the base to the top of the trunk. The number of insects in older stands of L. gmelinii is larger than those in middle aged stands. They do not damage healthy trees of L. gmelinii. The ecological niche of A. carinulatus is higher in dead L. gmelinii trees than in weak ones. The degree of damage is directly proportional with age and depth of bark. M. urussovi mainly damages trunks below 4 m in weak trees; in dead trees they can do damage up to 6 m in height. M. sutor mainly damages trunks below 5 m in weak L. gmelinii trees; in dead trees they cause damage up to 7 m. Again, the degree of damage is directly proportional with age. None of the three species of longhorn beetles damage healthy L. gmelinii and younger trees. Among the main insect borers, the degree of damage caused by I. subelongatus is more serious than that of other insects.

Development, manufacture and application of Beta-Cypermethrin aqueous capsule suspension

The optimal formula of Beta-Cypermethrin aqueous capsule suspension was screened out through the experiment, preparation and manufacture of basic formulas, which has no sedimentation, suspended drops of oil, peels and agglomerating and the diameter of capsule is in range of 10-30 靘, conformed to the technical requirement. The aftereffect of the 3.3% Beta-Cypermethrin aqueous capsule suspension which was manufactured according to the optimal formula was up more than 25 days. The experiments on controlling the larvae of Dendrolinmus superans Butler and the adults of Xylotrechus rusticus L were carried out with different concentrations of this chemical. The death rate reached 80% when 250 times solution of the chemical was sprayed on stem to control the larvae of D. superans. For control of the adults of X. rusticus, 200, 400 and 600 times solution of the chemical were applied and their control effects (death rate) reached 85.23%, 74.21% and 66.59% respec-tively. Two kinds of solution (200 times and 300 times) of the chemical were used to control the larvae of D. superans in large area, and the control effect for both concentrations was over 90%.

Identification of sex phero-mones of four economically important species in genus Dendrolimus

The female-produced sex pheromone of Den-drolimus superans was identified by gas chromatography (GC), coupled GC-mass spectrometry (GC-MS), electroan-tennographic (EAG) studies and field tests as a blend of (Z,E)-5,7-dodecadienal (Z5,E7-12:Ald) and (Z,E)-5,7-dodeca-dien-1-ol (Z5,E7-12:OH). In D. kikuchii, (Z,E)-5,7-dodeca-dien-1-yl acetate (Z5,E7-12:OAc) and Z5,E7-12:OH were found by GC and GC-MS analyses. However, in EAG studies male antennae were more sensitive to Z5,E7-12:OAc and (Z,E)-5,7-dodecadien-l-yl propionate (Z5,E7-12:OPr) than Z5,E7-12:OH. For D. spectabilis, Z5,E7-12:OH had been previously reported as the sex pheromone. However, in our studies, traps baited with Z5,E7-12:OH, Z5,E7-12:OAc and Z5,E7-12:OPr in a ratio of 1:1:1 caught three times more males than those baited with Z5,E7-12:OH alone. Relatively strong EAG responses were elicited from male antennae by Z5,E7-12:OH, Z5,E7-12:OAc and Z5,E7-12:OPr, but in addition to Z5,E7-12:OH, only very small amounts of Z5,E7-12:OAc was found in