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(B) Investigation method for pathogenic spore dispersal period
In a fixed standard area, five strains were set up by the 5-point sampling method. From June to July, slides were set on the litter layer (leaf disease) or the canopy of specimens (blight disease) in the sample plant. Apply Vaseline on the film, replace the glass slide every two days, bring it back to the room, observe the two strips in the middle of each slide with a 400x microscope, count the number of spores with a counter, and measure with a micrometer The area of ​​the field of view is calculated and the number of spores captured per square centimeter is calculated. When the beginning of the discovery of spores is the beginning period, the number of spores begins to increase, it is the peak period, when the number of spores reaches the maximum, it is the peak period. After a large number of spores are reduced, it is the end of the period, and when the spores cannot be captured, it is the end stage.
(III) Prediction Methods
1. Forecast of occurrence period
According to the actual survey of the pathogenic spores' scattering period, a practical investigation method was adopted to issue appropriate prevention and control forecasts when spore scattering reached a peak. Such as larch early defoliation, when the number of spores captured per square centimeter reaches more than 100 can be issued when appropriate control forecast.
2, the amount of forecasting statistics method and experimental methods
(1) Statistical method: It uses statistical principles to find out the internal relationship between environmental factors and disease occurrence from historical data of disease occurrence, and then predicts the occurrence of diseases based on current environmental factors, such as:
1 Larch early deciduous disease prediction
Y=68.31-1.68X1-0.5638X2+0.36X3
In the formula: Y--predicts the current year's disease index; X1--the average temperature in April and May of that year; X2--the average relative humidity in June and July of that year; X3-the precipitation in June and July of that year
2Litter blight of Larch When the average temperature, relative humidity, and precipitation in April and May are not lower than the average local year, the average temperature in June and July will be above 17°C, the relative humidity will be above 80%, and the precipitation Above 200mm, it is predicted that the onset will be heavy; when the above four meteorological factors in April and May are not lower than the general years, the relative humidity will be between 70 and 80% in June and July, and the incidence in the year is expected to be moderate; when in April and May The above three meteorological factors are lower than the normal years, and the relative humidity in June and July will be lower than 70%. The forecast is slightly mild in that year.
(2) Experimental method: It is a method of predicting disease through the use of methods of ecology, biology, and physiology, such as forecasting nurseries, systematic investigations, spore capture, and artificial cultivation.
Section II Major Pests of Larix principis-rupprechtii
In the animal kingdom, insects harm trees and seedlings most seriously. It is also the largest and largest group in the animal kingdom. There are more than 1 million species recorded in the world. Most of them are the roots, stems, leaves, flowers, fruits and seeds of plants. The vast majority of insects are pests. Forest pests have a great impact on the growth and development of forests. L. caterpillars and L. gmelinii reduce the growth of forest trees when the damage is severe. In recent years, forest trees have stopped growing or died.
Prevention and control of Larix principis-rupprechtii pests should be guided by the principle of “prevention first, comprehensive prevention and controlâ€, proceeding from the overall concept of biology and the environment, and be based on the principles of safety, efficiency, economy, and simplicity. Use forestry technology, chemistry, biology, physics, and other effective ecological methods to control pests to a level that is less harmful, in order to achieve the goal of ensuring the health of humans and animals and increasing forestry productivity.
The main pests that damage Larix principis-rupprechtii in the woods of the Mengzi Forest Management Bureau include larch caterpillars, larch tussock moths, larch borer leaf flat bees, northern China larch sheath worms, gypsy moths, and larch cone flies.
First, the main leaf pest
(i) Dendrolimus superans (Butler)
1. Taxonomic status Lepidoptera Bombycoidea Bombycidae Lasiocampidae
2, distribution
Domestic Heilongjiang, Jilin, Liaoning, Inner Mongolia, Hebei, Xinjiang and other provinces; foreign countries such as the Soviet Union, North Korea, Japan, and Mongolia.
3, identification characteristics
(1) Adults: Female adults are 28 to 45 mm in length, wingspan 70 to 110 mm, and antennae are dentate; males are 24 to 37 mm in length, wings are 55 to 76 mm, and antennae are feathery. Body color and spot change are larger, with wider fore wings, outer edge wavy, lesser inclination, dark brown inner and outer horizontal lines, jagged outer transverse lines, and 8 dark spots on sub-peripheral lines. It is in a 3-character shape. The last two spots are nearly parallel to the outer edge when they are in line. The middle class has a clear day shift, and there are light-colored markings in the middle of the hind wings.
(2) Egg: oval. About 1.8mm long, about 1.6mm wide, pale green at the time of first production, then turned yellow, red to dark red, arranged in disorder.
(3) Larvae: The larvae of mature larvae are 68-72mm in length, and their body color changes greatly. They are smoke black, grayish black and grayish brown. The head is brownish yellow, dark brown in the frontal area and frontal area, and a triangular dark brown spot in the center of the frontal area. There is a pair of blue and black poison hairs on the back and back of the chest. The back of the abdomen is black, and the lateral hairs are silver-white, and the markings are sometimes inconspicuous. The back of the eighth abdominal section has a pair of dark blue hairs. The breasts and abdomen have long, pointed tips, mostly spindle-shaped, with no dentate protuberances at the tip.
(4) Cockroaches: body length 40 ~ 60mm, yellowish brown or dark brown, dense golden short hair. Cockroaches gray or gray-brown, many blue and black larvae are attached to the surface.
4, occurrence characteristics
2 years 1 or 1 year. In the 1st and 1st generations of the Mengzi Forest Management Bureau in Hebei Province, the larvae of 3 to 4 instars live through winter, the daily average temperature starts to fall below 9°C and the winter begins, and the daily average temperature stabilizes at 9°C, and the wintering larvae reach 5 in mid-April. In the beginning of the month, the upper tree began to move and the wintering mortality rate was 35%. Overwintering larvae feed on buds first, and then leave the whole leaf after leafing. When feeding, the chest foot clings to the pine needle and starts to feed from the tip of the needle. When it is disturbed, it falls to the ground and does not move. In late June, pods and phlegm began to phlegm. In early July, it was the peak of phlegm; in late July, it was the end of phlegm; adults began eclosion in late July, and in late July and early August, they were eutrophic, and in mid-August they were eclosion. At the end; feathering is more concentrated, adults have a strong phototaxis, usually at dusk and sunny evenings. After mating, they fly to the lush pine trees and spawn on the branches and needles in the middle and lower part of the canopy. In early July, the eggs began to appear. In August and mid-October, the spawning period was high. In the middle and late August, it was the end of spawning. The eggs became lumpy and arranged irregularly. Each female can lay between 128 and 515 eggs. Adults live 4 to 15 days. After 12 to 15 days of egg hatching, the newly hatched larvae are clustered on top of the shoots, and when they are disturbed, they droop and droop to other branches. Gradually scattered after 2 years of feeding, by the alarm no longer droop drooping, but directly fall to the ground. Larvae are 7 to 9 years old.
Larch caterpillars occur in leeward sunny, sparse and dry larch pure forest. After more than 2 to 3 years of continuous drought, the larvae were harmed. After the pupa, due to the increase of natural enemies, the foodstuffs were in short supply, and the density of the larvae decreased. It was even difficult to see live worms. The unfavorable climate for this worm is the cold and wet weather with heavy rainfall and the torrential rain and low temperature after the larvae emerge out of the larvae. Such climate has obvious inhibitory effects on its occurrence.
5, control methods
Larch pine caterpillar is a devastating pest that is easy to occur and difficult to suppress. When formulating prevention and control measures, we must firmly grasp every weak link in the living environment of pine caterpillars, and comprehensively apply various prevention and control methods. Control in time makes it not a disaster.
(1) Forestry Measures Forestry measures are the fundamental measures to increase the integrated pest resistance effect of pine forest ecosystem, exert the potential of self-control, and adjust the dynamics of pine caterpillars to avoid insect pests.
Reasonable afforestation: to create a mixed forest: As a result of its complex forest, mixed forests often have more natural enemies, and the microclimate is also relatively unfavorable to the growth and development of pine caterpillars, and it has certain barrier effects on the food of pine caterpillars. This is usually evaluated. The reason for the unfavorable growth of the pine caterpillar population in the mixed forest.
Reasonable dense planting: Forest land is too sparse, airy and transparent, which is often conducive to the growth and development of pine caterpillars. Appropriate dense planting is not only conducive to the growth and development of larch, but also a highly closed forest environment has a greater inhibition on the population of pine caterpillars.
2 Improve forest management technology
Closing the mountains to cultivate forests: The management of forest cover damaged by the destruction of forest land and poor growth of larch is very beneficial to improving the forest condition, restoring soil strength and improving forest growth. The complex forest phase also exerts obvious control over the dramatic increase of the population of larch caterpillars. effect.
Timely tending and transforming the sub-forests: timely nurturing is a necessary measure to promote the healthy growth of forest trees and transform the environment of larch forests.
(2) Artificial control
1 To kill overwintering larvae: The severe occurrence of the larvae occurs between late November and late March of the following year. In the overwintering sites of pine caterpillars, such as stones, bark joints, weeds, artificial capture and then burned or contacted with chemical pesticides. This method can significantly reduce the population density.
2 Picking pods: After larvae have been pupaed, they can be cut off or hooked off with scissors or wire hooks.
3 Picking eggs: The eggs of pine caterpillars are easy to find. Eggs are manually collected and disposed of in a centralized manner to reduce the density of insects in the second year.
(3) Chemical control: Spraying 4.5% high efficiency cypermethrin emulsifiable concentrate with No. 0 diesel at a ratio of 1:14 with a smoke machine to prevent and treat 4 to 5 years old pine caterpillar larvae. The control effect can reach over 95%. When controlling pine caterpillars of young larch, they can be sprayed with a Knife-type motorized sprayer and sprayed with a spray of 4.5% high efficiency cypermethrin 800 to 1500 times; and a stretcher-type “165 workers and peasants 36†high pressure sprayer can be used to prevent and control the forest. It can reach more than 95%, but its prevention and control costs are about 50% higher than those with a smoke machine. You can also use the poison pen to draw a ring in the trunk.
(4) Biological control measures
1 Protection and use of natural enemies: Parasitic insects: Trichogramma controls pine caterpillars, hangs eggs in the forest, hangs eggs on the shady side of the trunk and rises up against the wind. Put the bee on the bee's ability to move (radius 7 to 10 meters) 6 to 8 cards per acre can be put every day bee time can be 15:00 to 16:00 points, strong winds, heavy rain weather should not bee.
2 Use Beauveria bassiana to control pine caterpillars, which can be sprayed or sprayed. The Beauveria bassiana is sprayed in early May, with a daily temperature of 18°C ​​and a humidity of 70%. It can be carried out on a cloudy day, after a rain or in the morning with dew. Temperature and humidity can not meet the requirements of bacteria breeding and development, the control effect is not good.
(5) Pollution-free prevention and control: Using a smoke machine to control 4th to 5th instar larvae: Spraying 1.2% bitter/fumarocyanine oil and 0# diesel oil at a ratio of 1:7, the control effect can reach over 92%; Efficacy of the combination of phenytoxil and No. 0 diesel in the ratio of 1:5, the control effect can reach over 90%; and the spray of 0.6% avermectin and No. 0 diesel in a ratio of 1:5. The control effect reached more than 92%.
(ii) Erectis ankeraria Staudinger
1. Taxonomic status Lepidopterac Geometridae
2. Distribution in China: Hebei, Inner Mongolia, Shaanxi, and abroad: Hungary. This worm is an important pest of larch. In the 1980s, the area of ​​this insect was more than 400,000 mu in Weichang County, Hebei Province, and the maximum number of insects per plant was 20,000. The impact on high growth was extremely significant in 2 to 4 years after the victimization, and the diameter growth and volume growth were achieved when the loss rate was 100%. The effects are extremely significant.
3, identification characteristics
(1) Adults: female adult spindle-shaped, body length 12 ~ 16mm, no wings, only scaly protrusions. The head is dark brown with a white patch of white scales on the top of the head. The antennae, compound eyes are black, and antennae are filiform. The body is grey and white, with irregular dark spots. There are 1 pair of dark spots on the back of each section of the chest. The first section of the abdomen has 1 pair of dark spots. The rest of the sections are covered with dark spots from the midline and both sides of the dorsal midline. There is one side black line from the head and the compound eye. Slim, black, each section has 1 to 2 white ring spots. Male adults have a body length of 14-17mm and a wingspan of 38-42mm. The body is tan-brown with a pale yellow head and compound eyes are black. The tentacles are tentacles, tentacles are pale yellow, and caries are yellow-brown. The chest is densely covered with long-scaled hairs, yellowish-winged wings, irregularly brown spots on the front wings, and yellowish lines. The front wings are dark brown and have a large curvature. There is a dot on the middle chamber. The horizontal lines and round spots of the hind wings are more ambiguous than the front wings.
(2) Eggs: oval, 0.6-0.9mm, initially contaminated white, gradient milky white.
(3) Larvae: body length 27 ~ 33mm, yellow-green, brown head, rough shell, reddish brown pattern, upper lip light brown, lack of cut edge darker. Yellow and white tentacles, inner measurement with a dark brown dot. Body wrinkles, back, belly with 10 intermittent black lines. The valve line and the ventral midline are yellowish-green, with long oval pores and black edges.
(4) Cockroaches: 12-18 mm in length. The upper half of each segment has a round engraved dot, the lower half is smooth, the distal segment is brownish black, and it protrudes to the back. The thorns at the end of the thorns are juxtaposed with 2 thorns and extend obliquely toward the ventral surface. Oval shape, length 15 ~ 22mm.
4, the occurrence of characteristics in the forest area of ​​Mengzi Forest Management Bureau a year, wintering eggs. In early May, when the average temperature reached above 9°C, hatching began. At this time, the larch buds had opened and the leaves were tender and about 3mm long. The newly hatched larvae ate in the vicinity of the newly-opened bud package, and the food intake increased after 3rd instar. Speed ​​up, until the middle of June, the larvae will stop eating when they are approaching maturity. When the larvae are seriously damaged, they can eat up all the needles and have the characteristics of endangering the disaster. The larvae were 5 instars. In late June, the mature larvae drooped or fell directly to the ground, and then they crawled around to find a place to enter the earth. Generally distributed vertically in the soil from 3 to 5 cm above the ground surface, and the individual larvae in the litter layer. The larvae under the tree are relatively tidy, generally within 3 to 5 days. The flood season is longer, from the end of June to the end of September, about 80 days. In late September, quails begin to emerge. The eclosion time is mostly in the morning. The females are good at crawling and climb up after emergence. Males have a dead-dead habit and are in touch. At night, the eggs are prolific in the open cones of fruit and a few are produced in the bark joints. The greater the degree of canopy closure, the heavier the damage, the more the canopy closure of 0.85 or more, can all be harmed; artificial pure forest, hawthorn, and forest victims are heavy.
5, control methods
(1) Forest management measures: Tendering should be conducted in time, reasonable cutting should be conducted, and excessive logging should be prohibited.
(2) Manual control: The larvae have drooping drooping and accustomed grounds, and can kill the larvae after they fall.
(3) Biological control: protect and utilize natural enemies. From 1983 to 1984, the nuclear polyhedra virus of L. gmelinii was widely distributed in the forest of Larix principis-rupprechtii in the forest area of ​​Mengfu. The incidence rate of larvae was more than 96%, which greatly reduced the incidence of the larvae in the following year.
(4) Chemical control
1 Liquid spray: It is required to work in the weather without rain or wind. With the use of 4.5% high efficiency cypermethrin EC 1000-2000 times, the canopy cover spray can prevent 2 to 3 instar larvae, and the control effect (after 2 days) can reach more than 95%. Advantages: Good control effect, especially for older larvae; Disadvantages: Large investment in labor.
2 Smog prevention and control is applicable to stands with a canopy closure of more than 0.6 and away from water sources. Using a fog machine to prevent and control the application of 4.5% high efficiency cypermethrin EC with a 0:1 diesel ratio of 1:16, the control effect (after 5 days) can reach over 94%.
6. Non-pollution prevention and control using a smoke machine to control 2 to 4 instar larvae: Spraying 1.2% bitter/cow EC and 0# diesel at a ratio of 1:8, the control effect can reach over 93%; 3% of discharge is high Efficacy of the combination of phenytoxil and No. 0 diesel in the ratio of 1:5, the control effect can reach more than 91%; spray of 0.6% avermectin and No. 0 diesel at a ratio of 1:7. The control effect can reach more than 92%.
(iii) Cephalcia lariphila (Wachtl)
1. Taxonomic status Hymenoptera Megalodonoidea
Pamphiliidae Cephalcia Panzer
2. Distribution in China: Heilongjiang (Hailin), Shanxi (Guanshan Forest District), Hebei (Weichang County, Fengyi County), and foreign countries: Finland, Netherlands, Belgium, United Kingdom, Germany, Switzerland, Italy, Czechoslovakia, Russia ( Irkutsk region).
3, identification characteristics
(1) Adults: Females are 10 to 12 mm in length. Black head; most of the lip base front and center, tentacles side area and the rear square pattern, the next two round spots in the middle unilateral eye, the long side of the side seam, the cheek and the posterior region of the posterior eye, and extending The fine lines connected to the square pattern on the side of the antenna are yellow-white. Most of the antennal shank segment, the back of the stem, black; whip red-brown, its darker end. Chest black; front and back of the chest plate most of the back, in the chest after the scutum posterior, mid-thorax scutellum rear near the square pattern, the middle chest scutellum on the pattern, fins are yellow-white. Translucent wings, microstrip yellowish, apex and outer edge slightly smokey brown; wing wings and wing veins dark brown; wing tail has a light brownish-brown transverse band leading to the trailing edge of the wings. The festival is full of yellow and the rest of the festival is black. The abdomen is black; both sides of the back plate, the rear edge of the second to the eighth back plate, and the rear edge of the web are all yellow. The lip base is flat; the frontal ridge is not prominent; the middle nest is shallow; the side seam, crown seam, and transverse seam are obvious; The engraved abdomen is finely detailed and has a fine, horizontal wrinkle-like appearance. Antennae 23 knots. The scorpion body length is 8-9mm. The head is black; along the cheeks and the posterior border of the eye, the posterior edge of the striated, most of the antennae side area, the base of the lip base and the center are yellow; the antennal shank section is black on the back, and the rest is reddish-brown and black on the tip. Chest black, both ends of the thoracodorsal plate and the fin base yellow-white; the first half of the leg section is yellow. The abdomen is black; both sides of the back panel and the holder are yellow. The engraved points on the top of the head and the back of the eye are denser than those of the females. Antennas 23 to 25 knots.
(2) Eggs: Long oval, slightly curved, 1.8 ~ 2mm long, the same color as the coniferous leaves at the time of first birth, silvery gray at the time of rapid hatching.
(3) Larvae: Mature larvae are 15 to 20 mm long, gray-brown. Head cover, tentacles, dark brown around the valve; tail and chest legs dark brown, later become grass green or green.
(4) 蛹: mouthparts, compound eyes, tentacles light green, tentacles up to the fifth quarter of the abdomen.
4, occurrence characteristics
(1) Life history: One generation occurred in the forest area of ​​the Mengzi Forest Management Bureau in one year, and wintering in the soil was pre-arrived in the soil. A few of the pre-cockroaches had diapause, and they could emerge after more than one year. Overwintering precooking in the middle of April the next year in the soil Huayu, in late April for the prosperous, in early May for the end of the month; in early May the eel began to feudal, mid-May for the prosperous, late May for the end of the last; In mid-May, the adults began to lay eggs. In late May, it is the prosperous period. In early June, it is the end of the silla. In early June, the eggs begin to hatch. In mid-June, it is the prosperous period. In late June, it is the grand dynasty. From mid-June to early July, For the hazard period, the mature larvae started to do the earthwork under the tree in late June and become pre-wintering. (See Table: 7-1)
Table 7-1 Larval Age Grade and Food Consumption
Age level
Head shell width mm
Body length mm
Duration (days)
Feed intake (clusters)
Feces mm
Fecal visibility
1
0.5 to 0.7
2 to 4
4
Very few, no missing leaves
Did not find
no
2
0.7～0.8
4-8
5
Outer half cluster needles
0.3×1.0
There are
3
0.8 to 1.0
8 to 12
5
2 to 3 clusters
0.7×1.5
Leaves clusters and visible on the ground
4
1.0 to 1.2
12 to 15
3
4 to 5 clusters
0.9×1.8
Obviously visible
5
1.2 to 1.5
15 to 20
4-8
5 to 7 clusters
1.0×2.0
Obviously visible
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