Table 7-5 Insect investigation ledger
Forest work area, small place name
Insect species class / small class size class area aspect slope origin
Linlin forest composition distribution number of acres of canopy closure
Average High Average Breast Diameter Branch Count Crown Height Crown Height
Crown damage ratio represents area standard area
Grass cover and main species
Plant No.
meter
Number of live insects (larvae, fleas, pre-spawns, eggs)
Number of dead insects
Plant No.
meter
Number of live insects (larvae, fleas, pre-spawns, eggs)
Number of dead insects
1
11
2
12
3
13
4
14
5
15
6
16
7
17
8
18
9
19
10
20
total
Average insect density (bars, heads, grains/strains) Infestation density (bars/strains)
Insect strain rate of natural enemies
Suggested preventive measures
Surveyor: Survey Date:
(4) Survey Method
Scope of occurrence (area) survey: Based on the overall investigation, it is determined by reference to the original sub-class area estimation.
Stand survey: According to the contents of the field survey of insect pests (Table 7-5), refer to the original class 2 investigation class card, and fill in the forest outline by visual inspection.
Existing insect population density survey:
1 Set the standard place: In the small class of insect pests (adjacent and same type, several small classes with the same insect species can be combined into one pest class), through the inspection, choose a representative plot to set up standard plots, every 400~ A piece of 1,000 mu is set. There must be at least 120 or more trees in the standard ground. The shape of the standard ground is a special rectangular shape (length is 2 times the width), and the method of investigating the single diagonal line is adopted. In order to reduce the workload, a representative survey line (that is, a single diagonal line of a standard rectangular land) can be directly set without actually setting up a standard site. The specific operation steps are: a. Determine the number of blocks and area of ​​the standard land based on the area of ​​the small class of insect pests and the density of the trees of the stand. b. According to the determined standard area, use the Pythagorean Theorem to calculate each block that should be investigated. Single diagonal length of a special rectangular standard ground. Suppose: The special diagonal single diagonal is c, and the area is s, then c=√10s/2.
2 Selection of sampling tree: Based on the calculated diagonal length of the investigation sheet and the determined number of investigated samples, calculate the sample spacing, and then select the sampling tree (the closest one from the survey site) on the survey line.
3 Survey population densities: Depending on the location of the insects, tree and tree surveys were conducted.
a. Tree survey (applicable to this section of the North China larch sheath moth and gypsy moth): Survey of the larch sheath moth: In the selected survey tree, using high branches and scissors and other tools in the tree crown two layers (such as If the height of the branches is more than 5 meters, the middle layer and yin and yang are desirable, and one sample branch is alternately rotated on each tree. The main branch of the sample branches is more than 50 centimeters long, and then an extension branch of more than 100 centimeters is cut on it. Include non-year-old shoots, measure the actual length of the sampled branches, check the number of healthy insects, and record the results in the field of insect pest investigation (Table 7-5), and indicate the length of the extension branch, the sample-like site, the internal industry To calculate the average number of insects per 100 cm of extensions on each tree, that is, the population density; for the gypsy moth investigation: due to spawning of the gypsy moth, the egg position is fixed and easy to find, plus the egg's long duration 8 to 9 months. Therefore, a visual inspection method can be used. Visually measure the number of egg masses on the selected survey tree and investigate all egg masses on all other objects on the ground within the vertical projection of the tree crown. Add the egg masses of the entire tree and then survey the average. The egg density of the whole tree can be calculated from the number of eggs per egg mass and recorded in the insect investigation field (Table 7-5).
b. Under the tree survey (applicable to this section of the larvae of the caterpillar, larch, moth, larch, and larch cone flies): For the selected survey tree, follow the northeast and southwest directions in each tree. Take a 1/8 canopy vertical projected fan shape (radius × 2π/8 = fan-like arc length) on the lower surface to collect all litter, pre-cockroaches, and larvae in the litter layer and the soil surface. , Counting the number multiplied by 8 is the density of predock, pre-cockroach and larvae of single tree, and it is recorded in the field of insect pest investigation (Table 7-5).
c. Obstruction collection surveys can also be used for the larch caterpillars. Before the wintering of the worm-eaten tree, a plastic bowl was wrapped around the height of about one meter high of the trunk of the selected sample tree and the number of larvae was measured. For small trees, the number of larvae on the tree can also be directly counted; for larger trees, tree sampling survey methods can also be used.
Small class average insect population density (bar, head, grain)/strain = Sum of various tree species / Total number of sample trees.
2. Measure the occurrence of leap year
(1) Density of larvae in larvae: According to the density of worm populations in autumn, the coefficients are calculated according to Table 7-6.
(2) Degree of damage: According to the calculated density of larvae and larvae, determine the statistics according to Table 7-7.
(3) Rate of insects: The percentage of insect-like trees and the total number of sample trees were counted.
(4) Occurrence area: counted from the starting point of light statistics. Two or more pests occurred in the same small class, and one of the major areas was calculated and an additional note was added.
3. Determine the area for prevention and control of leap year
The area of ​​moderate or higher degree of damage was measured, which was the area of ​​prevention and control for the following year.
(B) Spring Survey
1, time requirements: from late March to mid-April.
2. Scope of investigation: According to the results of the autumn survey report of the previous year, the survey focused on the prevention and control of small classes.
3, survey, forecasting method: the same autumn tune forecasting method.
4. Determine the area to be prevented: The area surveyed and reported that the degree of harm is still moderate and above is the area to be prevented.
(c) Anti-prediction report
1. The monitoring personnel at each monitoring site shall inspect the pest situation in the responsible area every day during the occurrence and damage season of larch insects, and focus on monitoring the planned control plots, and report the situation to the monitoring sites (forest farms) once a day ( Including: place of occurrence, area of ​​occurrence, insect species, density of insect population, activity status, etc.).
2. Based on the monitoring situation reported by the monitoring points, the forest farm will use the time period forecasting method to make short-term forecasts so that preventive measures can be taken in time.
The following are the durations of the larvae to the defense of the major pests before they are monitored, and they can be used when determining the time of prevention and control.
(1) Larix principis-rupprechtii: In the beginning of April, the overwintering larvae should be prevented and treated only after about 23 days.
(2) Larix principis-rupprechtii: It should be controlled about 15 days after hatching larvae in early May.
(3) Larix principis-rupprechtii: In the middle of May, adult insects were seen in the middle of May, and they should be controlled about 13 days after hatching larvae in early June.
(4) Larix principis-rupprechtii: In late April, sap flows, and the larvae begin to move when buds sprout. The first 7 to 9 days after the emergence of the larvae is the time for the larvae to make a new sheath. The naked body is the best period for chemical control.
(5) Gypsy moth: It should be controlled about 14 days after hatching larvae in late April.
(6) Larch cone flies: Adults were observed in early May, and larvae were controlled by dry-based injections after about 10 days of incubating larvae in mid-May.
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