Pine wood nematode disease, also known as pine wilt disease, is a devastating epidemic of pine trees. In China, the pine brown tianniu is its main media insect, with strong pathogenicity, fast death of the host, rapid spread, and often caught off guard, once it occurs, it is difficult to manage. Pine wood nematode disease mainly occurs in China on black pine, red pine and masson pine. Miao Zhenwang, a 110 expert of Shanxi Agricultural Science and a senior engineer of Shanxi Forestry and Grassland Pest Prevention and Quarantine Station, made a detailed interpretation of the distribution of pine wood nematode disease and prevention and control measures, and asked farmers and friends to pay attention to it in time.
Miao Zhenwang
Senior engineer of Shanxi Forestry and Grassland Pest Prevention and Quarantine Station, 110 expert of Shanxi Agricultural Science
Distribution
The distribution hazards of pine wood nematode disease at home and abroad are as follows:
Pine wood nematode disease is mainly distributed in Japan, the United States, Canada, South Korea, France, Russia, Mexico, Portugal and other countries.
Pine wood nematode disease was first discovered in Nanjing, Jiangsu Province, China in 1982. In the past 40 years, the disease has spread rapidly in China, the adaptability has gradually increased, and the degree of harm has gradually deepened. As of December 31, 2020, pine wood nematode disease outbreaks occurred in 18 provinces (districts and cities), 718 county-level administrative regions, and 5479 township-level administrative regions in Jiangsu, Zhejiang, Jiangxi, Shandong, Hubei, Hunan, Guangdong, Guangxi, Fujian, Anhui, Sichuan, Chongqing, Yunnan, Guizhou, Liaoning, Shaanxi, Henan, Tianjin, etc., in China. The outbreak area of the epidemic is 27.1382 million mu, and the number of sick and dead pine trees is 19.4703 million, which seriously threatens china's pine forest ecosystem and has a serious impact on China's ecological security.
Pine wood nematode disease has not been found in Shanxi in recent years, but Henan, Shaanxi and Tianjin around Shanxi Province have been endangered, and the nearest epidemic area and county are less than 50 kilometers away from our province in a straight line, especially since 2017, the fact that the epidemic has occurred in some counties in Liaoning Province, which has a relatively cold climate, has issued a serious warning to our province, and the area north of Taiyuan, which was originally considered to be an inappropriate area for pine wood nematode disease, has become a suitable area, and the vector insects that spread pine wood nematode, Pine brown Tianniu and spruce flower ink Tianniu, have a natural distribution in the pine forest of our province. All pine trees in the province from south to north may be invaded by pine wood nematodes, with frequent trade exchanges, pine wood nematodes may invade our province at any time by transporting infected pine wood, pine products, optical cable pine plates and other goods, posing a major threat to the existing more than 29 million mu of pine forests in Shanxi Province, and the prevention and control situation is very severe.
Prevention and control measures
1. Strengthen monitoring and census
(1) Monitoring scope: all pine trees in the jurisdiction, focusing on pine trees along the power grid and communication lines, near the construction areas of communication base stations, highways, railways, hydropower and other construction projects, around timber distribution centers, scenic spots, and adjacent areas of the epidemic area.
(2) Monitoring time: Conduct regular inspections of pine trees in the jurisdiction, at least once a month.
(3) Monitoring content: investigate whether there are abnormal conditions such as pine tree death and pine needle discoloration.
(4) Monitoring methods
Survey: According to the distribution of local pine forests, a trail can be designed to observe all forest stands. Take visual inspection methods or use telescopes to investigate whether there are dead pine trees along the path of walking, or pine trees with symptoms such as fading, yellowing, wilting, and reddish-brown color. Once abnormal conditions such as pine tree death and discoloration of pine needles are found, samples should be taken immediately to confirm whether they are infected with pine wood nematode disease. Once infection with pine wood nematode disease is confirmed, a detailed investigation should be carried out immediately.
Remote sensing survey: the use of aerospace remote sensing technology to monitor and investigate a large area of pine forest, once the abnormal situation is found, after the use of GPS calibration geographical location, manual ground survey and sampling identification are carried out to confirm whether it is infected with pine wood nematode disease. Once infection with pine wood nematode disease is confirmed, a detailed investigation should be carried out immediately.
Trap investigation: suitable for the monitoring of forest stands in non-occurring areas of pine wood nematode disease, and it is strictly forbidden to use it in the junction area of non-outbreak area and occurrence area. Traps are set up during the feathering stage of vector insects to lure vector insects, and the adult adult insects trapped are cut (or cultured) indoors for isolation and identification to confirm whether pine wood nematodes are carried. Once a pine wood nematode is found, it should be examined immediately.
Detailed investigation: For pine forests that confirm the occurrence of pine wood nematode disease, investigate in detail the location of the epidemic, the type of host, the occurrence area (in small classes, the actual area of the occurrence cannot be counted in small classes, and the occurrence area of the pine trees on the four sides is counted in a converted manner), the number of sick and dead pine trees, the status of the forest stand, and the causes of occurrence, etc., and accurately locate the diseased and dead pine trees, and draw a schematic map of the distribution of the epidemic situation and the detailed map of the epidemic small class. When investigating the number of diseased and dead trees, the dead pine trees and dying pine trees in the small class of the epidemic should be included in the diseased and dead pine trees for investigation and statistics.
2. Epidemic census
(1) Census scope: all pine trees in the jurisdiction.
(2) Census time: 2 times a year. The spring census is conducted from March to June and the autumn census is conducted from August to October.
(3) Census content: Investigate whether the pine trees in the jurisdiction have died, pine needle discoloration and other abnormal conditions.
(4) Census method: monitoring with the epidemic situation. Among them, the small class that has been confirmed to have an epidemic situation will be directly investigated in detail.
3. Strict quarantine measures
Strict re-inspection of pine and its products from the epidemic area, especially the re-inspection of pine and its products such as cable trays, optical cable trays, and wooden packaging materials, and the epidemic situation or suspected epidemic situation should be dealt with on the spot.
Strengthen the quarantine supervision of enterprises and individuals that transfer, use and operate pine wood and its products within the jurisdiction, grasp the operation and use of their products involving wood-related optical cable trays and wooden packaging, carry out key monitoring of transfers from epidemic areas outside the province, and promptly sample and quarantine when suspicious symptoms are found. Units involved in the operation, use or transportation of pine wood and its products should strengthen internal management, report for inspection in a timely manner according to law, and do not use wood products that have not passed quarantine.
4. The epidemic situation has been removed
The uprooting of pine wood nematode disease epidemic adopts the prevention and control strategy of cleaning up diseased and dead pine trees as the core measures, and taking vector insect drug control, trapping traps, punching injection, etc. as auxiliary measures, scientifically formulating the epidemic uprooting plan, accurately selecting and using relevant auxiliary prevention and control technologies, strengthening quarantine blockade, and strictly supervising diseased trees to ensure the effectiveness of prevention and control.
(1) Removal of diseased wood
Selective logging: Suitable for all outbreaks of forest stands, concentrated in the winter and spring vector insects non-feathering period, all diseased and dead (dead, near-death, etc.) pine trees in the small class of outbreaks are harvested. According to the needs of epidemic prevention and control, the selective logging range can be extended outward by 2000 meters. After selective logging, all branches with a diameter of more than 1 cm above the ground of the logging site should be cleaned, and the pine trees and cleaned branches should all be crushed or destroyed on the spot. If the feathering period of vector insects is earlier than the end of March, the eradication task can be completed before the end of March due to the needs of epidemic prevention and control, but stricter measures must be taken to prevent the loss of diseased wood in accordance with the requirements of the same day of harvesting pine trees that must be destroyed on the spot on the same day.
Clear logging: In principle, no clear logging is taken, and measures can be taken for isolated epidemic sites with an area of less than 100 mu and can achieve no epidemic situation in the same year. In the non-feathering period of winter and spring vector insects, and the feathering period is earlier than the end of March, the eradication task can be completed before the end of March due to the needs of epidemic prevention and control, but it must be in accordance with the requirements of the same day of harvesting pine trees must be destroyed on the spot, and more stringent measures must be taken to strictly prevent the loss of diseased wood. After clearing, all branches with a diameter of more than 1 cm above the ground of the logging site should be cleaned up, and all the pine trees and cleaned branches should be crushed or destroyed on the spot.
Pile cutting treatment: The height of the pile must not exceed 5 cm. After the diseased wood is cut down, 1-2 aluminum phosphide grains can be placed on the pile, and then a set of plastic film bags with a thickness of more than 0.8 mm can be added, and the plastic film bags are compacted around the soil (the minimum temperature during the treatment period is not less than 10 °C); it can also be burned, crushed, and steel wire mesh cover (steel wire diameter ≥ 0.12 mm, mesh ≥8 mesh) and other methods.
Diseased wood treatment: crushing (chipping) treatment, applicable to all epidemic areas, the use of crushing (chipping) machine to crush or slice the diseased wood, the particle size of the crushed matter does not exceed 1 cm, the thickness of the chipping does not exceed 0.5 cm; burn treatment, suitable for the cleaning of the diseased wood is small and does not have the conditions for crushing and chipping the epidemic treatment area, the nearest selection of fire safety open space to harvest the diseased wood, more than 1 cm of branches all burned, and the whole process of burning treatment is photographed and archived; steel wire mesh treatment, for the steep slope of the mountain, There is no road, inaccessible, and can not take crushing, burning and other treatment measures of special places, you can take measures such as in-situ steel wire mesh cover, in addition to the above situation, it is strictly forbidden to use, the treatment method is to use a steel wire diameter of ≥0.12mm, mesh ≥ 8 purposes of steel wire mesh cover to wrap the diseased wood, and lock the edge.
(2) Vector insect control
Pharmaceutical control: suitable for pine wood nematode disease control area and prevention area. Scattered pine forests can be controlled by aircraft administration, and scattered pine trees can be controlled by ground spraying. After determining the control area according to the needs of vector insect control, at the beginning of vector insect feathering and the end of the effective period of the first spray, the high-efficiency, low-toxicity, eco-friendly sustained-release agent was selected for two consecutive aircraft or ground sprays for control.
Trap control: Pine forests that are suitable for the central area of the forest stand where the epidemic occurs and the vector insect population density is high, and it is strictly forbidden to use it in the junction area of the epidemic area and the non-occurrence area. Set up traps 1-5 days before the feathering of vector insects, generally every 30 acres can be set up, the distance between each one is about 150 meters, and GPS positioning, draw location diagrams. The trap should be set in a relatively open and well-ventilated area in the forest as much as possible, the trap should be suspended vertically, the lower end should be about 1.5 meters from the ground, and the core should be replaced in time to count the amount of vector insect enticing.
Vertical lure wood prevention and control: applicable to the central area of the epidemic exclusion of small classes, it is strictly forbidden to use in the pine forest near the edge of the small class where the epidemic occurs. In the early stage of vector insect feathering, weak pine trees are selected in the occurrence area as enticing wood, and the trap is stripped and cut out of the trap, and the attractant can be injected. 1 plant can be set up every 10 acres, and the number and GPS positioning of the trap tree are set up, and the lure wood is cut down and crushed, sliced or burned every winter and spring.
Perforation injection: Suitable for famous ancient trees and pine trees that need to be protected in parks, scenic spots, temples and other areas.
Editor: Shi Huifang Wang Dawei Review: Shen Hongtao
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