[Distribution and Hazard] The disease occurs in Pinus koraiensis plantations in the three northeastern provinces. Yanji, Hunchun, Helong, Wangqing, Dunhua, Antu, Longjing and other cities (counties) in the Yanbian area of ​​Jilin Province have a severe disease incidence. The general incidence rate is 20% to 30%, and the incidence of severe disease stands is 50% to 60%. Individual forest stands at Maoershan Forest Farm in Yanji City have an incidence of 98.6%.
The bacteria invaded the phloem and cambium of the young trunk and lateral branches of the cedar, and even reached the xylem on the surface of the sapwood, causing the tissue brown to rot and die, which seriously affected the growth of diseased trees, and some of them caused death. According to the survey, the height loss of serious disease trees was 51.1%, and the loss of DBH growth was 42.4%. Due to the depression of trunk disease, timber defects and affecting timber production are important diseases that harm the young plantations of Pinus koraiensis.
[Symptoms] The germs invade the trunk and lateral branches from the skin wounds. After the collaterals were infested, the phloem turned brown and rotted, and local lesions began to form. The appearance of the whole shoots did not change, and peeling examination could be found. The bacteria quickly expanded their branches and the needles turned yellow and green. The whole branch withered in the spring of the second year and there were lipid droplets in the diseased and healthy borders. The main site of the trunk is mostly the dry skin at the base of the diseased side branch or mechanical damage. At the early stage of disease, there was no obvious change in the epidermis of the diseased part, and the phloem was cut off and turned brownish. After reaching the depth of the phloem, many rosins are continuously spilling from the lenticels and the drips stick on the bark. The diseased area expands horizontally around the trunk into a ring rotten skin, and develops up and down and cortical deep. Infected saplings have been in continuous onset for many years. As the medical history prolonged, the overflowing lipids accumulated more and more, and the epidermis of the diseased epidermis covered a layer of lipids. Severely diseased trees that have been in continuous disease for several years, the diseased part can be as long as 50 ~ 60cm, even up to 1m. Due to the destruction of the diseased cambium and the loss of proliferative capacity, the diseased parts of the trunk gradually become hollow, and the rotten skin shrinks and cracks rough and brown. At its worst, the trunk is thick and thin. When the formation layer of the rotten part of the rotten skin completely rots, the seriously ill sap will die, and it will appear dead in April and May. By mid-June, the papillary brown pseudomons and conidia were densely planted on dead branches and dry skin. Natural diseases, mostly dry branches, produce mostly fruiting fruit bodies. Sexual and asexual mixed together, the naked eye is not easy to distinguish. Severe disease lived in the dry skin of the diseased section of the tree, but also scattered asexual and sexual fruiting bodies, while the genitals were mostly covered by lipids, and the lipid layer was severely inspected (Cai version 14).
[pathogen] The pathogenic type Leucostomakunzei (Fr.) Munk of the pathogenic bacteria forms a prosthetic seat with a flat-topped conical shape. It was initially buried in the skin and then penetrated through the epidermis and was exposed. The inside is composed of dirty white loose tissue. There are 4 More than 30 oval-shaped ascospora shells are closely arranged at the bottom. As the neck gathers together, the papillary opening is exposed outside the bark to form a disk-like outer seat. The boundaries between the prosthesis and the host organization are clear, and the base edge has a black line. The seat width is 882-1311μm. It is 694 to 977 μm high and 240 to 700 μm wide. The asccus shell has an oval, long-necked, leathery, mature brown or brown color, 244-330 μm in size, 289-366 μm in length, 599-688 μm in length, and 3355 μm in thickness. Ascospore rod-shaped, thin wall, colorless, the middle slightly thick, the top obtuse, the lower end tapering, sessile, size 21.3 ~ 27.5μm4.3 ~ 5.0μm. There are 8 ascospores inside, arranged in irregular double or triple rows. Ascosporosporids, single spores, colorless, size 7.0 to 7.8 μm 1.0 to 1.5 μm.
The anamorphous conidia are spherical or oblate spheroids, brown carbonaceous, initially buried in the skin, after breaking through the epidermis, leaving only the orifice exposed. The chamber is irregular and multi-chamber communicating with a common orifice. The width is 696 to 1035 μm and the height is 614 to 864 μm. Conidiophore periwinkles in organs, branched, with 1 to 3 times dichotomously branched, apically tapered, colorless, undivided, size 19.4 to 32.4 μm long, coarse 1.1 to 1 .6μm. The conidia are sausage-shaped, single spores, and colorless, with a size of 3.0-5.1 μm and 0.6-0.9 μm.
The spore germination and colony growth of the bacterium in a variety of media such as PDA is rapid, and the conventional method is easy to obtain pure bacteria by tissue and spore separation. The colony was white-matted at the beginning and was brownish-brown. After about 25 days of light culture at 23 to 27°C, a granular conidiospore was produced on the surface of the colony, mostly solitary and white, then matured and browned after 10 to 20 days, and the opaque connate spore angle overflowed from the orifice. .
The germination temperature of ascospores and conidia is in the range of 15-30°C, and the optimum temperature is 20-25°C. The temperature range for colony growth is from 5 to 35°C and the optimum temperature is 25°C. The germination pH value of ascospores and conidia was 3.5 to 8.5, and the optimum was 4.5 to 6.0. The colony grows in a pH range of 3.0 to 8.0 and optimally 3.5 to 4.0. The spore germination rate is closely related to the nutritional conditions. Ascospores and conidia do not germinate when they are drip-cultured with fresh water. After incubation at 25°C for 48 hours, the medium used 2% agar and the germination rate was 53%; with agar 2% plus pine juice, 98%, the germination rate was 78.6%; with agar 2% and potato juice 78%, The 20% germination rate of Jiasongpi juice was 91.8%. When the nutrients are abundant, conidia germinate and turn round, and ascospores form a gourd shape. Poor nutrition, conidiospores and ascospores germinated when elongated oval or thicker elongation, buds from both ends of the spore or one end grow.
Using pure bacteria and spore suspensions obtained by isolation and culture, seedlings such as Pinus koraiensis, Pinus thunbergii, Pinus densiflora, Pinus sylvestris var. mongolica, Larix olgensis, etc. were inoculated with holes, acupunctures, and burns. In addition to the inoculation of Korean pine, the incidence rate of diseased plants was 100%. Inoculation of other tree species did not occur. From the inoculation to the occurrence of rotten skin lipids incubation period of about 100 days.
[Influence] The bacterium is matured and immature in the prosthesis, conidia, and hyphae. After the end of April, when the average temperature reached 10°C or more, on mature days, mature prostheses and conidiospores released spores, which spread by wind and rain and were the primary source of infection for the disease. At the beginning of June, dry branches of diseased branches, stems, and severe diseased trees were newly formed in the year to form new prostheses and conidia, and they gradually matured to release spores at the beginning of July, and were the source of repeated infections of the disease. The spore propagation period lasts from 5 months to the end of September. The amount of spores transmitted is closely related to rainfall, temperature, and humidity. From mid-June to late July, the rainfall is large, and the temperature and humidity are high. The spores are prosperous and the peak of several transmissions occurs during this period. The microscopic examination of the spores and microscopy of slides in forests shows that the generation and maturation of the sexual and asexual fruit bodies of the bacteria are not neat, and the maturation of the ascomy capsules and the maturation of the individual ascomas in the same ascular capsule are within the same subunit. The period is not neat. As the ascus matures, the disintegration of the wall dissolves and a large number of individual ascospores and many ascospores are seen in the mature ascaria shell. Sick saplings, from July to the third year of the year, can release sexual and asexual spores.
The occurrence and prevalence of the disease are closely related to the age of the forest, the aspect of the slope, the composition of the soil, the stand composition, the degree of canopy closure, the growth of trees, and management measures. The age of forest can be 10 to 30 years old and the incidence of forests from 15 to 25 years old is severe. Sunny slopes and semi-sunny slopes are more serious than those on cloudy slopes; pure forests are more serious than mixed forests. The weight of soil with heavy soil and low available nitrogen content was heavy. Trees with a canopy density of about 0.8 have a light incidence, while those with excessive canopy density result in poor growth and heavy disease. Forests with small canopy closures, due to strong sunlight in the forest, are conducive to the occurrence of pests such as Pinus koraiensis and Pinus sylvestris , which results in many tiny wounds in the dried forest skin, which facilitates the invasion of the disease. Therefore, the disease is also severe, and long after afforestation Without thinning and thinning, many of the forests that are being severed and smashed to death, or thinning and tending to be carried out too late, and some forests with unreasonable intensity of pruning, the incidence of such stands is severe. In the meantime, the thinning of trees with a canopy density of about 0.8 was carried out in a timely manner. Therefore, all the factors that cause the poor growth of forest trees and the production of a large number of wounds in debilitated trees are the causes of the occurrence and prevalence of the disease.
ã€Control measures】 The pathogen is a weak parasitic bacterium, and the prevention and control methods are based on forest management measures and supplemented with chemical control. The management of Pinus koraiensis plantations should be strengthened, and the thinning should be conducted in a timely manner in accordance with the growth and development laws of young forests to maintain the appropriate density, improve the forest sanitation environment, and increase the tree vigor to prevent the occurrence of the disease. According to the survey, the rough skin type of Korean pine is not only fast growing, but also has a stronger resistance to lipomatosis. Emphasis should be placed on the breeding of resistant and fast-growing red pine superior varieties to provide production applications. Afforestation should be appropriate to the trees and vigorously create mixed forests.
Combining thinning and thinning of diseased stands, stems and deadly diseased trees, the diseased forests are transported out of the forest and burned off to reduce the source of infection. For the diseased trees preserved, NaOH1% plus Ca(OH)225% aqueous solution was used to scrape the rotten skin in the spring to obtain the desired effect. When scraping the skin, care should be taken to protect the formation layer and scrape it to the border between the sick and the health. The scope of the applicator should be extended to a depth of 5 to 10cm. Strict operation, after the first year of prevention and control can control the disease damage, the second year of appropriate treatment can be cured. This method is especially suitable for seriously illed saplings with a DBH diameter of less than 10 cm, and the trees are safe and free from injury. Can also be used pine tar, pine tar plus diesel 1:1, chlorothalonil 10% oil coating treatment, all get better results. However, attention should be paid to the use of oil paints to prevent and treat severely saplings that are more than 50 cm in length. They are prone to phytotoxicity and may even die, and can be applied in stages.
The bacteria invaded the phloem and cambium of the young trunk and lateral branches of the cedar, and even reached the xylem on the surface of the sapwood, causing the tissue brown to rot and die, which seriously affected the growth of diseased trees, and some of them caused death. According to the survey, the height loss of serious disease trees was 51.1%, and the loss of DBH growth was 42.4%. Due to the depression of trunk disease, timber defects and affecting timber production are important diseases that harm the young plantations of Pinus koraiensis.
[Symptoms] The germs invade the trunk and lateral branches from the skin wounds. After the collaterals were infested, the phloem turned brown and rotted, and local lesions began to form. The appearance of the whole shoots did not change, and peeling examination could be found. The bacteria quickly expanded their branches and the needles turned yellow and green. The whole branch withered in the spring of the second year and there were lipid droplets in the diseased and healthy borders. The main site of the trunk is mostly the dry skin at the base of the diseased side branch or mechanical damage. At the early stage of disease, there was no obvious change in the epidermis of the diseased part, and the phloem was cut off and turned brownish. After reaching the depth of the phloem, many rosins are continuously spilling from the lenticels and the drips stick on the bark. The diseased area expands horizontally around the trunk into a ring rotten skin, and develops up and down and cortical deep. Infected saplings have been in continuous onset for many years. As the medical history prolonged, the overflowing lipids accumulated more and more, and the epidermis of the diseased epidermis covered a layer of lipids. Severely diseased trees that have been in continuous disease for several years, the diseased part can be as long as 50 ~ 60cm, even up to 1m. Due to the destruction of the diseased cambium and the loss of proliferative capacity, the diseased parts of the trunk gradually become hollow, and the rotten skin shrinks and cracks rough and brown. At its worst, the trunk is thick and thin. When the formation layer of the rotten part of the rotten skin completely rots, the seriously ill sap will die, and it will appear dead in April and May. By mid-June, the papillary brown pseudomons and conidia were densely planted on dead branches and dry skin. Natural diseases, mostly dry branches, produce mostly fruiting fruit bodies. Sexual and asexual mixed together, the naked eye is not easy to distinguish. Severe disease lived in the dry skin of the diseased section of the tree, but also scattered asexual and sexual fruiting bodies, while the genitals were mostly covered by lipids, and the lipid layer was severely inspected (Cai version 14).
[pathogen] The pathogenic type Leucostomakunzei (Fr.) Munk of the pathogenic bacteria forms a prosthetic seat with a flat-topped conical shape. It was initially buried in the skin and then penetrated through the epidermis and was exposed. The inside is composed of dirty white loose tissue. There are 4 More than 30 oval-shaped ascospora shells are closely arranged at the bottom. As the neck gathers together, the papillary opening is exposed outside the bark to form a disk-like outer seat. The boundaries between the prosthesis and the host organization are clear, and the base edge has a black line. The seat width is 882-1311μm. It is 694 to 977 μm high and 240 to 700 μm wide. The asccus shell has an oval, long-necked, leathery, mature brown or brown color, 244-330 μm in size, 289-366 μm in length, 599-688 μm in length, and 3355 μm in thickness. Ascospore rod-shaped, thin wall, colorless, the middle slightly thick, the top obtuse, the lower end tapering, sessile, size 21.3 ~ 27.5μm4.3 ~ 5.0μm. There are 8 ascospores inside, arranged in irregular double or triple rows. Ascosporosporids, single spores, colorless, size 7.0 to 7.8 μm 1.0 to 1.5 μm.
The anamorphous conidia are spherical or oblate spheroids, brown carbonaceous, initially buried in the skin, after breaking through the epidermis, leaving only the orifice exposed. The chamber is irregular and multi-chamber communicating with a common orifice. The width is 696 to 1035 μm and the height is 614 to 864 μm. Conidiophore periwinkles in organs, branched, with 1 to 3 times dichotomously branched, apically tapered, colorless, undivided, size 19.4 to 32.4 μm long, coarse 1.1 to 1 .6μm. The conidia are sausage-shaped, single spores, and colorless, with a size of 3.0-5.1 μm and 0.6-0.9 μm.
The spore germination and colony growth of the bacterium in a variety of media such as PDA is rapid, and the conventional method is easy to obtain pure bacteria by tissue and spore separation. The colony was white-matted at the beginning and was brownish-brown. After about 25 days of light culture at 23 to 27°C, a granular conidiospore was produced on the surface of the colony, mostly solitary and white, then matured and browned after 10 to 20 days, and the opaque connate spore angle overflowed from the orifice. .
The germination temperature of ascospores and conidia is in the range of 15-30°C, and the optimum temperature is 20-25°C. The temperature range for colony growth is from 5 to 35°C and the optimum temperature is 25°C. The germination pH value of ascospores and conidia was 3.5 to 8.5, and the optimum was 4.5 to 6.0. The colony grows in a pH range of 3.0 to 8.0 and optimally 3.5 to 4.0. The spore germination rate is closely related to the nutritional conditions. Ascospores and conidia do not germinate when they are drip-cultured with fresh water. After incubation at 25°C for 48 hours, the medium used 2% agar and the germination rate was 53%; with agar 2% plus pine juice, 98%, the germination rate was 78.6%; with agar 2% and potato juice 78%, The 20% germination rate of Jiasongpi juice was 91.8%. When the nutrients are abundant, conidia germinate and turn round, and ascospores form a gourd shape. Poor nutrition, conidiospores and ascospores germinated when elongated oval or thicker elongation, buds from both ends of the spore or one end grow.
Using pure bacteria and spore suspensions obtained by isolation and culture, seedlings such as Pinus koraiensis, Pinus thunbergii, Pinus densiflora, Pinus sylvestris var. mongolica, Larix olgensis, etc. were inoculated with holes, acupunctures, and burns. In addition to the inoculation of Korean pine, the incidence rate of diseased plants was 100%. Inoculation of other tree species did not occur. From the inoculation to the occurrence of rotten skin lipids incubation period of about 100 days.
[Influence] The bacterium is matured and immature in the prosthesis, conidia, and hyphae. After the end of April, when the average temperature reached 10°C or more, on mature days, mature prostheses and conidiospores released spores, which spread by wind and rain and were the primary source of infection for the disease. At the beginning of June, dry branches of diseased branches, stems, and severe diseased trees were newly formed in the year to form new prostheses and conidia, and they gradually matured to release spores at the beginning of July, and were the source of repeated infections of the disease. The spore propagation period lasts from 5 months to the end of September. The amount of spores transmitted is closely related to rainfall, temperature, and humidity. From mid-June to late July, the rainfall is large, and the temperature and humidity are high. The spores are prosperous and the peak of several transmissions occurs during this period. The microscopic examination of the spores and microscopy of slides in forests shows that the generation and maturation of the sexual and asexual fruit bodies of the bacteria are not neat, and the maturation of the ascomy capsules and the maturation of the individual ascomas in the same ascular capsule are within the same subunit. The period is not neat. As the ascus matures, the disintegration of the wall dissolves and a large number of individual ascospores and many ascospores are seen in the mature ascaria shell. Sick saplings, from July to the third year of the year, can release sexual and asexual spores.
The occurrence and prevalence of the disease are closely related to the age of the forest, the aspect of the slope, the composition of the soil, the stand composition, the degree of canopy closure, the growth of trees, and management measures. The age of forest can be 10 to 30 years old and the incidence of forests from 15 to 25 years old is severe. Sunny slopes and semi-sunny slopes are more serious than those on cloudy slopes; pure forests are more serious than mixed forests. The weight of soil with heavy soil and low available nitrogen content was heavy. Trees with a canopy density of about 0.8 have a light incidence, while those with excessive canopy density result in poor growth and heavy disease. Forests with small canopy closures, due to strong sunlight in the forest, are conducive to the occurrence of pests such as Pinus koraiensis and Pinus sylvestris , which results in many tiny wounds in the dried forest skin, which facilitates the invasion of the disease. Therefore, the disease is also severe, and long after afforestation Without thinning and thinning, many of the forests that are being severed and smashed to death, or thinning and tending to be carried out too late, and some forests with unreasonable intensity of pruning, the incidence of such stands is severe. In the meantime, the thinning of trees with a canopy density of about 0.8 was carried out in a timely manner. Therefore, all the factors that cause the poor growth of forest trees and the production of a large number of wounds in debilitated trees are the causes of the occurrence and prevalence of the disease.
ã€Control measures】 The pathogen is a weak parasitic bacterium, and the prevention and control methods are based on forest management measures and supplemented with chemical control. The management of Pinus koraiensis plantations should be strengthened, and the thinning should be conducted in a timely manner in accordance with the growth and development laws of young forests to maintain the appropriate density, improve the forest sanitation environment, and increase the tree vigor to prevent the occurrence of the disease. According to the survey, the rough skin type of Korean pine is not only fast growing, but also has a stronger resistance to lipomatosis. Emphasis should be placed on the breeding of resistant and fast-growing red pine superior varieties to provide production applications. Afforestation should be appropriate to the trees and vigorously create mixed forests.
Combining thinning and thinning of diseased stands, stems and deadly diseased trees, the diseased forests are transported out of the forest and burned off to reduce the source of infection. For the diseased trees preserved, NaOH1% plus Ca(OH)225% aqueous solution was used to scrape the rotten skin in the spring to obtain the desired effect. When scraping the skin, care should be taken to protect the formation layer and scrape it to the border between the sick and the health. The scope of the applicator should be extended to a depth of 5 to 10cm. Strict operation, after the first year of prevention and control can control the disease damage, the second year of appropriate treatment can be cured. This method is especially suitable for seriously illed saplings with a DBH diameter of less than 10 cm, and the trees are safe and free from injury. Can also be used pine tar, pine tar plus diesel 1:1, chlorothalonil 10% oil coating treatment, all get better results. However, attention should be paid to the use of oil paints to prevent and treat severely saplings that are more than 50 cm in length. They are prone to phytotoxicity and may even die, and can be applied in stages.
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