Author: Hancheng Forestry Station Liang Yanwei Dang Wenhong
Pepper flow gum disease
Peppercorn gum disease, in the Weibei production area is more common, generally from the middle of March began to occur, pepper tree infection with gum disease, nutrient guidance tissue damage, tree weakness, the ability to resist natural disasters declined, affecting yield and plant life, is currently the main disease that harms pepper trees.
1. Harmful symptoms
The disease mainly harms the main trunk of the pepper tree, especially the base of the trunk's neck, and in severe cases, the upper branches of the canopy also produce spots. In the early stage of the disease, the disease spots are not obvious, the epidermis of the victim is reddish brown, with the expansion of the spots, the lesions are wet and rotten, the epidermis is slightly sunken, and accompanied by the appearance of glue, continue to develop the spots black, a large area of bark rot, so that the transportation of nutrients to the tree body is blocked, resulting in yellowing and withering of the diseased branches and leaves, when the spots are surrounded by a week, the upper branches of the spots dry and die, and even the whole plant dies.
a Disease causes flow gum b Worm infestation causes flow glue
Figure 5-10 Hazards of glue disease
2. Pathogenesis
The pathogen overwinters in the diseased tissue with mycelium and propagulants, and can infect pepper trees from March to October of the following year. When the temperature slowly rises, reaching between 15 and 25 ° C, the disease spots begin to recover and expand, and the diseased part produces conidia that spread through rain and invade by the wound. Under natural conditions, most pepper trees that are harmed by gidding insects have fluid gum disease. Generally in the middle of March to late May, the onset of the disease is relatively slow, from mid-July to mid-August the disease develops rapidly, spreads rapidly, the disease can develop until October, when the temperature drops, the disease stops developing. The rainy, hot season (or year) is conducive to the occurrence and spread of diseases.
Da Hong Pao pepper is susceptible to this disease, and the disease-resistant varieties of bean pepper and wild varieties of Gou pepper and stink pepper have mild or no disease. The incidence of young trees is mild, and the incidence of cold and cool mountains is mild. In general, areas with a lot of water or rain and pepper orchards with poor pest control are more severe.
3. Cause of incidence
3.1. Dried moth pests are mainly wounds caused by peppercorn narrow gidding that are prone to fluid gum disease.
3.2. Parasitic fungi and bacteria parasitize the branches and leaves to harm, so that the growth of pepper trees is weak and the resistance is reduced.
3.3. Wounds caused by mechanical damage, frostbite, sunburn, excessive trimming during the growth period, and wounds caused by excessive weight.
3.4. Poor scion, unfriendly rootstock, poor soil is too viscous or acidic.
3.5. Poor drainage, improper irrigation, and excessive water in the ground area.
4. Prevention and control methods
Figure 5-11 Wound management
4.1. Strengthen the management of pepper orchards
(1) Reasonable fertilization From January to June, nitrogen, phosphorus and potassium fertilizers are the mainstay, and organic fertilizers are increased at the same time to improve soil permeability and enhance the disease resistance of trees.
(2) Reasonable pruning Remove diseased and insect branches in time by pruning, reduce the chance of secondary infection, rationally lay out branches, control results, and make the tree strong.
4.2. Tree protection Diseases mainly invade from wounds, do a good job of mechanical damage, insect pests, diseases and other wound treatment, reduce the occurrence of diseases and insect pests. For wounds caused by pruning, apply fruit rot in time. Avoid injuring large roots when performing deep ploughing operations, reduce non-impregnated diseases, or wrap the trunk to reduce the chance of adults laying eggs at the base of the trunk.
4.3. Variety improvement Select the rotten pepper with developed root system and strong resistance as the rootstock, and graft the good varieties such as 'lion's head', 'thornless pepper', 'Nanqiang No.1', 'Early Red' and 'Yellow Cover' to improve the resistance of peppercorns and reduce the occurrence of gum disease. Grafting methods such as budding, grafting, and rootgrafting can be used.
4.4. Timely drainage During the rainy season, the accumulated water of low-lying terrain is removed in time to maintain the permeability of the soil.
Fig. 5-12 Grafting improvement
4.5. Pharmaceutical control
(1) Winter Qingyuan The branches and leaves of diseases and insects are burned or buried deeply, and before germination in early spring and after the leaves fall in late autumn, spray once with 3 to 5 baumedo stone sulfur compound or 150 to 200 times mineral oil or equivalent Bordeaux liquid to prevent and control overwintering diseases.
Fig. 5-13 Stone sulfur compound is whitened
(2) Tree trunk painting Whitening During the winter dormancy period (the minimum temperature is above 5 °C), the trunk is whitened to prevent frost damage.
(3) Scraping off the disease spots Found that there is a glue flow case with a wooden stick or rubber hammer hammer to hit the glue part, to ensure that the gidding worm is hammered to death, scraping off the rubber scar or rotten skin, with 1.8% caprylamine acetate 100 times + 40% chlorpyrifos 100 times + 10% imidacloprid 100 times the mixture to apply the hammering site, or with cloth strips soaked in medicine wrapped around the base of the trunk, the outside is wrapped with newspaper or kraft paper to ensure that the drug is absorbed by the tree body; when it is found that there are borer holes in the branches, seal the mouth with poisonous mud and poison sticks, and smoke the moths Scraped rubber scars or rotten skins should be taken out of the pepper garden, buried deep or destroyed.
Fig. 5-14 Narrow giddings