In recent years, pests such as pear black spot disease, pear black spot disease, pear hibiscus, and pear stem bee have a serious tendency to occur in pear producing areas. According to past experience, prevention of disease should be early, and pest control should be small. Therefore, the larval stage of pests is a critical period for the prevention and control of pear diseases and insect pests in the early and early stages of disease occurrence. Only when the pear farmers grasp these periods, choose pesticides for symptomatic treatment and spray them in time to get twice the result with half the effort.
First, the spring prevention and control methods of pear tree pests and diseases: disease
Pear scab
1 incidence. The hyphae and the ascospores are overwintered on the bud scales, diseased fruits, and diseased leaves. It can occur from falling flowers to fruit ripening. The conidia of the pathogen mainly infect all green young tissues in the upper part of the pear tree, such as bud scales, leaves, petioles, new shoots, flowers, and fruits. The main pathological features are the formation of black mold layer in the diseased part, the mildew on the base of the inflorescence, the flower bud, and the pedicel. The leaf clusters cause the leaves to wilting and die, and the small leaf veins of the leaves are most susceptible to disease, causing a large number of leaves when severe. In the late stage of new infection, the diseased part is cracked into a rough skin-like scab. Most of the young fruit infections are early or the diseased parts are corked to form deformed fruit. The large fruit is infected with multiple sore-like depressions, often cracking. The lesions are often infected by other pathogens, causing the whole fruit to rot.
2 prevention methods. When the temperature reaches 15 °C, use 320.5% azoxystrobin and difenoconazole suspension 3,000-5000 times solution or 40% myclobutanil water to disperse 600-800 times of granules, start from the inflorescence separation period, The second control was carried out 10 days after the flowering, and the spraying effect was better after spraying 10 times every 10 days. Pay attention to the observation, when there are 3 to 5 leaves on the leaves in the whole garden from the beginning of May to July, timely spraying and prevention. From late June to early July, early-maturing pears, especially the closed-closed pear orchards, should pay special attention to the infection of black spot disease. If the prevention is not timely, the disease will form black mold layers of different sizes on the fruit surface and the fruits will be lost. value.
2. Pear black spot
1 incidence. The bacteria overwinter on the diseased branches, diseased leaves and diseased fruits. In the spring, the conidia are distributed by the wind and rain, and then conidia are transmitted to infect and infect. After the infection, the temperature starts to rise above 20 °C, and it is not easy to occur below 20 °C and above 30 °C. The new shoots, leaves, flowers and fruits of pear trees can be infected, and the young leaves are most susceptible to disease. At the initial infestation, there is a black spot on the leaf tip. If there is a black mold layer on the wet surface, that is, conidia, the small black spots are enlarged to form a piece to cause the leaves to fall early. At the beginning of the new shoot, the black ellipse was slightly sunken, and later it became a pale brown ulcer-type spot, which caused cracks in the healthy part. The young fruit is black with small round spots on the surface of the infested fruit. It gradually expands and is slightly sunken. When the fruit grows, the fruit surface is cracked and the crack can reach the heart.
2 prevention methods. Both scab and black spot disease are prone to disease when the temperature is 15 °C, but the onset temperature of melasma is 3 to 5 °C higher than that of black spot disease. Therefore, when the temperature reaches 18 °C, both diseases can be caused. Take control together. Pay attention to the work of the Qingyuan, cut off the diseased branches, pick up the ground, the diseased fruit on the tree, burned or buried the diseased leaves.
3. Pear spot disease
1 incidence. Commonly known as "chicken claw disease", it is a physiological disease caused by lack of nutrition. The pear fruit enlargement period begins to develop until the harvest, the fruit surface forms a cork layer, shaped like a chicken claw. At present, the incidence of pear varieties from yellow to pear, pear, emerald, and golden pear.
2 prevention methods. Pay attention to the application of organic fertilizer and the supplement of trace elements. In the spring and young fruit period, the application of potassium fertilizer or foliar spray of potassium is emphasized to increase the potassium nutrition level of the tree, so that the peel is thickened, the toughness is enhanced, and the crack is reduced. The leaf surface of the flower is sprayed with calcium, magnesium, boron, zinc and rare earth, and sprayed 2 to 3 times within 40 days after flowering. During the expansion period from pear fruit to maturity, spray two times of calcium nitrate plus 70% thiophanate-methyl (Kato) wettable powder 800-1000 times solution, the number of diseased fruits can be controlled within 10%.
Second, the spring prevention and control methods of pear tree pests and diseases: pests
Pear
1 is harmful. In my place, 4 to 6 generations occur every year. Winter insects overwinter in bark cracks, leaves, weeds, and soil seams. In early March, the wintering adults began to emerge when the flower buds of Pear Tree expanded, and the mid-season was the peak period of the cockroach activity, and the late stage was the end stage. The adult worms move on the twigs, sucking the juice and mating to lay eggs. The eggs are mostly produced in short fruit branches, bud marks and buds. Later generations of eggs are produced between the hairs of young tissues, the main veins in the front of the leaves, and the serrations of the leaves. The first half of the flowering period is the peak of spawning, and the egg period is 7 to 10 days. The hatched first-generation nymphs are plunged into the newly-opened flowers, and later generations are more likely to suck on the leaves and secrete mucus, overlapping generations.
2 prevention methods. In early April or 80% of flowers, most of the eggs laid by wintering adults have hatched into nymphs. This is the best time to control pear hibiscus. The medicament may be selected from the group consisting of 3.2% carbaryl cypermethrin (sparkling) microemulsion 1500-2000 times solution, or 2.8% avermectin (strong point) plus 20% imidacloprid (million purple) WP 4000 times solution. The tablet that is resistant to imidacloprid in P. sylvestris is treated with 50% pymetrozine (Fei Neng) 1000-1500 times in the first half of April and after fruit bagging.
2. Pear Stem
1 is harmful. It is a genus Hymenoptera. One generation occurred in one year, and the old larvae were used for thinning and wintering in the affected branches of the year, and the sap of the spring sap flowed. Adults move during the day and stop at the back of the leaves of the new shoots in the lower part of the tree in the morning and evening and at night. When the new shoot grows five or six leaves, it begins to lay eggs on it. When the new shoot grows out about 10 days after flowering, it enters the spawning period. In the new shoot about 6 cm, saw a small mouth, the egg is produced in the pith of the new shoot. After spawning, the first bud under the saw is sawn and sawn down 1 to 2 leaves, causing the upper part of the new shoot to wilting and breaking. From mid-May to mid-July, larvae hatch larvae in the affected branches or into the 2-year-old branches.
2 prevention methods. When a few adult worms were found in the bud stage, the 2.5% cyhalothrin microemulsion 2000 times solution and 22% gamma salt insecticidal single microemulsion 2000 times solution were used to spray the adult on the back of the new shoot tip. From mid-May to late June, spray 22% of the averaging 1500-2000 times of the single-microemulsion of the carbaryl salt to kill the larvae in the affected branch. It must be noted that pear trees with weak tree and insufficient nitrogen application should be tested first and then used in large areas to avoid burns on the edge of the leaves. This pest group has the best anti-group treatment effect.
3. Pear yellow meal
1 is harmful. Also known as pear tumor, only for pear trees, 8 to 10 generations in 1 year. The eggs are overwintered in the cracks of the bark, under the skin, and in the leaves. Hatching began in early April, and the young cubs sucked the juice at the tender skin under the skin, cracks, etc. to breed. The larvae after hatching can lay eggs in 3 to 4 days, and the egg period is about 6 days. In the middle and late June, they climb to the scorpion and stems of the fruit, and suck the juice between the two fruits. On the surface of the victim, a small yellow spot with a slight depression was formed at the beginning, and it turned into a black disease and decayed.
2 prevention methods. In the first ten days of April, 3.2% of the methicillin-cypermethrin (shining) microemulsion 2000-3000 times solution and 20% imidacloprid (wanzi) WP 1500 times solution were used, mainly spraying the cracks and the old skin of the main stem and the main branch. The buds and flowers should be sprayed evenly to kill the first generation of larvae that are overwintering.
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