Spring Pest and Disease Control Methods for Protected Plum Trees
1. Mound soil at the base of the trunk. Before overwintering adults emerge from the soil (mid to late May), build a 10 cm thick mound of soil around the tree basin and tamp it down firmly so that emerging adults cannot come out of the soil. 2. Apply pesticide to the ground. Before overwintering adults emerge (after petal fall), spray the tree basin with 75% phoxim emulsifiable concentrate at 0.5 kg/mu, or 40...
1. Improve light. In the greenhouse, measures such as suspending fruiting branches, rational pruning and laying reflective film can be used to improve ventilation and light penetration and reduce the incidence of pests and diseases. ① Rational pruning. On each main scaffold branch extension head, keep only one appropriately oriented vigorous first or second flush shoot, and remove the rest. Cut back overly vigorous fruiting branches, leaving only one flat or slanting new shoot in front of the fruit spur shoot. Promptly prune out diseased and insect-infested branches and thin out non-fruiting branches. Properly shorten some shading new shoots. Sweep up fallen leaves and fruit and burn or deeply bury them. ② Suspend fruiting branches. First use No. 16 iron wire to form a 2 x 2 m grid in the greenhouse at 1.8 m above the ground, then use thin rope to pull the drooping long fruiting branches up to the canopy as slanting upright branches, move the long fruiting branches into spaces lacking branches, and tie the thin rope to the wire. ③ Lay reflective film. Through branch suspension and pruning, leave a 0.3-0.4 m wide light-transmitting band between rows, and under the light-transmitting band lay a single layer of 1 m wide aluminum foil reflective film.2. Reduce humidity. Cover the ground with plastic film in the protected facility, and after the plum pit-hardening stage use ventilation to reduce humidity, furrow irrigation and hole irrigation under the film, appropriately raise the greenhouse temperature, and promptly drain accumulated water and take other measures to lower relative air humidity, increase fruit transpiration rate and reduce the occurrence of diseases.
3. Prevent and control diseases. Before plum trees bloom, the branches are prone to infection by gummosis, which weakens the twigs, makes flower buds weak, and makes fruit set difficult; in severe cases the twigs dry up and cannot bloom or bear fruit. Therefore, pay attention to inspecting the plum tree twigs. If gummy material is found oozing from the twigs, scrape it off with a small knife, then apply a layer of lime-sulfur mixture residue, or Bordeaux mixture, or 25% soda ash aqueous solution, or 1% potassium permanganate aqueous solution. Before flowering, spray the inner twigs 1-2 times with 0.6-0.8 degrees Baume lime-sulfur mixture aqueous solution or 600-fold copper oxychloride aqueous solution to kill pathogens attached to the branches, which can control infection of plum branches by gummosis before flowering.
After the young calyxes of plum fruit fall off, in combination with foliar fertilization, spray a mixture of 70% mancozeb wettable powder 1000-fold solution and 50% carbendazim wettable powder 1000-fold solution once every 10-15 days to control shot-hole disease and others. When spraying fungicides, if red spider mites occur, mix in 15% pyridaben emulsifiable concentrate 2000-3000-fold solution or 1.8% abamectin 4000-5000-fold solution. If aphids occur, mix in 10% imidacloprid wettable powder 3000-4000-fold solution.
4. Prevent and control insect pests. At bud break, spray with 20% yamiejing emulsifiable concentrate 1000-1500-fold solution, or 10% beta-cypermethrin emulsifiable concentrate 2000-4000-fold solution, or 50% tuijunte wettable powder 800-1000-fold solution, which can effectively control overwintering aphids and also has good repellent and control effects on scarab beetles and others. After leaf expansion, in combination with foliar fertilization, spray a mixture of 70% mancozeb 800-1000-fold solution and 50% carbendazim wettable powder 1000-fold solution once every 10 days to prevent disease and protect leaves. When spraying fungicides, if aphids or moths occur, mix in 20% yamiejing emulsifiable concentrate 1000-1500-fold solution; if red spider mites occur, mix in 15% pyridaben emulsifiable concentrate 2000-3000-fold solution, or 1.8% abamectin 4000-5000-fold solution. Apply 1.5% phoxim granules at 5 kg per mu to control white grubs and other underground pests.
5. Avoid mixed planting. Avoid mixed planting with other stone fruit trees to prevent the mutual spread of pests and diseases.