Causes and control methods of yellowing leaves followed by dieback and death in flowering peach (Prunus persica)
After the leaves of planted flowering peach turn yellow, the branches dry up and then the plant dies. What is the cause? How can it be controlled?
① Improper care: prolonged waterlogging in the planting site or pot, watering at noon, poor water quality, overly high concentration of topdressing, excessive raw fertilizer or base fertilizer, and overly shady conditions can all cause death. ② Pests and diseases: a. Gummosis and dieback disease (cankers and branch blight). A type of branch blight, mostly occurring from April to June; leaves turn yellow first, then the branches dry up and the plant dies. b. Leaf blight. Mostly occurring from April to May; diseased leaves turn yellow and thicken, with small red spots scattered on the underside, and from July they begin to fall or dry up, with severe cases causing the whole plant to die. c. Crown gall. Infection begins at an air temperature of 20°C; examination of the roots reveals tumor-like growths, mostly occurring under conditions such as continuous cropping and artificial mechanical injury that allow bacteria to invade and cause damage. d. Damage by mites, aphids and scale insects causes weakened growth and reduced resistance, leading to death.
Control methods: ① Gummosis and dieback disease: a. After heavily pruning the diseased branches, apply sulfur powder to the cut surfaces. b. Spray 1:1:160 Bordeaux mixture or 5-degree lime sulfur mixture or arsenic-containing solution every 7 to 10 days for control. ② Leaf blight: refer to gummosis and dieback disease. ③ For mites, aphids and scale insects, use 15% aldicarb and bury 20 to 40 granules to kill them.
Control methods: ① Gummosis and dieback disease: a. After heavily pruning the diseased branches, apply sulfur powder to the cut surfaces. b. Spray 1:1:160 Bordeaux mixture or 5-degree lime sulfur mixture or arsenic-containing solution every 7 to 10 days for control. ② Leaf blight: refer to gummosis and dieback disease. ③ For mites, aphids and scale insects, use 15% aldicarb and bury 20 to 40 granules to kill them.