Close observation is crucial for the prevention and control of diseases and pests in garden plants, and it is essential to seize the appropriate time for prevention and control.

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(2) Scarab beetles: In addition to harming pear, peach, plum, grape, apple, and citrus trees, they also harm willow, mulberry, camphor, and privet trees. Adults can be shaken off the trees and killed by feigning death, or they can be trapped by black light traps.

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(3) Fall webworm: In mid-April, overwintering adult fall webworms emerge and can be manually captured for control. Fall webworms overwinter as pupae under tree bark or on the ground in dead branches and fallen leaves. After hatching, the larvae spin webs and gather in the webs to feed on the leaves. After the leaves are eaten, the larvae move to another part of the branches and tender branches to weave a new web, which can lead to the death of the plant in severe cases.

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(4) Sophora japonica geometrid moth: In late April, the first generation of Sophora japonica geometrid moth larvae begin to cause damage. The larvae begin to hatch when the eggs turn grayish-black. The newly hatched larvae are yellowish-brown and turn green after feeding. Control should be carried out during the best period. It mainly damages Sophora japonica and Sophora oleifera, and sometimes Robinia pseudoacacia. The larvae feed on the leaves, and in severe cases, it can kill the plant.

In April, wood-boring pests begin their damaging activities, mainly including the rust-shouldered longhorn beetle, the glossy-shouldered star longhorn beetle, the ailanthus weevil, and the red-brown weevil. Besides manual injection of pesticides, control measures should be tailored to the specific habits of each pest. In addition, wood-boring moths have also begun their activity and should be controlled promptly.

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(1) Aphids: They are black in color. Adult aphids or nymphs gather on the back of plant leaves, tender stems, growing points and flowers, causing growth to become unbalanced. Leaves curl and wrinkle on the back, and the growth of the heart leaves is hindered. In severe cases, the plant stops growing and may even wither and die.

When aphids infest plants, they excrete large amounts of water and honeydew, which drip onto the lower leaves, causing fungal diseases, hindering leaf physiological functions, and reducing the accumulation of dry matter. Key aphids to control include: peach aphid, rose aphid, willow black aphid, goldenrain aphid, and cotton aphid. Caution should be exercised when using organophosphate insecticides on Rosaceae plants such as peach trees to prevent phytotoxicity.

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(2) Scale insects such as grass scale and peach scale: When they start to become active and cause damage, the main control methods are to apply poison rings, or you can choose some special scale insecticides for control.

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(3) Spotted lanternfly: Hatching begins in late June. Groups of small nymphs gather on tender branches to cause damage. We should seize the opportune time to control it. Pyrethroid insecticides of 1000 times dilution can be used.

In addition, in mid-April, it is necessary to carry out the work of burying granular agents to control spider mites and other piercing-sucking pests.

In April, underground pests such as grubs begin to appear, so timely inspections should be conducted. When the soil temperature at a depth of 10 cm reaches 5℃, they begin to rise to the soil surface, and their activity is most vigorous at 13~18℃. Above 23℃, they move to deeper soil. In autumn, when the soil temperature drops to a suitable range for their activity, they move back to the upper soil layer.

This month, some diseases are in their initial infection stage, such as powdery mildew of large-leaved boxwood and black spot of roses. Prevention is the main focus this month. The key target for control during this period is canker disease of various tree species. The main control methods are to strengthen fertilizer and water management and apply chemical control agents.