Since the beginning of autumn, temperatures have gradually dropped, and various garden plants have ended their summer dormancy and entered their peak autumn growth phase. This is also the peak period for pests and diseases, with many leaf-eating pests hatching into larvae, feeding heavily on leaves, and then spinning cocoons to overwinter. Therefore, effective autumn pest and disease control is crucial to reduce the pest population for the following year and ensure normal leaf growth in garden plants. Cool-climate lawns have also weathered the hot and humid summer and are entering another vigorous growth period full of new life. Therefore, autumn is also an important season for the prevention and control of pests and diseases in garden plants.

I. Aphids

Aphids are important pests of garden plants, mainly occurring in spring and autumn. As autumn temperatures drop, some aphids begin to fly to their hosts to prepare for overwintering. They easily induce sooty mold, which can cause the death of garden plants in severe cases. Major aphids in autumn include the white poplar aphid, cypress aphid, peach aphid, cotton aphid, rose long-tubed aphid, autumn four-veined cotton aphid, and black-haired aphid.

Prevention and control methods:

1. In conjunction with plant pruning, remove branches containing insect eggs;

2. During the peak egg-laying period before overwintering, spray with pesticides for control. For example, spray with one of the following: 1.2% nicotine EC at 800-1000 times dilution; 6% imidacloprid EC at 3000-4000 times dilution; 5% acetamiprid EC at 5000-6000 times dilution; 50% phoxim EC at 800-1000 times dilution; or 2.5% deltamethrin at 2500-3000 times dilution. Take safety precautions when spraying. Oxymethoate is also a good pesticide for controlling aphids, but it may cause phytotoxicity to Rosaceae plants such as peach blossoms, elm-leaf plums, and flowering quince. Therefore, use with extreme caution on garden plants and avoid using it if possible.

3. Pay attention to protecting and utilizing various natural enemies, and do not use broad-spectrum pesticides during the peak hatching period of natural enemies.

4. Applying 100 grams of 3% carbofuran granules per square meter directly to the root zone of some flowering shrubs can also effectively control aphids.

II. Woodworms

Autumn is the peak season for borer pests, such as longhorn beetles and wood-boring moths. While some longhorn beetles may still produce adults during this season, most larvae bore into the phloem and xylem of trees, continuing to excrete frass. Larvae in the phloem can remain infested until early to mid-November, while those in the xylem can infest until late November. Some wood-boring moth larvae descend from the tree to pupate or overwinter inside the tree. Major borer pests to control in autumn include: *Aegilops glabripennis*, *Aegilops mulberry*, *Aegilops spiny-horned*, *Aegilops aromaticus*, *Aegilops elm*, *Aegilops spicata*, *Sophora japonica* leafroller, and *Ailanthus altissima* weevils, among others.

Prevention and control methods:

1. Regarding longhorn beetle pests

① Killing adult beetles is the fundamental way to control them. For longhorn beetles that still exist in autumn, a second spray of 8% Green Weilei at a dilution of 300 to 400 times can be applied; adult beetles can also be manually killed.

② Autumn is the initial stage of damage caused by longhorn beetle larvae. At this time, spray the tree with a 200-300 times dilution of phoxim. If conditions permit, spray once every 10 days to effectively kill the longhorn beetle larvae. During the active period before the larvae bore into the xylem, spray the trunk with 50% fenitrothion emulsion or apply a paste.

③ For trunk injection of trees, use strong systemic pesticides such as acetamiprid, imidacloprid, or dimethoate, injecting 1 ml per 1 cm of tree diameter at breast height.

④ In the planning and design, attention should be paid to mixed planting of trees to avoid single tree species being harmed by the same longhorn beetle, thereby reducing the damage and spread of the longhorn beetle.

2. For wood-boring moths

①Strengthen management, enhance tree vigor, and remove severely damaged branches and trunks to reduce the source of insects;

② Install insecticidal lamps to attract and kill adult insects;

③ Spraying to kill newly hatched larvae: For newly hatched larvae that have not yet burrowed into the trunk, spray with 50% phoxim EC at a dilution of 1000-1500 times or 40% dimethoate EC at a dilution of 1500 times. Both methods are effective.

④ Inject pesticides into the larvae's holes to kill them. For middle-aged and older larvae that have already burrowed into the trunk, inject pesticides into the holes using a veterinary syringe. Systemic pesticides such as 40% dimethoate EC at a dilution of 40-60 times or 80% dichlorvos EC at a dilution of 20-30 times can be used.

⑤ Tree trunk injection: Use 6% imidacloprid EC or 5% acetamiprid EC, inject 1 or 1.5 ml per 1 cm of tree diameter at breast height, which can effectively prevent adult insects from laying eggs and prevent larval damage inside the tree trunk.

III. Stink Bug Pests

Stink bugs belong to the order Hemiptera. Both adults and nymphs feed by sucking the leaves of garden plants, causing chlorosis and stunted growth. They generally overwinter as adults, and in autumn, most begin to seek hiding places to prepare for hibernation. If control measures are not timely, severe infestations often lead to sooty mold. Major stink bug pests in autumn include the mottled stink bug, the tea-winged stink bug, the spotted-edged stink bug, and the amber stink bug.

Prevention and control methods:

① During the overwintering period, adults can be manually captured or their dead branches, fallen leaves, and weeds can be removed and burned to eliminate overwintering adults.

② Spray with 6% imidacloprid EC at a dilution of 3000-4000 times, or 50% phoxim EC at a dilution of 800-1000 times, or 2.5% deltamethrin EC at a dilution of 2500-3000 times, or 1.2% nicotine EC at a dilution of 800-1000 times, etc.

③ Protect natural enemies, such as lacewings and spiders.

IV. Tussock moths

Tussock moths are a major pest of garden plants, feeding on a wide variety of leaf-eating tree species. Severe infestations can defoliate entire leaves, hindering the formation of winter buds. Autumn is the peak season for the second generation of tussock moths, and also the time when most tussock moths pupate and overwinter. Major tussock moths include the flat-spotted tussock moth, the two-instar green tussock moth, the brown-edged green tussock moth, and the yellow tussock moth.

Prevention and control methods:

1. Manually remove or break the cocoons on the tree trunk to reduce the source of insects.

2. When larvae congregate and cause damage, remove the infested leaves and manually kill the larvae, taking care to avoid the poisonous hairs of the larvae during the killing process.

3. Before the larvae reach the 3rd instar, use biological agents, such as a 500-700 times dilution of Bt wettable powder with a concentration of 16000 IU/mg.

4. Chemical control. For young larvae, use biomimetic pesticides such as 25% diflubenzuron suspension at 1500-2000 times dilution, 25% chlorfluazuron suspension at 2000-3000 times dilution, or 20% chlorpyrifos suspension at 1500-2000 times dilution. For large-scale larval infestations, spray with pesticides such as 20% deltamethrin at 2000-3000 times dilution, 2.5% deltamethrin at 1500-2000 times dilution, 50% phoxim EC at 1000-1500 times dilution, or 1.2% nicotine EC at 800-1000 times dilution.

5. Protect natural enemies, such as the purple tussock moth wasp, mantis, and stink bug.

V. Other leaf-eating pests

Autumn is the peak season for the larvae of various leaf-eating pests to damage the leaves of various trees. Many pests often erupt in autumn, some overwintering as young larvae, and others as eggs or cocoons. Therefore, after a branch or leaf is depleted, they disperse to feed, affecting the formation of winter buds and causing dormant buds to sprout again. Major pests include the poplar leafroller moth, the horned tussock moth, the ailanthus bark moth, the pepper swallowtail butterfly, the cotton leafroller, the bagworm moth, the grape tiger moth, the grape hawk moth, the willow blue leaf beetle, the ailanthus silkworm moth, the inchworm, and the fall webworm.

Prevention and control methods:

1. Horticultural techniques for prevention and control:

① You can rake the soil, weed, or turn the ground around the trees to kill the pupae that are preparing to overwinter;

② Take advantage of the larvae's tendency to fall when startled, either by knocking them down when they appear, or by manually killing the larvae on the tree based on the insect droppings and debris on the ground and leaves.

③ After the larvae enter the soil or before the adults emerge, spray or irrigate the ground around the host to kill the pupae in the soil.

2. Physical control: Utilize the phototaxis of adult moths to attract and kill adults with black light lamps during the adult emergence period, thereby reducing the number of eggs laid.

3. Biological control: Before the larvae reach the 3rd instar, apply a 1000-1200 times dilution of Bt wettable powder with a concentration of 16000 IU/mg. This protects natural enemies and prevents environmental pollution.

4. Chemical control: For larvae in the 3rd to 4th instar, spray with 20% diflubenzuron suspension at a dilution of 3000-3500 times, or 25% cypermethrin suspension at a dilution of 2000-2500 times, or 20% chlorpyrifos suspension at a dilution of 1500-2000 times, etc., which are biomimetic pesticides. When the insect population density is high, spray with 50% phoxim at a dilution of 2500 times, or 2.5% deltamethrin EC at a dilution of 2500-3000 times, or 2.5% deltamethrin at a dilution of 2000-3000 times, etc., all of which have good control effects.

5. Protect natural enemies such as mantises, wasps, braconid wasps, and beneficial birds.

VI. Scale insects

Scale insects, also known as bark beetles, belong to the superfamily Scaleoidea of ​​the order Hemiptera. Besides directly damaging host plants by piercing and sucking their flesh, they also excrete sap that can induce sooty mold, causing weakened plant growth, flower and fruit drop, branch dieback, or even the death of the entire plant. Major scale insects found in autumn include the crape myrtle scale, the euonymus scale, the persimmon scale, the boxwood scale, and the cottony cushion scale.

Prevention and control methods:

1. Strengthen plant quarantine. Scale insects live a fixed life and can spread to other places with seedlings. Therefore, when introducing seedlings, quarantine should be strengthened to ensure that the introduced seedlings do not carry scale insects.

2. Proper pruning and shaping: Scale insects often gather on the branches of the plant. The plant can be pruned and shaped in winter to change the habitat of the scale insects, thereby reducing the damage caused by the scale insects. The pruned branches with insects should be collected and burned.

3. Chemical control: During the peak hatching period of nymphs, before or just as a waxy layer has formed, spray the branches and leaves with a 2000-fold dilution of 6% imidacloprid soluble liquid, a 4000-fold dilution of 2.5% deltamethrin EC, or a 4000-5000-fold dilution of 5% acetamiprid EC. Alternate between these three agents, spraying once every 7-10 days, for 2-3 consecutive applications. The key to effective spraying is timing (the nymphal stage). If the nymphs have formed a fixed waxy shell, a 1500-2000-fold dilution of 40% imidacloprid EC can be applied, both of which will yield good results.

4. Pay attention to protecting and utilizing natural enemies such as the red-ringed ladybug and the black-edged ladybug.