What are the control methods for the Asian longhorned beetle?
The Asian longhorned beetle, also known as the Asian long-horned beetle, is an important forestry pest. Its larvae bore into and feed on tree trunks, while the adults bite and feed on leaves or the bark and xylem of small branches, causing massive losses of timber every year and gradually killing trees within 3 to 5 years. This formidable forestry pest can be tackled with the great spotted woodpecker. Let's take a look below at how to control the Asian longhorned beetle!
Agricultural control
Select and breed pest-resistant varieties, plant at a reasonable density, and prune appropriately to improve ventilation and light penetration. Collect pruned diseased and pest-infested branches and burn them centrally to reduce the occurrence of the pest. Strengthen tending and management, fertilize reasonably, and apply more phosphorus and potassium fertilizer to make the plants grow vigorously and enhance their pest resistance. May to June is the peak emergence period for adults. In the early morning when the beetles are less active, hand-pick and kill the adults. At the same time, inspect the base of the trunk to locate the egg-laying sites and notch marks of the beetle, and use a small knife to scrape off the eggs and newly hatched larvae. When the beetle larvae have not yet bored into the xylem, or are only damaging the surface layer of the wood, or their tunnels are not deep, a steel wire hook can be used to kill the larvae.
Chemical control
When pest damage is found, a syringe can be used to inject pesticide into the tunnels to kill the larvae. Commonly used are 80% dichlorvos emulsifiable concentrate at 500 times dilution or 40% omethoate emulsifiable concentrate at 30 times dilution, injected into the bore holes or used to soak cotton plugs inserted into the holes (the holes sealed externally with sticky mud), or poison sticks made with pesticides such as deltamethrin inserted into the bore holes to poison the larvae. Alternatively, 52% aluminum phosphide tablets can be used for single-tree fumigation at 1 tablet per tree, or a pit can be dug for sealed fumigation at 2 tablets per sq m. Practical trials have shown a mortality rate of 100% in all cases.
Biological control
The woodpecker is the main natural enemy of the longhorned beetle and should be actively protected and attracted. Generally, one pair of woodpeckers in 500 mu of woodland can suppress the occurrence of the longhorned beetle. The attraction method is to hang one attraction log every 150 m or so in the woodland in autumn. The attraction log should be a section of soft, heart-rotted wood, 60 cm long and 20 cm thick, with a wooden cover nailed to the top to prevent rainwater from flowing in.
Whitewashing the trunk
Mix 10 kg of lime, 1 kg of sulfur, 10 g of salt and 20 to 40 kg of water thoroughly, then brush the mixture onto the base of the trunk. This can effectively kill overwintering eggs in the bark and trunk-boring longhorned beetles, eliminating the source of the pest. Generally, the whitewashing height for street trees is uniformly 1.2 to 1.5 m, while others can be 1.2 m. The whitewashing height on the same road section should be kept consistent to achieve a neat and attractive effect. When applying the mixture, it should be neither too thick nor too thin. For bark crevices, holes, and branch forks, repeat the brushing to avoid runoff, patchy or missed application, and peeling after drying. This should be done every year after the rainy season in late autumn and early winter; a second application in early spring is best for a better effect.