Hou Po is a traditional Chinese herbal medicine that has been used for the treatment of digestive disorders. It also has sedative effects and has been found to be effective in the prevention and treatment of viral hepatitis, liver fibrosis, and cirrhosis. The Hou Po variety grown in Enshi City is particularly renowned. In this article, we will explore some common pests that occur during the cultivation of Hou Po and their control methods.
1. Brown longhorn beetle
The brown longhorn beetle is a common and major pest of Hou Po. It belongs to the family Cerambycidae and is also known as the "old woodworm" in local dialects.
(1) Symptoms of infestation
The larvae of the beetle initially bore into the bark and feed on the cambium layer. After about 5-7 weeks, they move towards the central woody part of the tree and continue feeding, creating irregular curved tunnels. This can affect the transportation of water and nutrients, leading to a decline in the tree's vigor. In severe cases, the entire tree gradually withers and dies.
(2) Pest behavior
One generation of the beetle is completed in 2 years, with the larvae overwintering in the tunnels and under the bark. In the following spring, they pupate inside the tunnels and emerge as adults around early summer. The adults hide in the tunnels during the day and come out to mate and lay eggs in the tunnels and scars about 1 meter above the ground. The larvae initially feed underneath the bark for 5-7 weeks before moving into the woody part of the tree.
(3) Control methods
① Manual killing: During the peak period of adult activity from May to July, manual killing can be conducted. Check the tree trunk and use a wire hook to kill the newly hatched larvae and remove egg masses and early-stage larvae. In the early morning, inspect the tunnels on the trunk and use a wire hook to kill the adults. ② Sealing and poisoning: Soak cotton with 5% diazinon solution and stuff it into the tunnels, then seal the openings with mud to poison the larvae.
2. Brown-edged and brown sawflies
The newly hatched larvae of these sawflies feed on the undersides of leaves, and as adults, they scatter and feed on the entire leaf. In severe cases, they can completely defoliate the tree.
Control methods
① Remove the mature larvae that form cocoons on the ground in autumn. In the winter and spring seasons, remove the cocoons in the soil around the tree base to reduce the pest population for the following year.
② Remove leaves with eggs and newly hatched larvae and burn them in a centralized manner.
③ Spray 90% dichlorvos solution at 800 times dilution and Bt emulsion at 300 times dilution during the early larval stage for chemical control.
3. Green tortoise beetle
The adult beetles of the green tortoise beetle feed on the leaves of Hou Po, causing irregular holes and severe damage can result in complete defoliation, especially on hot, windless nights.
Control methods
Remove weeds around the Hou Po plants in early winter and deeply till the soil to eliminate and kill overwintering larvae. In late winter to early spring, mix 1-5 kg of zinc-sulfur-phosphorus with 15 kg of soil and spread it on the ground before tilling to kill the larvae. During the early stage of infestation, spray 90% dichlorvos solution at 1000-1500 times dilution. In heavily infested areas, set up 40-watt blacklights and floodlights to attract and kill the green tortoise beetles.
4. Termites
Termites mainly damage the roots of the trees.
Control methods
Locate the main tunnels of the termites and pour lime water or smoke to kill them. If possible without damaging the roots of the Hou Po tree, excavate the nests and use mosquito killer powder to kill the termites.
