There are many branches and leaves in the canopy that turn yellow and dry. But on the surface, there are no obvious pests and diseases on these trees, only some wounds on the trunk. What's going on?
From the symptoms of tree damage and the wounds on the trunk, it can be basically determined that the main reason for the yellowing and drying of branches and leaves is the harm of dry moths. First, half a kilogram of chlorpyrifos + half a kilogram of silicone is mixed with 15 kilograms of water, and the trunk is sprayed as a whole, using the smell of the drug to smoke out the pests hiding inside the trunk.
Shortly after the potion was applied, many small red bugs emerged from the wormholes in the trunks, and after comparison, it was found that they were the larvae of the wood beetle [dù] moth!
What is the wood beetle moth?
The wood beetle moth is actually a general term for a variety of insects in the lepidoptera wood beetle moth family. The occurrence of wood beetle moths varies from generation to generation depending on the species and region, mostly 2 years and 1 generation or 1 generation per year, the generations are not neat, and often the larvae of various insect ages exist at the same time, which brings certain difficulties to the control work.
Larval active period: Larvae are in harm from March to October.
Adult winging period: April to July adult emergence.
Wood beetle moth overwinters in the trunk with larvae, begins to recover in March, and enters the peak of harm in April; at the same time, April is also the feathering period of adult insects, adults lie diurnal and nocturnal, mating and laying eggs, each laying dozens to more than a thousand eggs, and a new generation of larvae follows in large numbers.
1. In what form is the hazard?
In the process of garden maintenance and forestry pest control, the wood beetle moth mainly carries out moth damage in the form of larvae in the trunk or branches of seedlings, and mainly lives on the phloem and formation layer of moth-eating plants.
2. What kind of seedlings are the main hazards?
Wood beetle moth mainly harms broad-leaved tree species in gardens,
The main species of wood beetle moth that are more common in China are as follows:
1. Distribution of oriental subspecies of aromatic wood beetle moth: northeast, northwest, north China, east China, central China, southwest China. Hosts: Willow, poplar, elm, locust, birch, ash, oak, walnut, toon, apple, pear, sea buckthorn, maple genus.
2. Distribution of elm beetle moth: Northeast, Northwest, North China, East China, Central China. Hosts: Elm, Plum, Willow, Poplar, Locust, Plum, Oak, Cloves, Ginkgo Biloba, Apple, Walnut, Peppercorn, Honeysuckle.
3. Distribution of the small-lined wood beetle moth: Northeast China, North China, East China, Central China, Shaanxi, Ningxia and other places. Host: ash, willow, locust, dragon's claw locust, ginkgo biloba, plane tree, toon, magnolia, yuanbao maple, cloves, hemp oak, apple, begonia, hawthorn, elm leaf plum, etc.
3. What are the characteristics of the hazard?
The damage mainly occurs in the larval stage, generally with several or dozens of larvae under the bark to bite the phloem and forming layers around, and then transferred to the xylem to drill into an irregular tunnel, on the surface of the bark to discharge piles of insect feces, insect feces are powdery or fine. After the damage, the plant channeling tissue is cut off, and the affected part is not easy to recover, resulting in the weakening of the tree year by year, followed by the formation of dry shoots and dry decay, which seriously leads to the death of the whole plant.
Symptoms of trees that are harmed by the wood beetle moth?
Since the larvae of the wood beetle moth generally start from the branches and then slowly transfer to the trunk and roots, the seedlings that are harmed by the larvae of the wood beetle moth generally show the phenomenon of withering and drying up first, and then find worm holes with insect feces on the branches and trunks.
How to prevent the harm of wood beetle moths to seedlings?
Physical control: including light trapping adults, artificial control of larvae and pupae, through artificial pruning and rational forest management, improve the resistance of trees to insect pests.
Biological control: Spray or plug hole control can be used in some strains of the genus Albicans or insect pathogen Nematodes.
Chemical control: It is recommended to choose high-efficiency and low-grade gastric toxicity, contact insecticides and agents with penetrant as an auxiliary agent, through the method of spraying, spraying or brushing, so that the agent penetrates into the dry skin tissue, prevention and control of dry borers that harm the phloem and xylem shallow layers, and the best control time for chemical control is the young larval stage.
How to control seedlings that have been harmed by wood beetle moths?
(1) For seedlings that have been harmed by wood beetle moths, the harmful branches will be pruned and destroyed to avoid further spread of pests.
(2) For branches that are inconvenient to prune, wire and other larvae in the insect path can be used.
(3) During the harmful period of the wood beetle moth from March to October every year, it is optional to use a cotton swab dipped in 80% of the dichlorvos emulsion 100 times liquid to directly stuff it into the worm hole, and then seal it with mud; You can also use a needle tube to inject the solution directly into the worm hole and seal the hole with clay.
(4) For seedlings that mainly harm the trunk, you can use half a kilogram of chlorpyrifos + half a kilogram of silicone, mixed with 15 kilograms of water, and spray the trunk directly.
(5) In October of each year, when the mature larvae of the aromatic wood beetle moth leave the trunk and enter the soil to pupate, the larvae can be killed by manual hunting. It is also possible to sprinkle poisonous sand and water during this period, and apply some touch-type insecticides to the roots to kill these mature larvae that are ready to pupate in the soil.
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