What are the main pests of mountain walnuts? What are the occurrence rules and prevention and control technologies of the main insect pests of mountain walnut? Before the Small Editor of Huinong Network has brought you a variety of mountain walnut cultivation technology, today we will talk about the main pests and occurrence of mountain walnuts and prevention and control.
1 The main pest of mountain walnut and its occurrence law
1.1 Borer pests
Walnut lifting moth is a kind of larvae moth to eat walnut green fruit, causing green fruit to fall off, resulting in a reduction in yield of a pest, the re-occurrence area hazard rate can be as high as 100%, the green fruit damage rate can reach more than 70%, and in severe cases, it can cause some walnut trees to fail. The pest occurs in 1-2 generations a year at an altitude of 1200 m. The larvae of the walnut lifter moth overwinter mainly by forming cocoons in the soil, and then begin feathering in mid-to-late June of the following year, and the peak of spawning and feathering for the walnut lifter moth in mid-july. Walnut lifting moth lays eggs at the seams of the fruit, fruit stalks, etc., the egg stage is generally 5-7 days, and the walnut lifting moth larvae break off the fruit in mid-to-late August of the year and enter the soil to prepare for wintering.
The walnut long-legged elephant is one of the main pests that harm walnut fruit, mainly larval and adult pests. Walnut longfoot elephant mainly through the walnut fruit inside, nibbling on the fruit, the victim walnut fruit can be seen in the inner peel exposed and black, the kernel is underdeveloped, more than 40 worm holes can be seen on the fruit in severe cases, the victim rate of serious walnut forest can be as high as 80%, the damage rate of green fruit can reach 60%, causing a large number of fruits to fall off, and even no grain harvest. Walnut longfoot is a pest of one generation a year, adults mainly overwinter on the soil surface and the weeds on the upper slope, and wake up in mid-may of the following year, mainly feeding on young shoots and petioles, resulting in dry and shedding of new leaves, entering the spawning period in early June and entering the peak of incubation in mid-June, which is the walnut longfoot larvae drilling out of the fruit, and endangering the walnut green fruit, and entering the wintering period in November of that year.
1.2 Harmful to branch pests
Cloud-spotted tianniu larvae is one of the main pests that harm walnut branches, the pest feeds on young branches, and causes harm to walnut trees by burrowing into the xylem and phloem part of walnut trees, thereby making walnut trees lose their technological value, reducing the economic value of walnut planting, and in severe cases, causing the whole tree to die. The larvae are 2 years and 1 generation, the adults and larvae are overwintering in the trunk, the larvae become adults in mid-to-late May every year, and eat the young branches and leaves of the year, and the injured branches are broken by the wind and appear in an inverted umbrella shape. The cloud-spotted cattle worm lays eggs in June and July and hatches that year, after which the hatched larvae begin to nibble on wood and overwinter in the worm tunnel inside the walnut tree, continuing to harm the tree in the coming year.
The walnut giddings larvae are one of the main pests that harm the branches of walnut trees, which mainly harm branches that are 1 to 2 years old. Walnut gidding larvae mainly burrow into the branches and string circles, resulting in the nutrient transport channel of walnut trees being cut off, resulting in the trunk and canopy of walnut trees shrinking year by year due to lack of nutrients, affecting walnut production. After the main trunk of the young tree is endangered, the aboveground part dries up, and because the underground root system is not harmed, the tree will have branches born and die. In addition, the leopard wood beetle moth will also cause harm to walnut branches, mainly harmful to 1 to 5 years old branches, the affected branches are mostly due to the marrow heart is gnawed dry hollow branches, the damage rate is as high as 20% to 30%, and the serious case can reach 50%.
1.3 Leaf-eating pests
Ginkgo silkworm moth larvae usually feed on walnut leaf leaves, there are reports showing that the ginkgo giant silkworm moth larvae disaster area, each walnut tree can see more than 200 larvae, the leaves of the affected walnut tree are often eaten a light, the tree is branch bald fruit falling phenomenon, not only will cause a large reduction in walnut production, but also cause 10% of the walnut trees in the affected walnut forest to die. The Ginkgo giant silkworm moth is a pest of one generation a year, which mostly overwinters in the form of insect eggs, and the eggs hatch in mid-May of each year, and the larvae grow into adults after 36 to 58 days of growth. From mid-June to early July, the Ginkgo giant silkworm moth begins to pupate on branches, weeds and shrubs. It begins to feather in August to September of that year, and after feathering, it crosses the tail and lays eggs.
2 Control of the main pest of mountain walnut
2.1 Physical control
Physical control refers to the purpose of preventing and controlling insect pests through physical means, combined with local realities, it should be implemented from the following aspects: First, it is necessary to clean up orchards. After the walnuts are ripe, timely bury and burn the fruit, dead branches and leaves and weeds caused by the insect infestation to cut off the source of insects; the second is to deeply turn the tree tray, because most of the pests are overwintering in the soil, in order to eliminate the pests, it is possible to carry out deep flipping of the walnut forest in the autumn, winter, early spring, and autumn, destroying the wintering site of the pest, to achieve the purpose of eliminating the pests and diseases; the third is to remove the old disease bark in time, and to whiten the trunk of the walnut tree, smash the eggs, and incinerate the old diseased bark that has been removed. The fourth is to cut the dry dead branches, and at the end of each year, all the dry branches on the walnut tree are pulled clean and burned immediately, which can eliminate the overwintering larvae of the walnut small gidding insect and the leopard-grain wood beetle moth.
2.2 Pharmaceutical control
The main measure of pharmaceutical control is to achieve the purpose of killing pests by giving chemical agents through various channels, mainly including the following measures: (1) Chemical ground blockade. Before mid-May, sprinkle 25% parathion capsules on the canopy and soil surface at an amount of 0.5 kg/667 m2, or 5% octyl thiophos powder, 2% methamophos powder, 1.5 to 2.5 kg/667 m2. After application, the light rake is mixed with the medicinal soil, which can prevent the walnut lifting moth and the walnut long-legged elephant from overwintering and unearthing adult insects. (2) Apply poison rings and tie poison ropes. Taking advantage of the habit of the ingginkgo silkworm moth's elderly larvae to rest at 11 a.m. and go up to the tree at 3 p.m., a poison ring or a poison rope was applied to the trunk to prevent the killing of insects.
2.3 Biological control
The method of pest control using the mutually reinforcing relationship that exists in ecosystems is called biological control. Mainly including the following aspects: one is to treat insects with bacteria, specific measures are to spray 1 : 100 times the liquid of white zombie bacteria or 1 ~ 200 million / ml Suyunjin bacteria liquid during the pest hazard; the second is to treat insects with insects, you can use the natural enemies of the ginkgo giant silkworm moth, such as black egg bees, red-eyed bees, etc. for prevention and control, through the introduction of black egg bees, red-eyed bees, etc. to eliminate the eggs and larvae of the ginkgo giant silkworm moth; the third is to treat insects with birds, birds are mostly fed by pests, and the birds that are often treated are large, magpies, sparrows, etc. The number of birds can be increased by measures such as protecting birds and achieving the purpose of eliminating pests.
The above is the control measures for common insect pests of mountain walnuts, I hope it will be helpful to farmers who have planted mountain walnuts!