Pear trees are planted in all regions, no matter what kind of fruit trees, we must do a good job of pest prevention. There are many diseases and insect pests in the process of pear tree planting, among which the pests that eat the branches of pear trees are extremely harmful. Let's take a look at the occurrence law and control methods of the four kinds of dried moth pests in pear trees!
First, the blue and yellow-eyed tianniu
The blue-yellow-eyed celestial calf, also known as the semi-yellow celestial calf, belongs to the coleoptera family. Mainly for pear trees, apples, bonuses, begonias and other fruit trees 2 to 4 years of branches, it especially likes to endanger the new branches issued above the graft interface. The phloem is collected by the larvae, and the branches are covered with a layer of tobacco-like fibers after being killed.
Propagation rules:
A generation occurs every two years, overwintering as larvae, pupating at the end of February, feathering in mid-April, laying eggs in late April, and hatching larvae in early May. Adults are active for about 20 days. The eggs are laid under the skin of 2- to 3-year-old branches, and an inverted scar of 11 mm long and 6 mm wide is formed at the spawning site. The larvae feed on xylem and phloem, forming strips of moths and pushing the strips of wood chips out of the skin, sometimes biting through the phloem to form flocculent clumps. Heavily damaged trees, scars and flocculents are strewn with branches.
Prevention and control methods:
1. During the emergence of adult insects, catch adult insects.
2. Adult spawning period and larval incubation period, spray 80% dichlorvos emulsion 1000 times liquid or 2.5% dichlorvos emulsion 2000 to 3000 times liquid every 10 days, and can also spray octyl thiophos, urea, fruit worm net and other pesticides to kill adults, eggs and larvae.
3. Where tobacco-like flocculents are found on the branches, immediately use a knife to scrape open the victim and stab the larvae.
Second, the star sky bull
Xingtian cattle, also known as white star tianniu, silver star tianniu, dry root tianniu, belongs to the coleoptera family. It mainly harms the trunk of pear, apple, peach and other fruit trees.
One or two-year complete generation occurs each year, with larvae overwintering inside the trunk. The pupae appear in may, eating twigs and shoots. Adults lay eggs in September, and most of the eggs are laid on the main trunk 30 to 80 cm from the ground. Before spawning, bite a lip-shaped groove on the bark, about 1 cm long, and then insert the laying tube into the groove to lay an egg, the egg is embedded in the skin slit, and then the groove is longitudinally split into a "t" shape, the egg is located in the crack, and the egg stage is 9 to 15 days. The hatched larvae circle under the bark of the tree, gradually penetrating deep into the xylem and feeding down to the roots, while mothing an air hole outward for excretion and ventilation. The moths are irregularly curved and filled with woody feces, which are also found in the borer holes.
1. Kill adult insects during the adult occurrence period.
2. In the spawning period of adult worms, often check the trunk, if there is spit-like glue, immediately use a knife to pick out the eggs and crush them. At the same time, carefully spray around the trunk once 50% octylthion emulsion 1000 times liquid or 20% emulsion cypermethrin 3000 times liquid, or 3000 times kung fu, 1000 times dichlorvos liquid, in order to culling eggs and larvae that have just hatched but have not fallen into the tree.
3, after the larvae moth into the trunk, where there is fresh feces outside the borer hole, there must be live larvae inside, the use of fine steel wire and bamboo skewers into the borer hole to stab the worm to death, the stab can not be dipped in a cotton ball 400 times the enemy into the moth hole, or with 1 gram of cattle spirit stuffed into the borer hole, the outside is then coated with soft mud, the worm poisoned in the hole.
3. Wood brown wood beetle moth
The wood brown wood beetle moth, also known as the willow dry wood beetle moth and the black beetle moth, belongs to the lepidoptera wood beetle moth family. Mainly endanger the main trunk of pear, apple, peach and other fruit trees, with larvae under the trunk cortex moth, moths around the trunk of the trunk is a ring peeling, very irregular, and then moth into the xylem, affecting the fruit tree on the transport of water and nutrients, so that the tree weakens or even dies.
A generation is completed in 2 to 3 years, with larvae overwintering in the trunk. Adults occur from June to July, mostly feathering at night, and have phototropism. The eggs are laid in a crack in the trunk 1.5 m above the ground, and the newly hatched larvae are mothed into the cortex, and a large amount of reddish-brown coarse moist feces and brown sap flow out of the borer hole. The larvae are 16 years old.
The control method is the same as that of Xingtian cattle.
Fourth, pear-striated giddings
Pear-veined giddings, also known as string-skin worms, belongs to the coleoptera gidding family. The main harm to pear trees is that the larvae eat phloem and form layers under the trunk and large branch bark, cut off the nutrient delivery channel and cannot form secondary xylem, causing the plant to die. Yunnan began to be discovered in the early 1970s, and has now spread to Kunming, Xundian, Qujing, Lufeng, Luxi and other places, several pear orchards have been destroyed by this insect, and has now become a dangerous pest of pear trees in Yunnan.
One generation occurs a year, with larvae overwintering in the densurge tunnels of the branch cortex. Activities begin in February of the following year, with the peak of the hazard in March and xylem pupae in May. Adults appear from late May to early June, prefer sunlight, are extremely active at noon, eat leaves, lay eggs under the branches, hatch larvae in mid-June, and gradually moth into xylem after mid-August, endangering a period of time into overwintering.
1. Ovulation spraying at the spawning stage with 80% dichlorvos emulsion 1000 times liquid or 2.5% cypermethrin emulsion 2500 times liquid, can be sprayed once every 10 days, focusing on the main trunk and large branches, in order to culling adult insects, eggs and larvae that have just hatched out but have not been mothed into the branches.
2. When the pupa is about to feather into an adult worm and has not dried, scrape off the outer coarse skin, burn it centrally, and then use 1 part of methyl enemy powder or imidacloprid powder, mix 300 parts of glue mud or slime slurry, carefully paint the trunk, and seal it and poison it in the bark.
3. When the larvae are in full bloom in March to April and when the larvae are just mothed into the formation layer in July, mix well with 50% emulsion octylthiophos and 30 parts of diesel fuel to brush the victim. Before painting, scrape off the coarse skin, and then cut it with a fast knife every 3 to 4 cm, deep into the wood, so that the liquid penetrates into the formation layer and kills the larvae hidden under the phloem.
4, tobacco smoke to kill the pear garden far from the village, in the spawning period of adult insects out of the tree, every 5 to 7 days, at night in the garden to burn a "diagonal amoax" (forest pest control drugs, forestry department plant protection units are sold), with the smoke in the poison gas poisoning adult insects. Pear orchards close to the village cannot use this method to avoid poisoning of people and animals.
These four are common pests in pear trees, and if they are present, they will cause harm to the branches of fruit trees, and if they are serious, they will cause death to pear trees. The control methods of these pests have also been introduced above, hoping to help the majority of pear tree growers.