Poplar leaf-eating pests reproduce quickly, have strong latent potential, wide spread, great harm, difficult to control, once spread is very easy to cause large-scale disasters, will seriously affect the normal growth of poplar trees. In this paper, the occurrence rules and control measures of major leaf pests such as Yang ruler moth, boat moth and thorn moth are elaborated, and are for reference only.
1 Poplar moth
1.1 Occurrence
The larvae of the Yang ruler moth are small, 2.2–4 cm long. With the increase of the insect age, it gradually becomes gray-brown, and there is a nodular protrusion on each side of the second section of the abdomen of the insect body, the ventral line is white, the valve line is generally yellowish, and it can walk slowly after the back arches. Basically a generation occurs once a year, the larvae pupate will burrow into the soil under the canopy of the tree for more summer or wintering, in early March of the following year, when the soil temperature reaches more than 0 ° C at a depth of 10cm, the adults begin to feather and break out of the soil, and after two weeks, they can lay eggs, and by mid-April the larvae begin to hatch, and the mature larvae in early and mid-May pupate, the general pre-pupal period is 4-7 days, and the pupal period is up to 9 months long.
1.2 Prevention and control measures
1.2.1 Pupae. Seize the opportunity of pupae over the summer and winter, first turn the woodland deep, turn the pupae to the ground, and then concentrate on killing.
1.2.2 Lights booby trap male adults. Male adults have a strong phototropism and can be placed in black light to trap male moths.
1.2.3 Stop wingless female adults. Spread poisonous soil: Dig a circular ditch around the trunk, the wall of the ditch is smooth and straight, about 10 cm deep and wide, and the ditch is sprinkled with fine soil and a mixture of 1:1 of the borer pine. Coating the barrier ring: dilute 20% permethrin emulsion into 50 times liquid or 2.5% cypermethrin into 33.3 times liquid with diesel oil, and the ring is coated at a dry height of 1 meter; Or dilute diesel oil with 20% permethrin or 2.5% cypermethrin at 20:1, soak the kraft paper about 5 cm wide, remove and dry, and surround it at a dry height of 1 meter; Or at a dry height of 1 meter around the wide tape ring, spray green Willy 100-200 times liquid on and down the ring.
1.2.4 Pharmaceutical control. When the larvae occur in large areas, the permethrin insecticide 2000-3000 times liquid can be sprayed on low-dry larvae. For some tall trunk trees (trees more than 10 meters high), use the punch injection method: first use a punching machine to punch holes in the chest diameter of poplar trees, inject 40% sulfonus soluble liquid or 2% stingoramine 1 times the liquid per hole, and the dosage is 1 ml per centimeter chest diameter.
2 Boat moths
2.1 Occurrence
Boat moths mainly include Yang Fan Boat Moth, Yang Xiao Boat Moth, Moon Fan Boat Moth, Yang Er-tailed Boat Moth, Yang Poison Moth, Willow Poison Moth and so on. Adults of the Yang fan boat moth are gray-brown, with large brown fan-shaped spots at the apex of the forewings; The female has a thick abdomen with a hairy bundle at the end of the abdomen. Oval, orange-red, dark brown near hatching. The larvae are pale green when they hatch, gradually turn golden yellow with age, and the head is dark brown; The mature larvae are black with 8 orange-red tumors in each ring with long hairs, and the larvae have larger reddish-brown tumors in the center of the dorsal center of the 1st and 8th abdominal segments. The hatching larvae tend to cluster on the leaf surface to nibble on the leaf flesh, leaving the upper epidermis and veins to form a network of leaves. After the 2nd instar, the leaves are spit into a dumpling-shaped large insect bun, which lies in it during the day and eats at night. The amount of food eaten by the larvae increases with the age of the insect, and after the 3rd instar, the amount of food increases greatly, disperses the feeding, eats all the leaves, and only the petiole remains. When there is not enough food, the spit silk sags and drifts to other places with the wind, and then rolls the leaves. The insect reproduces quickly, has a large number and a wide distribution, and if the early control is not timely, it often eats up the leaves in a short period of time, which is very easy to become a disaster.
Adult Yang Boat Moth is grayish brown with a dark brown longitudinal band on the back of the cephalothorax; The forewings have three pale stripes and a grayish-white line in the center of the wings. The eggs are pale green. Mature larvae are nearly spindle-shaped, with a dark brown back and yellow on both sides; There are red tumors and small white dots on the back; There is a large sarcoma on the back of the 4th and 11th segments of the abdomen, with short fine hairs on the upper part. After the 4th instar, the larvae begin to disperse and move, eating the most and causing the most harm.
2.2 Prevention and control measures
2.2.1 Artificial killing of overwintering pupae. Effectively monitor the insect situation, accurately grasp the place and area of the 5th generation of larvae and the density of pupal pupa before and after wintering, and carry out artificial pupae in winter and spring to reduce the number of pupal bases and reduce the degree of occurrence.
2.2.2 Drug prevention and treatment. Drug control should be treated early and small, and the forest stands with large pupae density and potential for disaster should be prevented before the larvae are 3 years old. For 3-4 year old young trees, avermectin or 25% urea urea 2000-2500 times liquid, 40% oxidized legona emulsion 1500-2000 times liquid, or 4.5% cypermethrin 2000-3000 times liquid and other gastric toxin contact agents. For some tall trees, use the punch injection method, first use the punching machine to punch holes in the chest diameter of the poplar tree, and then use 20% oxidized Leguo, methamidophos and other endosorbents 1 times the liquid, the dosage is 1 ml per centimeter chest diameter. This method has good insecticidal effect, safe, small side effects on natural enemies and the environment, and can also treat other stinging insect pests.
2.2.3 Biological control. Next-generation ovoid biological control is carried out at the same time as the drug prevention of larvae before 3 years of age. It is mainly controlled by releasing the egg parasitic bees of poplar boat moths such as red-eyed bees, pine caterpillar red-eyed bees, and black egg bees. Generally, it is released 1-2 times in the first generation of eggs, and 3 times during the initial stage of the second generation of eggs to the peak period. The amount of release is 30,000-50,000 heads per mu under the low insect population, and 50,000-100,000 heads per acre with high insect mouths, and the interval between each release of bees is 4-5 days. The proportion of each release is about 20% of the total amount of eggs released at the beginning of the occurrence, 70% of the total amount of eggs released during the peak period, and about 10% of the total amount of eggs released at the end of the egg period.
3 Stinging moths
3.1 Occurrence
The main species of thorn moths that harm poplar trees are yellow thorn moth, brown thorn moth, flat thorn moth and brown-edged green thorn moth. It is a common pest of a variety of broad-leaved trees and shrubs such as forest belts, street trees, garden trees and fruit trees. Its small larvae often feed in clusters, eating the epidermis and flesh of the leaves, leaving only the upper epidermis, and the food spots are round and transparent; With the increase of insect age, after 3 years, it begins to disperse and feed, endangering the whole leaf, leaving only the leaf veins and petioles, which has a great impact on the normal growth of the forest and the yield of fruits, and causes the tree to die when it is serious. Stinging moths have small pectoral feet and degenerated gastropods. The larvae have poisonous spines that touch the skin and cause redness, swelling and burning pain. Adults are thick and short, with scaly hairs on their wings and thicker; The larvae are short, thick, but have a smaller head and can shrink under the foreparticle.
3.2 Prevention and control measures
3.2.1 Eradication of overwintering cocoons. In order to effectively reduce the density of insect populations and prevent large-scale occurrences, it is necessary to collect insect cocoons by picking, tapping, digging and other methods according to the cocooning sites of different species of stinging moths, and dig pits to bury them.
3.2.2 Kill the first-infancy larvae. The small larvae of the stinging moth have the characteristic of clustering, and they will gather a lot on a single leaf, and they can be removed from the leaves and destroyed intensively.
3.2.3 Kill mature larvae. If the mature larvae want to enter the soil and cocoon, they must crawl slowly before entering the soil, and they can be inspected under the tree in the morning and killed when the larvae are found.
3.2.4 Lights booby trap adults. Most adult stinging moths have phototropism and can place black light lamps, and after the adults are feathered, they will see the lights flying to the light source in a concentrated manner, and then hunt them intensively.
3.2.5 Pharmaceutical control. The larvae of the stingray are weak in resistance to the agent, and can spray 80% dichlorvos emulsion or 90% crystalline dichlorvos 1000-1500 times liquid, 12.5% bromethrin emulsion or 20% permethrin 1500-2000 times liquid, and the effect is good.