The walnut lifting moth is one of the main pests that endanger the healthy growth of walnut trees. The walnut lifting moth specializes in eating the green skin of the fruit of walnuts, and the victim fruit becomes black and shrinks, losing its economic value, so it is called walnut black. Some of the larvae burrow into the heart of the fruit early, deep into the kernel, causing the kernel to dry up, which has a great impact on walnut yield. In severe years, the rate of black fruit can reach more than 80%, and walnuts are almost out of fruit. Mastering the pollution-free control technology of walnut lifting moth can not only better control walnut lifting moth, but also reduce environmental pollution. I hope that this article can give some help to the vast number of people engaged in pest control and disease control and farmers and friends.
First, the harmful symptoms of walnut lifting moths
After the hatching larvae stay on the fruit surface for a period of time, they begin to crawl in search of the fruit. The time of the borer fruit is 5 to 8 hours, and after the larvae are mothed, a colorless gelatinous secretion appears at the borer hole, which later becomes a transparent white bead and gradually becomes amber. After the larvae are eaten in a vertical and horizontal string in the green skin, the initial pest stage, the borer holes are linear, deep to the kernel, so that the peel is dried and shrunk black, so it is also called "walnut black". The tunnel of the borer hole is full of insect dung, and the larvae in 1 fruit can reach several heads, and more than 30 heads, and the victims are black and rotten. Early fruit, walnut kernel stunted, peel shrinkage and blackening, early shedding, but the larvae do not turn into pests. Some larvae eat fruit stalks, causing early fruit fall. Old ripe larvae generally begin to shed fruit in mid-to-late August, when the green skin of the affected walnut turns black and the flesh deteriorates and rots. When the old ripe larvae shed fruit, they first bite through the peel and fall to the ground, crawl on the ground to find a suitable place to enter the soil and cocoon for wintering, and the fruit removal period is about 1 month.
Second, the cause of serious harm to the walnut lifting moth
Due to the lack of attention to pest control in walnut planting and production, walnut lifting moths occur in large quantities. The insect is the most serious pest in walnut production, with larvae moths into the hard shell to eat seed kernels, the early harm is not obvious, it is not easy to find, once the fruit is found or the fruit turns black, often has missed the control time, seriously affecting the yield and quality of walnuts.
1. In recent years, the temperature in winter is warm, and the rainfall in June and July is more. The rainy and wet years of the adult feathering period occur heavily, and the dry years are lighter.
2. The planting environment is not good. Where the soil moisture is large and overgrown, it must be heavy; the general nest wind and wet places and deep mountainous areas occur heavily, and the sheltered and sunny dry places and shallow mountainous areas occur lightly; the shady slopes are heavier than the yang slopes and ditches; and the barren slopes occur heavier than the frequently cultivated land.
3. Insufficient attention, management can not keep up, extensive management. There is not enough water and fertilizer. Pruning is not timely.
4. Due to the low quality of farmers' pest control and control, the prediction of the appropriate period of prevention and control is not accurate, or even predicted, and the best control period is missed; the wrong medicine is used to prevent and control according to the disease.
Third, walnut limb moth pollution-free control technology
It is necessary to fully implement the principle of "prevention first, scientific governance, supervision according to law, and strengthening responsibility", so as to give priority to the use of pollution-free prevention and control technology, prescribe the right medicine, use drugs in a timely manner, and rotate drugs. Each pollution-free chemical pesticide is used up to once a year, and the interval between application and harvesting should be more than 30 days.
Cultivation measures. Measures such as timely watering, increasing the application of farm manure, pruning, and timely removal of male flowers are taken to ensure that the tree is strong and healthy. Before winter, coat the trunk with 10 parts of quicklime, add 1 part of sulfur and 40 parts of water to protect the tree and prevent pests from overwintering on the trunk. Spray stone sulfur compound before budding.
Deep tip tree tray. According to the characteristics of the old mature larvae of the walnut lifting moth mainly concentrated in the soil layer around the trunk, the late autumn or early spring deeply overturns the soil under the canopy, destroying the overwintering cocoon, and the overwintering cocoon can be turned to the ground, so that it freezes to death or is eaten by birds. Partially overwintering larvae are destroyed, or adults cannot be unearthed after feathering. The depth of ploughing should reach more than 20 centimeters. The walnut tree trays on the hillside should be planed into fish scale pits. At the same time as the planing plate, the insect cocoons in the soil are picked up and destroyed in a concentrated manner.
Clean the orchard for hygiene. Eliminate the source of overwintering insects. Walnut lifting moth overwinters with old mature larvae in the shallow soil layer under the canopy and in deciduous weeds, so it is necessary to remove dead branches and weeds in the garden in time to effectively reduce the occurrence of pests.
During the growth period, the insect fruits are collected in the garden and destroyed in a concentrated manner. During the growing season, before the larvae are defruited, the damaged fruits under the walnut trees are picked up and buried and destroyed in time. Picking black fruit for more than 2 consecutive years, the prevention and control effect is more than 85%, this method is simple and easy to implement and cost-effective.
Biocontrol. Vigorously promote the system of raw grass farming, protect and utilize natural enemies, enrich the insect population in orchards, and use natural enemies to suppress the number of pest populations. From mid-June to adult feathering, until the end of feathering, a trap made of sexual attractants is used to hang on the tree, trapping males and reducing adult mating and laying eggs. From June to July, the natural enemy red-eyed wasp is released, releasing 300,000 heads per acre, which can reduce the density of the insect population of the pest and effectively inhibit the harm of the walnut lifting moth. Use of microorganisms to control walnut lifting moths. In the adult feathering period of 4 to 7 days, the larvae sprayed Witheria thunii before hatching the borer fruit, with a concentration of 200 million spores/ml, and the control effect was remarkable.
Sprinkle medicine on the ground. Before adult feathering or when individual adults begin to feather, the larval urea is applied under the canopy during the defruiting stage of the larval, and good results can be obtained by poisoning the larvae. Before adult insects feather, 1000-2000 times 1.8% avermectin emulsion can also be sprayed on the ground around the trunk, and 0.5 kg per acre can be used to poison the native adult insects. Note that when applying avermectin for control, a shallow hoe should be carried out to make the pesticide and the soil fully mixed evenly to achieve the purpose of long-term touch killing, thereby prolonging the efficacy period.
Spray medicine on trees. The walnut lifter moth is a borer pest that has the longest larval stage in its entire life cycle, but only exposes the larvae for a few hours at the time of hatching and crawls in small areas in hidden places. Feeding moths are mostly found in calyxes and stalk depressions between the two fruits, and eggs are also mostly produced in covered places, such as calyx clusters. Therefore, the effect of killing larvae by drug touch and stomach poison is poor. The adult limb moth has poor flight ability, small range of activity, 2-3 days in the early stage of egg laying, most of the lower leaves in the canopy of the front and back of the fall and crosstail, looking for spawning places also need to contact the fruit surface crawling, so there are more opportunities for touch killing. It is mastered during the peak stage of adult feathering and egg laying and the initial incubation period of larvae from mid-June to mid-July, with an interval of 10-15 days between each spray. Canopy spraying was made of 25% urea No. 3 suspension 1500 times liquid and 1% matrine 1000 times liquid. Note that spraying should be before 10:00 or after 16:00, if spraying within 6 hours of rain should be timely re-spraying. The spray was carried out in three tree sprays, the first june 10-15, the second June 25-30, and the third July 10-July 15. Killing eggs and hatching larvae and killing the larvae before the borers work well. When spraying, it should be done without leakage and heavy spraying, and the medicine should be sprayed to the back of the leaves as much as possible. For closed walnut forests, during the adult stage, the adult insects can be smoked by smoke spraying, and the agent is matrine: diesel = 1:4. Insect pathogenic virus and polyhedral virus (DCPV) can also be sprayed, and people often use DCPV, BT, and white zombie bacteria for mixing to obtain a more ideal control effect.
Remove the victim fruit. From mid-July to early August, after the larvae have fallen fruit and before the old ripe larvae have shed fruit, the blackened infested fruit is picked in advance to eliminate the larvae that were harmful in the year and reduce the density of the next generation of insect populations. In mid-to-late July, the fruit fall is in full bloom, and the fruit is collected in time, burned or buried deeply in the soil, and the source of overwintering insects is eliminated.
Physical control. Due to the strong phototropism habits of adult insects, black light can be hung in the park to trap adult insects from June to August, and 1 insecticidal lamp can be hung every hectare or 50 meters away.
Source: New Technology of Fruit Tree Planting, Shanxi Science and Technology News
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