About the author: Duan Xihan, senior agronomist of Liquan County Plant Protection Plant Inspection Station, has been engaged in disease and pest prediction in the front line for 37 years, and has accumulated rich practical experience, closely combining the phenology of fruit trees with the control of diseases and insect pests, using phenology to predict the time of disease and pest control, and the control methods are scientific, flexible and practical.
Peach tree mulberry white borer can also be called mulberry shield borer, peach shell worm, in the peach orchards everywhere, serious caused by tree weakness, branch death, serious whole plant death. Because fruit farmers do not grasp the law of its occurrence, they often miss the appropriate period of prevention and treatment, and the effectiveness of prevention and treatment is very poor. The method of phenological indication was used to predict the best time for mulberry white borer shell out, and effective comprehensive control measures were proposed in combination with prevention and control experiments and production practices, and good control results were achieved.
1. Adults
Female adult; wingless, broad, inverted pear-shaped, orange-yellow to orange-red, body length 1.10 to 1.30.mm, slightly pentagonal, broad circle at the front, triangular at the rear, the later thorax is the widest, abdomen 9 segments, segments are obvious. The lateral margin of each segment protrudes into a rounded lobe. The hips are broad, yellowish-brown or reddish-brown. The skin is membranous except for the buttocks, and the mouth needle is filamentous.
Male adult; winged, long, long spindle-shaped, orange to orange-red, body length 0.65 to 0.70 mm. Wingspan of about 1.32 mm, antennae candida-shaped, pale yellow, 10 knots. The length is almost equal to the length of the body. The forewings are membranous, transparent, off-white, with wing veins .2. bifurcated, the hindwings degenerate into a balance rod; the end of the abdomen has 3 pairs of sword-like tailparts that can fly.
2. Eggs
The eggs are oval in shape, pale pink for the first eggs, fade to a yellowish brownish brown, and are orange-red before hatching. The egg is about 0.25 mm long and about 0.12 mm wide.
3. Nymphs
The hatching nymphs are pale yellowish brown, oblate oval or oblong, about 0.30 mm in length, secrete woolly wool to cover the body, and after peeling, they begin to secrete waxy substances to form a mesembranous shell, and the peeling is covered on the shell, called the shell point. Nymphs hatched from white eggs, white, are males. The nymph hatched from the orange egg, which is orange, is a female.
4. Pupae
Pupae are all male pupae, oblong oval, orange-yellow, about 0.60 mm long, with purple-black eye spots.
5. Shell
Female shell; round slightly raised, 1.70 to 2.80 mm in diameter, molt is biased anteriorly, but not on the edges, the peritoneum is extremely thin, often left on the host plant, off-white or yellow-white. Generally immature adults are pale yellow. The two antennae are close to the center of the proximal end of the body, and are tumor-shaped, with a bristle on it. It has 15 valve glands, arranged in a half-moon shape.
Male shell; slender, about 1.00 mm, white. There are 3 longitudinal ridges on the back, and the shell points are yellowish brown or orange-yellow, located at the front of the shell.
Mulberry white beetles are infested by nymphs or adults parasitizing branches and stems, and sucking sap by needle-like mouthparts piercing into the cortex of the branches. In severe cases, the trunk and entire branches of the tree are covered with shells that overlap each other, creating a bumpy off-white waxy substance. As a result, the bark layer of the tree is sucked dry and shrunk, cutting off the delivery route of nutrients needed for the growth and development of the tree, resulting in poor development of the tree, obstruction of metabolism, wilting of branches, thin leaves, and even the death of the whole plant. After the occurrence of this insect in the peach orchard, if effective measures are not taken in time to prevent and control, generally 3 to 5 years, the entire peach orchard can be destroyed.
The degree of harm caused by mulberry white borers in peach trees of different ages is obviously different, mainly in peach trees of 10 to 15 years and 16 to 20 years old, and the degree of harm of other peach trees is 1 to 5 years, 6 to 10 years and more than 20 years, which shows that mulberry white borers are the least harmful to old peach trees. In the course of the investigation, it was found that the female shell was rarely seen on the trunk of the elderly almond tree, and it could only be found on individual branches, but it was not a piece of outbreak hazard. Mulberry white borers occur severely on robust peach trees in the peak of fruit hanging, and the area covered by female mulberry white beetles on individual trunks is up to 80%. Therefore, between different peach orchards, it is necessary to strengthen the prevention and control of mulberry white borers on healthy peach trees during the peak of fruit hanging to avoid disasters.
1. Climatic factors
In recent years, with the changes in the global climate environment, the climate has become relatively humid, and the rainfall has increased year by year, providing favorable climatic conditions for the breeding and reproduction of mulberry white ants. At the same time, the warm winter climate in these years is also conducive to the overwintering survival of mulberry whiteflies, which increases the base of pest damage every year.
2. The number of natural enemies has decreased sharply
Organophosphorus and pyrethroidic acid insecticides are widely used and frequently, and natural enemies are killed in large numbers. For example, the red-spotted lip ladybird, an important natural enemy of the mulberry white borer, is rarely found in the peach orchard. After the decline of natural enemy control ability, mulberry white pest rose from the original secondary pest to the main pest, and mulberry white beetle occurred in peach trees and showed an aggravating trend.
3. Do not pay attention to quarantine work
The long-distance transmission of the mulberry white beetle is mainly artificial. If the seedlings and scion are carefully inspected and sterilized during the construction and grafting, the cross-regional and cross-garden transmission of mulberry white borer will be effectively controlled.
4. Low degree of attention
Mulberry white borer body is small, not easy to find, the occurrence and spread of the spread is relatively slow, the beginning is only sporadic occurrence, gradually occurs in dots, generally four or five years all over the garden, and its harm is not as good as leaf eating and other pests are easy to find. Therefore, the fruit farmer neglected to control the mulberry white beetle, and it was too late to prevent and control it when the harm worsened.
5. The prevention and control method is inappropriate
In the years with changeable climate, the occurrence period changes every year, and some fruit farmers still manage according to the time of pest control and disease control in previous years, and do not use drugs during the critical period of prevention and control, resulting in large-scale occurrence.
6. Single use of pesticides
Because the fruit farmers do not have much knowledge of their occurrence rules and pesticide use, they cannot reasonably and scientifically grasp the peak period and comprehensive control of each generation of nymphs in the use of chemical pesticides, and blindly use several conventional insecticides for a long time and in large quantities, resulting in the formation of a strong resistance to several commonly used chemical pesticides, resulting in a large number and common occurrence.
Mulberry white borer occurs in Liquan County, Shaanxi Province, 2 generations a year, with the geographical location and climatic conditions of each year, the time of occurrence in each region varies every year, the first generation occurs about April to May, the second generation occurs in About July to August, and the second generation of fertilized female adults overwinters in clusters above 2 years old branches.
Overwintering mulberry white borer fertilized female insects generally fixed branches, rarely move, in mid-to-late March, peach tree buds germinate when the overwintering mulberry white borer fertilized female insects began to suck harm, the insect body rapidly expanded, in mid-April began to lay eggs, egg period 7 to 12 days, each female adult can lay eggs about 90 ~ 340 grains, mid-to-late April for the spawning peak, the first generation of eggs hatched after the nymph out of the shell of the peak period is generally in late April to early May, nymphs gradually crawl out from under the mother's shell, scattered crawl to the branches fixed feeding as a pest, 5 to 7 days (the best period for chemical control) the insects secrete white wax powder, and after the second peeling, they differentiate into the first generation of male adults, and the male adults begin to feather in early to mid-June, and the feathering is peak in mid-to-late June. The first generation of adult insects have female and male tails, and the males die after mating.
The first generation of female adults lay eggs in early to mid-July, mid-July is the peak of egg laying, the second generation of eggs hatch after the nymph shell peak in mid-to-late July to early August, nymphs stay under the mother shell for several hours after hatching and then gradually crawl out of the mother shell disperse activity for about a day, more than 2 to 5 years old on the branches of the fixed feeding, to the branch fork and the vulva density is larger. After about 5 to 7 days (the best period of chemical control), it begins to secrete a woolly white wax powder covering the body, gradually thickening, and soon it will peel off, and when it peels, it will split from the ventral surface, and the insect body will move backward slightly, and continue to secrete wax to cause a shell. Male nymphs are 2 years old, and the second peeling occurs in mid-to-late August, and the males begin to feather into second-generation adults. The end of August is the peak of feathering. The male dies after the female and male adults have crossed their tails, and the second-generation fertilized female adults continue to overwinter on the branches until late autumn.
The morning and evening of the peach tree mulberry white borer every year is determined according to the local temperature of the year and is variable. The control time of peach tree mulberry white borer also changes with the local temperature change in that year. Because, plants and pests that grow in the same environment, both after long-term adaptation, are hereditary. There is a direct biological and physiological connection between the appearance of mulberry white borer and a certain phenological phenomenon. Therefore, it is quite accurate to predict the peak period of nymph shell emergence of each generation of mulberry white borer by taking a certain phenological period of the plant as an indicator. The date of occurrence of various phenological phenomena, although it changes with climatic conditions every year, remains unchanged every year within the same microclimate. As long as you know that the former phenology came a few days earlier or a few days later in the current year, you can predict that the latter phenology will come a few days earlier or later that year. The time of prevention and control of mulberry white borer is predicted according to the time of shell emergence and the corresponding phenology.
Predicting the occurrence period of mulberry white worm with phenology is flexible. Phenological indicators are visible and tangible living indicators, it is very intuitive, the average farmer can grasp, easy to apply in practice. After years of practice, we have summed up a lot of experience in predicting the occurrence of mulberry white borers during phenological periods.
For example: indicates the phenology of the peak of each insect state of mulberry white borer; (the annual occurrence time is dynamic)
The overwintering female adults emerge from the stinging period; the iron-stemmed begonia spreads its leaves, and the first flowering period of the mountain peach is the peak period of the insect.
After the first generation of eggs hatch, the nymphs are in full bloom, and (late April to early May) the first flowering of persimmon trees (5%), the first flowers of neem trees (5%), the first flowers of pomegranate trees (5%), and the first flowers of catalpa trees (5%).
The first generation of male adults is in full bloom; the first flower of the dry locust tree, the peak of the Privet flower, and the peak of the hibiscus flower.
After the hatching of the second generation of eggs, the nymph shell is in full bloom; (mid-to-late July) the "Tomishima" variety begins to ripen, the first harvest of Ligala, the first flowering of mandala, and the beginning of the fall of locust trees.
The second generation of male adults is at its peak of feathering;(late August). Jujube ripening harvest, Qinwang peach ripening period.
To put it simply, when the persimmon tree falls 5% of the flowers, it is the best time for a generation of peach trees to spray.
Mulberry white borer occurs in peach orchards in our county, mainly in the peak of fruit-bearing healthy peach trees are seriously harmful, the number of insect mouths is large, and the elderly insects and adults have wax shell protection, missing if the insect hatching peak spray control, it is difficult to work. Therefore, in terms of prevention and control strategies, it is necessary to attach importance to the robust peach trees in the peak period of hanging fruit, and we should focus on clearing the garden in the spring, eliminating female adult insects after wintering, paying close attention to the chemical control of nymphs in the peak period after the hatching of eggs of the first generation, and paying attention to the protection and utilization of natural enemies of pests and giving play to the control role of natural natural enemies. After the hatching of each generation of eggs, the control of chemical pesticides is mainly used in the peak period of dispersed transfer of nymphs, and comprehensive control is carried out in combination with other measures.
1. Winter prevention and control
Do a good job of winter garden clearance, combined with pruning, pruning the affected branches, scraping the female adults who overwinter on the branches, and spraying a 3-degree stone sulfur compound of Bomé or 25% thiazideone wp1500 times liquid double liquid, eliminating the source of wintering insects and reducing the harm in the following year.
2. Biological control
The natural enemies of mulberry white aphids mainly include red-spotted lip ladybirds, black-edged red ladybirds, heterochromatic ladybirds, deep-spotted mite ladybirds, Japanese square-headed beetles, soft aphid wasps and lily grasshoppers, etc., which can artificially create conditions conducive to the growth, reproduction, growth and development of natural enemy insects, in order to inhibit the occurrence and harm of peach garden mulberry white nymphs, and avoid spraying broad-spectrum pesticides.
3. Chemical control
In early spring, peach trees are sprayed with 1 5-degree stone sulfur compound or 0.2% clay diesel emulsion, or 2 times sprayed with 50x lime water (about 5 days apart) to eliminate overwintering female adults.
According to the peak period of nymph shell emergence and corresponding phenological indicators after the hatching of eggs of mulberry white borer, it is possible to master the spraying of chemical pesticides before the dispersion and transfer of nymphs in each generation, the secretion of wax powder, and the formation of a messe shell can achieve the effect of doubling the results with half the effort.
Agent options: Choose from 48% Lesben 1500x liquid, or 48% Chlorpyrifos 1500x liquid + penetrant (0.1% laundry detergent liquid), or 10% cypermethrin 2000x liquid, or 25% Kung Fu Water Agent 2000x liquid. or 20% sauere 2000 times liquid, or 22.4% spironium ethyl ester suspension 2500 times liquid, or 52. 25% toxic chlorine emulsion (agrodi) 1000 to 2000 times liquid, or 10% imidacloprid wettable powder 1500 times liquid, or 2000 times liquid of pyridoxine No. 3, or wax borage 800 to 1500 times, or 25% thiazinone wp1500 times liquid and other spray control. When spraying, the focus is on the forks of the branches where the mulberry white borer overlaps and the shady side of the spray. Insecticides should be applied alternately, and each incubation period (nymph dispersion transfer period) is a critical period for drug control. Spray the drug 2 to 3 times in a row, and add 200 to 300 times neutral laundry detergent during the growing season to improve the prevention and control effect. It can effectively prevent the spread of mulberry white borer.