The pear psyllid began to sting during the flower bud expansion period of pear trees, reached the peak stage of stinging in mid-March, and gradually declined thereafter. The first generation of pear psyllid adults begin to damage the new shoots of pear leaves from late April to early May.
The sap of the pear tree is sucked and the tail is laid eggs, and the life span is only 20~30 days. Adult pear psyllids are more active during the high temperature period during the day, and like to hide in the pear leaf dorsal petioles, as well as tender shoots and other pear growth and development parts, and can fly short distances when disturbed.
Picture 01~02): Damage of pear psyllids on leaves
The eggs are laid in the crevices of the buds of the leaves of the short fruit branches of the pear, or between the hairs of the young tissues of the pear leaves, in the groove of the main vein on the front of the leaf or between the serrations of the leaf margin. The peak flowering period of pears is the peak period for laying eggs (the first generation of adults). Then the nymphs after hatching will swarm and damage the new shoots of the leaves of the pear tree, and the generations overlap. If it is not controlled in time, it will aggravate the damage to pear trees.
In this issue, Qingjiang Crane will focus on and chat with all the teachers about the hazards of pear wood wind. The purpose is to find effective methods for the prevention and control of pear psyllids by identifying the harmful symptoms and exploring the occurrence rules of pear psyllids in the field, so as to improve the comprehensive prevention and control effect of pear psyllids and ensure the planting benefits of pear fruits.
Image 03~04): Appearance and morphology of pear psyllid
Overview of the hazard characteristics of pear psyllids in the field:
Pear psyllids are an important pest that pear trees often encounter during their growth and development, and they harm the branches, leaves and fruits of pear trees with their unique "stinging and sucking mouthparts". It has caused serious harm to the growth and development of pear trees and fruit quality, reduced the commercial value and edible value of pear fruits, and reduced the planting benefits of fruit farmers.
The adults of the pear psyllid are divided into winter and summer types, with the winter type adults having brown to dark brown body color with black-brown markings, while the summer type adults are slightly smaller, yellow-green in color, and have no markings on the wings.
The nymphs of the pear psyllid are oblate-oval, pale yellow or milky white when first hatched, and then gradually turn light green, and the large amount of mucus they secrete will not only make the leaves sticky, but also pollute the fruit, which greatly affects the yield and quality of pears.
Picture 05~06): Pear psyllids mixed with aphids
Under the bite of the pear psyllid, the leaf veins will be distorted, the leaf surface will shrink and lose green, and brown wilt will gradually appear. Over time, these leaves gradually darken and eventually shed their main branches prematurely.
For fruits, the mucus contamination of pear psyllids will lead to moldy stains on the fruit surface, which seriously damages the appearance of the fruit and reduces the commercial value and edible value of the fruit.
The nymphs of pear psyllids can also cause harm to new shoots, especially the lignified branches of 1~3 years, which often cause "wounded flow" or dead branches, affecting the formation and extension of the canopy.
Exploration of the harm law of pear psyllid in the field:
Picture 07~08): Pear psyllid mixed with aphids
The harm of pear psyllid in the field is closely related to its living habits. In general, the first generation of adults of the pear psylle begins to emerge in early May, and then undergoes multiple reproductive "stacks" until the "end" of autumn. 4~6 generations occur per year.
Due to the uneven development period between generations, there is often overlapping damage of pear psyllids in the field, which makes the control work more complex and arduous.
In spring, after the adults and nymphs "emerge" in March, they mostly concentrate on the new shoots and petioles of pear trees. In summer and autumn, they mostly "swarm" on the back of the leaves to suck their sap. Very little activity and slow crawling. Mature nymphs mostly crawl near the edge of the pear leaf or the tip of the leaf to "peel" and emerge, and enter the "hibernation" recuperation period.
Picture 09~10): Pear psyllids and aphids on the back of leaves
This kind of damage makes pear trees face the threat of pear psyllids throughout the growing season, and it is necessary for fruit farmers to carry out "nanny-style" continuous monitoring and timely and accurate prevention and control.
Effective measures for effective prevention and control of pear psyllid:
According to the hazard characteristics and field hazard rules of pear psyllid, we can adopt the following effective prevention and control strategies:
01) Prevention and control of pear psyllids in field agriculture:
By strengthening the management of pear orchard fruit trees, especially in winter, cleaning the garden, scraping off all the old bark with insect eggs, cleaning up the residual branches and fallen leaves and other parts that are easy to "hide insects and eggs", as much as possible to destroy the various wintering places of pear psyllid, reduce the source of overwintering insects, and reduce the damage base of pear psyllid. At the same time, reasonable fertilization and irrigation can enhance the vigor of pear trees and improve the resistance of pear trees to pear psyllids in the growing season.
Picture 11~12): Pear psylle on leaves
This is the basis for doing a good job in the winter management season of pear trees and the damage of pear psyllids in the early stage of pear trees, which is not only a key link, but also an indispensable prevention and control measure.
The second is that when watering the pear orchard with "winter irrigation", you can "irrigate" some pear psyllids that are wintering in the cracks of the loam.
02) Physical prevention and control of pear psyllids in the field:
Biological control is carried out by using the natural enemy of pear psyllid (psyllid jumping wasp), such as protecting and releasing the natural enemy insect of pear psyllid (about 40 per tree) and other physical means for control. This kind of prevention and control method may be impractical and unreliable for ordinary fruit farmers. Maybe it's just a demonstration stage. However, with the improvement of scientific and technological content and the advancement of agricultural technology, perhaps this technology of releasing the natural enemy of pear psyllid, "jumping wasps", will be applied to production.
Picture 13~14): Pear psyllids and aphids
03) Chemical prevention and control methods for pear psyllids in the field:
In the peak stage of adult sting (the peak stage of adult stinging of P. psyllids is mid-March) and the peak stage of nymph hatching (the first bud stage of pear buds), and the top leaf curling stage of pear shoots, select appropriate pesticides for spraying and control.
The common agents and concentrations that can be used for the prevention and control of pear psyllids are: 30% spirometallethyl ester dinotefuran suspension 3000~3500 times liquid, 8% cyhalothrin clothianidin suspension 1500~2000 times liquid, 5% avermectin imidacloprid emulsifiable concentrate 1000~1200 times liquid, 10% avermectin acetamiprid water dispersible granule 3000~3500 times liquid spray, 22% halodioxapyr suspension 4000~6000 times liquid spray, 50% 10000~12000 times of sulfoxapyr water-dispersible granules, or 4000~5000 times of 30% spiromethane ethyl ester suspension, 5000 times of 40% spiroxazil ethyl ester suspension, 2000~2500 times of 30% pymetrozine wettable powder, 3000~4000 times of 50% pymetrozine water-dispersible granules, or 1500~2000 times of 5% acetamiprid emulsifiable concentrate can be sprayed on stems and leaves.
Picture 15~16): Pear psyllids and aphids on fruit branches
The selection of pesticides should take into account the impact on the environment and natural enemies, and try to use low-toxicity, high-efficiency and environmentally friendly pesticides. At the same time, pay attention to the spraying should be uniform and thoughtful to ensure that the front and back sides of the leaves can be in contact with the agent.
Words written at the end of the pear psylloid prevention and control in the pear tree:
In summary, pear psyllids have brought serious harm to pear tree production due to their unique damage characteristics and field damage rules.
In order to effectively prevent and control the harm of pear psyllid, we need to adopt a comprehensive control strategy, including agricultural, physical and chemical control. Only in this way can we ensure the healthy growth of pear trees and improve the yield and quality of pears.
Picture 17~18): Expansion period of young pear fruits