Hazard symptoms and prevention measures of pear lice
Ningling County is located in the Eastern Henan Plain, belonging to the Yellow River Gudao area, built with 10,000 acres of pear garden, for the "Hometown of China's Crispy Pears".
In Ningling, the occurrence of serious pear garden hazard rate is more than 80%, and it has now become the number one pest of pear garden.
1 Hazard symptoms
Pear lice mainly harm pear trees, causing the leaves to dry up and fall off. Pear lice adults and nymphs can be harmful, mostly concentrated in the spring on the new shoots, petiole hazards, summer and autumn more in the leaf back to feed. Adults and nymphs suck up the sap of buds, leaves and young shoots, and nymphs secrete a large amount of honey mucus on the leaves, which often binds adjacent leaves together, and the stained leaves appear brown spots, causing early defoliation in severe cases, affecting yield and fruit quality. New shoots are affected, stunted, atrophy. Pear lice occur lightly in rainy years and heavy in dry years.
2 Occurrence
Pear lice belong to the order Homoptera and the family Pyllidaceae. Pear lice occur in 5 generations per year in eastern Henan, and winter-type adults overwinter in the gaps in the bark of the host tree, in the deciduous leaves, weeds and soil crevices. The following year, the stings emerge before and after the sting, and the eggs are laid at the tail (figure 1), and each adult worm can lay 100 to 140 eggs (figure 2).
Fig. 1 Overwintering adults cross tails
Fig. 2 Spawning site of overwintering adults (branches, base of fruit table)
The first generation lays eggs at the base of the bud, and the incubation period is in early April, with nymphs in full bloom in mid- and late-April.
The second generation occurs in mid- and late May to mid-to-late June, during the second generation of spawning before and after the wheat harvest, where the spawning site is on the petioles of several leaves in the upper part of the new shoots.
The third generation occurs from mid-June to early to mid-August, and the spawning site is between the serrations of the leaves, and from the third generation onwards, the generations overlap and chaos. Generation 4 occurs from early August to late August.
Generation 5 occurs in early September, with adults transitioning to overwintering from late September to October, and temperatures above 0 °C in the early spring of the following year.
3 Prevention and control techniques
3.1 Prevention and control period
There are two important periods of the year for the control of pear lice.
3.1.1 When a large number of adult adults of pear lice are stung in large numbers, that is, before and after the annual sting, find a high temperature and sunny weather to apply medicine to prevent pear lice, at this time the prevention and control plays a multiplier effect with half the effort, saving time, saving trouble, and the effect is good, which is the most important prevention and control period of the year.
3.1.2 The second generation of pear lice is the rampant occurrence period of pear lice before and after the wheat harvest, which is the second important period for the control of pear lice throughout the year, mainly to suppress the insect population base of pear lice.
3.2 Prevention and control methods
3.2.1 Agricultural control During the wintering period, cleaning up the dead branches and leaves and weeds in the garden, burning them in a concentrated manner, and scraping off the bark of the old warp tree in early spring can reduce the source of insects in pear lice.
3.2.2 Protection and utilization of natural enemies The natural enemies of pear lice are flower bugs, grasshoppers, parasitic wasps and predatory mites, ladybirds, thrips, etc.
3.2.3 Strengthen early drug control During the peak period of overwintering adults, that is, the early stage of the emergence of first-generation eggs, most of the overwintering adults have not yet laid eggs, and adults are exposed to branches, which is the best time for spray control. After the first spray, another spray every 10 days or so can basically control the hazard.
Before germination, 5 Baumedo stone sulfur compound can be used to spray the ground, trunk, branches carefully, comprehensively and evenly, rain spray. Spray the pesticide once every 10 days with a choice of 2.0% (mass fraction, same after) avermectin microcapsulation 2 000 times solution + 2.5% cypermethrin emulsion 1 500 times liquid. At about 80% of the flowers, use 22.4% spironium ethyl ester suspension 4 000 times liquid + 25% imidacloprid wettable powder 2 000 times liquid. The effect of using 22.4% spironoid ethyl ester suspension 4 000 times + 2.0% avermectin microcapsules suspension 2 000 times before and after wheat harvest is very good.
In addition to conventional chemical control, it can be mixed with agricultural silicone 3 000 ~ 5 000 times liquid spray, remove the mucus on the nymph for control, the effect is better.