Eight common problems affecting the appearance quality of bagged emerald pear and their solutions

Emerald is a new pear variety bred by Zhengzhou Fruit Tree Research Institute. It is a hybrid between the new century and Zaocu. In the past six years of bagging cultivation through high grafting head in 2000, it has been found that this variety is an early-maturing pear variety with good quality because of its positive fruit shape, smooth fruit surface, milky white pulp, crisp, juicy and few stone cells. However, in the production of bagged pears, it is often found that there are some abnormal phenomena affecting the appearance and quality of fruit, such as black wrinkle, fruit peel, tiger skin, green fruit face, black spots, cracks, deformities and so on. For this reason, we have carried out investigation and analysis, and put forward the method of solving force.

1. Problems that arise

A tiny longitudinal crack on the surface of a fruit that blackens, making the fruit surface rough and black. The reason is that fruit noodles, close to paper bags, potions or Rain Water are often soaked here, and the temperature and humidity change suddenly after sunny days, which stimulate the fruit surface and cause protective reactions and even damage to epidermal cells.

The fruit spot is large, the fruit surface is rough, and the fruit spot becomes larger, rough and dull in the whole or local fruit surface. The time of bagging is too late, and the drug damage in the young fruit stage before bagging is the main reason for large fruit spots and rough fruit surface.

A light green mark with flaky, striped, or indistinct edges on the surface of a fruit. The main reason is that the quality of the fruit bag is poor, the size is small, and the mouth of the bag is not tied strictly when bagging, and there is light transmission.

Fruit stalks generally appear more in the lower part of the fruit. The causes of ① bagging are too many times of spraying before bagging, miscellaneous varieties, and fruit stimulation; ② bagging is carried out when there is dew on the fruit surface or the liquid is not dry after spraying, which makes the calyx depression store water for a long time; ③ orchards are closed, and the middle and lower parts of the tree and inner fruits are affected by high temperature and humidity microclimate, forming water closures.

Irregular brown light brown spots on the surface of tiger skin. Before bagging, the young fruit is caused by branch and leaf friction and artificial mechanical injury.

A black or dark brown, sunken, or raised black spot or spot on the face of a fruit. It is mainly caused by drug damage and diseases and insect pests. Diseases and insect pests include scab, black spot, black spot, pear planthopper, yellow pink and so on.

Fruit cracking mainly occurs in the fruit expansion period, usually from mid-late June to fruit ripening. During the period of fruit expansion, drought, heavy rain or watering, less fruit and unbalanced nutrition are the main causes of fruit cracking.

Abnormal fruit includes crooked fruit, gully pear, pimple pear and so on. Poor pollination and fertilization, lack of boron and pests are the main causes of deformed fruit. Diseases and insect pests include scab, stink bug, Kang's pink scale and so on.

two。 The solution

Strengthen comprehensive management, enhance tree resistance ① re-application of organic fertilizer, increase compound fertilizer, prevent the extensive use of chemical fertilizer, and increase the content of effective nutrition of the tree; reasonable supplement of trace elements, while applying basic fertilizer in autumn, combined with trace elements such as borax and calcium superphosphate; timely foliar spraying fertilizer can spray 0.3% 0.4% borax aqueous solution at flowering stage for pear orchards caused by boron deficiency. In addition, before bagging, combined with spraying 2 or 3 times of high-quality calcium fertilizer, such as amino acid calcium, Ryan calcium, Cuikang calcium, etc., to reduce fruit cracking and physiological diseases caused by calcium deficiency. ② irrigation in the dry season and timely drainage in the rainy season make the soil keep a certain water content and avoid the sudden change of soil moisture. ③ orchard covered with grass or grass under trees to change the microclimate environment. Reasonable pruning of ④ can improve the ventilation and light transmission condition of tree rest. Advocate grid cultivation, so that the fruit is evenly distributed under the grid, reducing the damage to the fruit surface caused by the leaf sweeping. During the establishment of ⑤ garden, pollination trees were arranged rationally, mixed pollens of Yali pear, Yuanhuang and Huangguan were selected for artificial pollination, flowers and fruits were thinned strictly, one of the 2nd, 3rd and 4th order of inflorescence was selected, and the amount of fruit left in 667m2 was kept at 12000 ~ 13000.

Before bagging, high-efficient and high-quality insecticides must be sprayed once or twice before bagging, and attention should be paid to ① choosing agents that are safe to the fruit surface, such as methyl thiophanate, carbendazim, carbendazim, imidacloprid and so on. Pay attention to the selection of powder and water agent, avoid the use of EC agents. There should be no more than 3 kinds of spray at a time, the concentration should not be too high, and the dispensing water should not use well water with high hardness and polluted river water. ②, pay attention to the spraying time. Spray after 7-10:00 or 4 p.m. ③ improves the quality of spray. The spray head should not be too close to the fruit and stay for too long, the droplets should be small and constantly stir the liquid, and the amount of spray should reach the dense fog drops of pear fruit.

Select high-quality fruit bags and standardize bagging technology

Emerald had better choose outer flower (wood pulp paper) inside black double-layer bag or outer flower black inside is cotton paper 3-layer bag, the inner layer of black paper should be more than 45g, cotton paper should be soft, in order to prevent bruising young skin. Bagging usually starts with the fixed fruit and is completed before the middle of May, sooner rather than later. Bagging time should be chosen from 8 a.m. to 11:00 and 2: 6 p.m., not under the conditions of high temperature, dryness and humidity, and it is strictly forbidden to bag when there is dew on the fruit surface and when the medicine is not dry. When bagging, the bag should be expanded, the pear fruit should be in the middle of the bag, not attached to the pear bag, and the mouth of the bag should be tightly fastened. In the process of bagging, you should be careful not to scratch or prick the fruit noodles.

On the basis of agricultural control, ① can reduce the source of overwintering diseases and insect pests by clearing garden in winter and spring, cutting off branches of diseases and insect pests, turning over tree plates, pouring frozen water, whitening tree trunks, scraping rough bark, warping skin and disease spots, etc. In the growing season, the source of re-infection was controlled by cutting off diseased shoots, diseased leaves and diseased fruits. ② advocates biological control, protecting or artificially stocking predatory natural enemies in orchards, such as grass ridges, ladybugs, flower bugs and so on. The chemical control of ③ should be carried out on the basis of good prediction and control in the key period. The prevention and treatment is as follows: spraying Baume 3-5 degree stone sulfur mixture during the flower bud expansion period. When petals fall off 70%, 1.8% avermectin 5000 times + pyrethrin 2000 times + 70% methyl topiramate 1000 times + 80% ethyl aluminum 800 times are sprayed to control pear planthopper, black spot, scab, black spot and so on. Before bagging in the first and middle of May, 10% imidacloprid 3000 times + pyrethrin 2000 times + 80% carbendazim 1000 times were sprayed to control yellow powder insect, green bug bug, black spot disease and so on. After the rain in May, it was sprayed to control green bug, yellow powder bug, Kang's pink scale, black spot and so on by spraying 2000 times of broom and 1000 times of polyactinol. Spray 1.8% avermectin 5000 times + 80% must gain 1000 times + 48% Lesbon 2000 times + 1000 times before wheat harvest in early June. Spraying 10% imidacloprid 3000 times + mancozeb 1200 times + killing 1000 times during the fruit expansion period in mid-late June. During the period of rapid fruit expansion in the first and middle of July, spraying 48% Lexben 1500 times + 15% dicarboxylic acid 3000 times + 80% must gain 1000 times + 1000 times to assist in killing. During the fruit harvest period, permethrin was sprayed 2000 times + 20% triadimefon 2000 times to control yellow powder insect, Kang's pink scale and so on. When spraying, pay attention to spray fine, spray evenly, spray strictly, so that neither leakage nor re-spraying, not only improve the effect of prevention and control, but also prevent drug damage.