Key points of management of flowering period of pear trees with flowers

It is easy to cause the phenomenon of full flower and half fruit, low fruit setting rate and low economic benefit if the flowering period of pear tree is not properly managed or ignored. The following management methods are adopted in the flowering period of pear trees, which can improve the fruit setting rate, pear quality and economic benefits.

Artificial pollination of pear trees

First, topdressing before flowering: topdressing before flowering can improve the quality of flower buds, meet the nutrition consumed by flowering, and increase the rate of fruit setting. The available fertilizer, which is mainly compound fertilizer, is applied half a month before flowering. Generally, 0.5-1 kg per adult pear tree. If the tree is weak, 1-2 kg urea can be added, and the amount of fertilizer applied accounts for 10-15% of the total amount of the whole year.

Second, pre-flowering re-pruning: re-pruning pear trees that are too light and retain a large amount of flowers, remove thin and weak branches, diseased and withered branches, over-dense branches, adjust the load of pear trees, and determine the amount of flowers retained according to the amount of fruit retained. Generally, the amount of flowers retained is 1-2 times more than the amount of fruit retained, leaving only one flower bud per fruit table, eliminating too many flower buds, and a string of flower buds formed by growing branches of pear trees that are not sensitive to pruning should be cut short properly. Make the fruiting branch close to the trunk and promote the formation of long branches in preparation for future fruit.

Third, flower thinning and artificial pollination: pear flower buds are compound buds with as many as 5-8 flowers per inflorescence. Flowering consumes a lot of nutrients of pear trees and removes redundant flowers, which can concentrate nutrition supply and increase fruit setting rate. Flower thinning standard: large fruit leaves one inflorescence every 25cm, generally one inflorescence per 20cm; if the tree is weak, the remaining fruit should be thinner. The problems that should be paid attention to in sparse flowers: first, sparse small flowers, central flowers, improper flowers, keep edge flowers, because edge flowers bloom first, the fruit quality is good; second, when the number of flowers is uneven, strong branches stay more, thin and weak less; third, there are more in the middle and rear of the backbone branches and less in the front.

Pear pollination was effective within 7 days after flowering, and it was suitable for pollination within 3 days. Pollination can be done from 8 am to 4 pm, and the suitable time varies according to the climate of flowering stage. When the air temperature is lower than 10 ℃, the pollination effect is poor. When the flowering temperature is low, it should be carried out when the temperature rises to more than 12 ℃ around noon. In case of high temperature, the highest daily temperature is about 30 ℃, it should be pollinated in the morning or evening, otherwise the stigma will be scorched and have no effect. The suitable temperature for pollination is 15 ℃ and 20 min. When the flowering climate is bad, it is best to pollinate twice.

Fourth, spraying boron to promote fruit setting: boron can promote the germination and elongation of pollen tube and promote the transport of sugar in pear trees. Spraying boron at flowering stage can increase the fruit setting rate of pear trees. 0.3-0.5% borax (acid) solution can be sprayed once when blooming 25% and 75% respectively. Add 0.3-0.5% urea, a large amount of phosphorus and potassium are needed for flowering, and 0.3% potassium dihydrogen phosphate solution is added or sprayed alone to increase the fruit setting rate.

Fifth, anti-frost during the flowering period: pear trees bloom early, mostly before late frost, and are vulnerable to late frost. After pear flowers are frozen, the pistil turns brown, dry shrinks, blossoms but cannot bear fruit, and frost prevention measures:

1) pre-flowering irrigation, reducing soil temperature, delaying root activity, delaying flowering, reducing or avoiding late frost damage; 2) White trunk, white trunk before flowering, slow rise of tree temperature can delay flowering by 3-5 days, avoid or reduce frost harm. 3) smoke and frost prevention, smoking can reduce the radiation emission of soil heat and have the effect of moisturizing, at the same time, smoke particles can absorb moisture, make water vapor condense into liquid and release heat, increase ground temperature, reduce or avoid frost damage. Pay attention to the changes in the weather during flowering. Prevent frost when the temperature may drop to-2 ℃. Commonly used smoking materials: sawdust, straw, firewood, leaves, etc., layered staggered stacked, inserted in the middle of the ignition to facilitate the ignition of smoke. Before smoking, organize manpower, divide into pieces and be on duty, hang a thermometer at 1m from the ground, and record the temperature regularly. If the temperature suddenly drops to 0 ℃ in the early morning, you should light the smoke. When igniting, you should unify the orders and carry out at the same time, prevent the flames from burning, make them emit thick smoke as far as possible, and do not burn the branches of the trees. Antifrost fogging agent can also be used to prevent frost. The commonly used formula is ammonium nitrate 20-30%, sawdust 50-60%, waste diesel oil 10%, fine pulverized coal 10%, ammonium nitrate, sawdust and pulverized coal as fine as possible. After being proportioned, it is put into an iron barrel and ignited when used. 2-2.5 kg per mu, put in the upper wind.

6. pest control: pear trees before and after flowering are the key periods for the control of major pear diseases and insect pests (such as pear wood lice, yellow powder insect, pear fruit wasp, black spot). The main measures are as follows:

The main results are as follows: 1) pre-flowering is the key period for the control of pear wasps and planthopper adults, spraying enemy killing 2000 times or high chlorine 2000 times, and controlling yellow pink insects at the same time, adding Bio 2000 times + Rippel 5000 times to alleviate freezing injury and prevent the harm of cold in spring. 2) when the pear tree falls 80% of its flowers, it begins to spray. This is the key medicine. Be sure to spray it well. Indications: pear planthopper, Tenebrio Molitor, mites, black spot disease and so on. For example, the formula is as follows: Muwang 5000 times + auxiliary I + auxiliary II+ Antaisheng 800times + Jiayuan potassium dihydrogen phosphate 1000 times. In addition, new shoots damaged by diseased buds and pear stem bees should be cut off at any time.