When does the pear tree in Changzhi, Shanxi germinate?

The germination time depends on the local climate. The Changzhi area in Shanxi is about half a month before Tomb-Sweeping Day, where flowers bloom first and then leaves grow.

phenophase

Pear trees are widely distributed, so their phenological periods are very different. As far as flowering period is concerned, Huili and pear trees in Sichuan generally bloom in the first half of February, and Yanbian in Jilin blooms in mid-May. Yali pear bloomed in Changsha, Hunan Province in early March and in Beizhen, Liaoning Province in early May, with a difference of nearly two months. Pear trees cultivated in the same area have different phenological periods due to different species and varieties. From germination to flowering, pear is the earliest, pear is a little later, sand pear is later than pear, and western pear is the latest, with a variation range of about 10 day.

Flowering management

The flowering management of pear trees is very important. If the flowering period of pear trees is not properly managed or left unchecked, it will easily lead to the phenomenon of full flowers and half fruits, low fruit setting rate and low economic benefits. Adopting the following methods to strengthen the management of pear flowering period can improve the fruit setting rate, fruit quality and economic benefits.

Topdressing before flowering: Topdressing before flowering can improve the quality of flower buds, meet the nutrition consumed by flowering and improve the fruit setting rate. Quick-acting fertilizer, mainly compound fertilizer, can be applied in the first half of the flower. Generally, 0.5- 1 kg is applied to each adult tree, and 1-2 kg of urea can be added to weak trees, and the fertilizer application amount should account for 10- 15% of the whole year.

Pruning before flowering: pear trees with light pruning and large flowers should be pruned again, mainly to remove weak branches, diseased dead branches and over-dense branches, adjust the load of fruit trees, and determine the amount of flowers according to the amount of fruits left. Generally, the amount of flowers left is 65,438+0-2 times more than the amount of fruits left, and only 65,438+0 flower buds are left on each fruit table to remove redundant flower buds, which is responsive to pruning.

Flower thinning and artificial pollination: pear flower buds are compound buds, with as many as 5- 18 flowers per inflorescence. Flowering consumes a lot of nutrients in the tree, which can make the nutrient supply of the tree centralized and improve the fruit setting rate. When the inflorescences are separated, the flowers can be thinned, and each inflorescence has 1-2 flowers. For varieties with low self-pollination rate, pollination trees should be arranged. If pollinated varieties are not arranged, artificial pollination shall be carried out. During artificial pollination, fully developed buds or newly opened flowers should be collected from adult trees of suitable pollination varieties 2-3 days before pollination, and anthers should be taken, dried in the sun to make powder, and manpower should be concentrated for artificial point feeding in full bloom.

Spraying boron at flowering stage: boron can promote the germination and elongation of pollen tubes and promote the transport of sugar in trees. Spraying boron at flowering stage can improve the fruit setting rate of pear trees. When flowering is 25% and 75%, 0.3-0.5% borax (acid) solution and 0.3-0.5% urea can be sprayed 1 time respectively, which requires a lot of phosphorus and potassium for flowering.

Frost prevention in flowering period: pear trees bloom early, mostly before late frost, and are easily affected by late frost. After the pear flower is frozen, the male and female stamens turn brown, dry and shrink, and cannot bear fruit. There are several ways to prevent frosting:

1. Irrigation before flowering can reduce ground temperature, delay root activity, delay flowering, and reduce or avoid the harm of late frost.

2. Painting the trunk white before flowering can make the temperature of the tree slowly rise and delay flowering for 3-5 days, thus avoiding or alleviating the freezing injury.

3. Smoking prevents frost. Smoking can reduce the radiation of soil heat and play a role in moisturizing. At the same time, smoke particles can absorb water, make water vapor condense into liquid and release heat, increase ground temperature and reduce or avoid freezing injury. The flowering period depends on the local weather forecast. When the temperature is likely to drop to -2℃, it is necessary to prevent frost. Commonly used smoking materials are sawdust, straw, firewood and leaves, which are stacked layer by layer and staggered, with kindling inserted in the middle, which is convenient for igniting smoke. Before smoking, you must organize personnel to be on duty, hang a thermometer at a distance of 1 m from the ground, and record the temperature regularly. If the temperature suddenly drops to 0℃ in the morning, it is necessary to ignite and smoke. You can also use anti-frost smoke agent to prevent frost. The commonly used formula is ammonium nitrate 20-30%, sawdust 50-60%, waste diesel oil 10% and pulverized coal 10%. The finer ammonium nitrate, sawdust and pulverized coal, the better. Mix in proportion, put in iron drums, and ignite when using, with the dosage of 2-2.5 kg per mu.

Eliminate pests and diseases

1. Pear rot mainly damages the bark of main branches and lateral branches, causing rot. There are two kinds of symptoms: ulcer type and dead branch type. In severe cases, a large number of dead branches appear until death. It is necessary to strengthen orchard management, control fruit setting, improve the disease resistance of trees, and select disease-resistant varieties. Cut off diseased branches and scars in time, burn them centrally, and apply thiram wettable powder 30 ~ 60 times. Spraying 40% thiram-arsenic wettable powder 100 times or puti 100 times, or Pomei's 5-degree stone sulfur mixture on pear trees before germination.

Second, pear black spot disease is a common and frequently-occurring disease of pear trees, which mainly harms fruits, leaves and new shoots. In general, leaf spot disease appears in Liaoning Province from late April to early May, with an average temperature of 65,438 03℃ to 65,438 05℃, and the most serious disease occurs in May and June. However, the fruit usually starts to get sick in early May, cracks and falls off in mid-June, and the fruit falls off most in late July. The key point of prevention and control is to strengthen cultivation management, increase application of organic fertilizer and avoid partial application of nitrogen fertilizer. Combined with winter pruning, remove dead branches, fallen leaves and diseased fruits in the garden and bury them deeply. In seriously ill orchards, the mixed solution of 0.3% sodium pentachlorophenol and 5Be sulfur mixture was sprayed before the trees germinated, and Bordeaux solution with 200 times lime volume, or 50% amobam 1000 times solution, 10% polycyclic serine wettable powder 1000+ was sprayed. Alternating use of the above chemicals with Bordeaux mixture can improve the control effect and reduce the cost.

3. Dendrolimus punctatus is the main leaf-eating pest of pear trees, which damages flower buds, buds and leaves with larvae. It can happen twice a year, usually once in March-April and once in August-September. When the overwintering larvae emerge from the sting, it is the suitable period for control, that is, the period from flower bud to inflorescence separation of pear trees. Commonly used pesticides are: 50% parathion emulsion 1500 times, 50% phoxim emulsion 1000 times, 50% fenitrothion emulsion 1000 times, 50% malathion emulsion 1000 times, and 50% dichlorvos emulsion/.

Four, pear real peak (commonly known as flower diamond, white diamond worm) is only harmful to pear trees. Adults lay eggs in the calyx, and larvae first feed on the inner ring at the base of the calyx. After being blackened, they eat into the core of the fruit, making the young fruit dry and fall off. The larva crawls out before the fruit falls, endangering other young fruits. The insect has one generation a year and overwinters in the soil with mature larvae as cocoons. Adults emerge and lay eggs from late April to early May, and the peak of laying eggs is when the inflorescence of pear tree is separated until the petals appear, and the larvae eat fruit in the middle and late May.

During the prevention and control, the adults can be suspended in suspended animation, and a piece of cloth can be lifted under the canopy to shake off the adults and kill them, or the eggs, flowers and young fruits with insects can be artificially removed during the spawning period. Before pear blossom 10 ~ 15 days, when adults are unearthed, spray 25% parathion 300 times solution, 25% phoxim 300 times solution or 40.7% dimethoate 600 times solution on the ground, focusing on trunk circumference 1 m. [2-3]