Pruning technique
1. Timely trunk cutting: After the growth stops in spring and before the arrival of the second growing season (usually in early July), cut off the curved part at the top, and after the new branch is sent out, choose a vertical branch as the new trunk.
2. Reasonable pruning: The so-called reasonable pruning means to keep as many side branches as possible without affecting the growth of the trunk, which is conducive to the thickening and growth of the trunk, speeding up the lignification process and avoiding the bending of the trunk. Under the specific operation:
(1) Horizontal branches and branches close to horizontal branches are generally not cut, so let them be pruned naturally.
(2) The competitive branches that affect the growth of the main spike should be cut off in time.
(3) Control the growth of other lateral branches that do not form competitive growth, and cut them off in time when their thickness reaches 1/2 of the trunk thickness. Prevent the trunk from being too sharp and increase the height of the trunk. If it is cut too late, the wound is not conducive to healing.
3. Re-shaping: When the 2-3-year-old seedlings begin to grow in spring, if the seedlings have no obvious main spikes or have main spikes but are too skewed, they should be reshaped and cut off again, and the incision should be selected at the position where they begin to skew.
4. Maintain a reasonable density: the ground diameter of small seedlings is 50px, with 45,000 ~ 50,000 plants per hectare, and the DBH of large seedlings is above 1 12.5 px, with about12,000 plants per hectare. This not only ensures the photosynthetic needs, but also meets the requirements of natural pruning.
5. Other measures: applying more phosphorus and potassium fertilizer in seedling stage and topdressing on leaves in growing season are beneficial to strengthen photosynthesis, speed up lignification process and prevent trunk bending. In short, if you want to cultivate qualified Sophora japonica seedlings, you must master three points:
(1) Cut dry in time and replace the nose.
② Avoid excessive pruning.
③ Maintain a reasonable density.
control of insect
1. locust
It occurs for many generations a year. Adults and nymphs gather on the twigs, inflorescences and pods of branches, sucking the juice, and the damaged twigs atrophy and droop, which hinders the top growth. The seriously damaged inflorescences cannot bloom and die, and sooty blotch is induced at the same time. The insect began to multiply in large numbers in early and mid-March, produced winged aphids in April, migrated to Sophora japonica in early May, and suffered the most damage in May and June. In early June, she moved to weeds to live, and in August, she moved back to Sophora japonica to live for a period of time, and wintered with wingless viviparous female aphids and a few eggs in the root zone of weeds.
Prevention and control methods:
(1) Spray sulfur mixture in autumn and winter to eliminate overwintering eggs.
(2) When aphids occur in large quantities, 40% omethoate, 50% malathion emulsion or 40% acephate can be sprayed 65,438+0,000 ~ 65,438+0,500 times, or 65,438+0,000 ~ 2,000 times, 65,000 times.
(3) At the early stage of aphid occurrence or before a large number of overwintering eggs hatch, dip the cotton wool with 40% omethoate emulsion for 8 ~ 10 times, surround the trunk and wrap it with plastic sheets.
2. Tetranychus cinnabarinus
It occurs for many generations in a year, and the fertilized female mites overwinter in the pores of clods, cracks in bark, litter and other places. This mite is harmful on the back of leaves. The damaged leaves were yellow and white spots at first, and then spread to the whole leaves with dense silk screens. In severe cases, the whole tree leaves turn yellow and fall off. Prevention and control methods:
(1) Prevention and control during the overwintering period: spray with sulfur mixture to scrape off rough skin and warped skin, or trap overwintering mites with sokcho in trunk, and burn them centrally in spring.
(2) Chemical control: When spider mites are found to be harmful to leaves, they should be sprayed as soon as possible to control the early damage, which is the key to control the late pests. By spraying 1000 ~ 1500 times of 40% dicofol EC, 1500 ~ 2000 times of 50% tetracycline wettable powder, 1500 times of 40% omethoate EC and 3000 times of 20% Spraying should be uniform, meticulous and thoughtful. If it is serious, spray it once every half month 1 time, and spray it continuously for 2 ~ 3 times, and the effect is good.
3. locust moth
Also known as inchworm. There are three or four generations in a year. The first generation of larvae begins in early May, and the peak period of each generation is in late May, mid-July and late August to early September respectively. Pupa overwinters in the loose soil around the trees, and larvae and adults eat the leaves of the trees, causing the leaves to carve flowers. In severe cases, almost all the leaves of the whole tree were eaten up.
Prevention and control methods:
(1) After defoliation and before germination, the pupae should be dug into and around the crown to eliminate the overwintering pupae.
(2) Chemical control: the first and second generation larvae were mainly controlled in mid-May and late June. 50% chlorpyrifos EC, 80% dichlorvos EC 1 0,000 ~10,500 times, 50% phoxim EC 2000 ~ 4000 times and 20% mirex EC 2000 ~ 40000 times can be used.
(3) Biological control can reach 600 times that of Bacillus thuringiensis emulsion.
4.Apriona germari
Every two years, it occurs 1 generation, which is mainly caused by young insects eating holes. At the beginning of March every year, the larvae begin to move, and the feces and sawdust of the longicorn larvae are suspended in the borehole. Sophora japonica, which was eaten by longicorn beetles, was weak, with yellow leaves, dry branches and even the whole plant died.
Prevention and control methods:
(1) Artificial killing of adults: The flying ability of longicorn beetles is weak, and it is easy to fall to the ground due to vibration. Female ovipositors can be killed on tree trunks at night from mid-June to late July every year.
(2) Artificial egg killing: during the spawning period of longicorn beetles from July to August every year, find the egg pieces on the trunk and break them with iron.
(3) Chemical control of adults: During the peak period of adult activity from mid-June to mid-July every year, spraying 2000 times of liquid on the crown of Sophora japonica to kill pyrethroids once every 15 days and spraying twice continuously can achieve good results.
(4) Chemical control of larvae: March to 10 every year is the active period of longicorn larvae, and 80% dichlorvos, 40% omethoate or 50% phoxim can be injected into the wormhole for 5 to 10 times, and then the larvae are sealed with toxic mud mixed with chemicals, so that the larvae are poisoned.
(5) Using lime 10 kg+sulfur 1 kg+salt 10 g+20 kg -40 kg of water as whitening agent, brush the trunk to prevent longicorn beetles from laying eggs.
5. Sophora japonica
The second generation occurs every year, and the larvae overwinter in the cracks of bark or seeds, especially in July and August. Larvae mostly feed from the base of compound leaf petiole, which causes the compound leaves of trees to dry up and fall off. In severe cases, the crown appears baldness and necrosis, which affects the appearance.
Prevention and control methods:
(1) In winter, tie straw stalks or straw ropes to the trunk to trap and kill overwintering larvae.
(2) Spraying 1000 ~ 1500 times of 40% acephate EC, 1000 times of 50% cartap EC or 1500 times of 50% malathion EC during the pest occurrence period.