What are the causes and countermeasures of yellow leaves of sand cypress?

Sabina vulgaris is evergreen all the year round, with low plants, peculiar crown shape and dense branches. It is a good evergreen cover plant in the north, but the leaf yellowing may occur in the planting process, so what are the causes and countermeasures of Sabina vulgaris leaf yellowing?

1. The dry soil leads to the yellowing of leaves.

Although Sabina vulgaris is suitable for dry sand growth, if it is in the dry environment of soil and air for a long time, it is easy to show the phenomenon of whitening and yellowing in the lower leaves of branches. If it is not grafted seedlings, especially those that do not use Platycladus orientalis as rootstocks, it is more likely to show this situation.

Prevention and control countermeasures:

Water should be properly watered until thoroughly. At the same time, Sabina vulgaris asks for a loose and permeable ecological environment. If the soil is too wet for a long time, the plant will cause rotting roots and leaves yellowing due to hypoxia, especially the new leaves. Therefore, the amount of irrigation should be controlled and the soil should be properly loosened and breathable. Sometimes excessive fertilization can also cause leaf yellow, so the amount of fertilizer application should be controlled.

Second, diseases lead to yellowing of leaves.

The pathogen filaments of cypress rust overwintered on cypresses, and the winter spores matured from February to March the following year, and the galls swelled and cracked. When the conditions were right, a large number of basidiospores occurred and began to infect the host. The re-hosts are Begonia, Hawthorn, pear, apple and other Rosaceae plants. Rust spores occurred in early May and reached the peak in June. The rust spores matured from August to September and spread to conifers such as Sabina vulgaris by wind.

The disease seriously damages the needles and tender shoots of Sabina vulgaris. At the initial stage of the disease, the leaves showed orange-yellow, glossy small disease spots, and then gradually expanded, and there were needle-sized yellow spots on the disease spots. When the weather was wet, mucus was secreted on them, and the yellow spots turned black after drying, which was the sexual spore organ of the pathogen. In the coming year, basidiospores germinate in case of rain, which is spread by wind and rain. In warm and rainy years in spring, the disease is serious. If the twigs and leaves show fragmentary yellow spots, it is generally the disease.

Prevention and control countermeasures:

Cut off diseased branches in winter. Spraying 0.3% pentachlorophenol sodium and 1 Baomedo stone sulfur mixture on Sabina vulgaris from October to November can prevent the infection of rust spores. In the middle and last ten days of March, spray 1 wave to 2 Baume of stone sulfur mixture or equivalent 160 wave to 200 Baomedo Bordeaux solution 2 to 3 times, once every 7 to 10 days before winter spore germination, the result is better.

Third, insect pests lead to yellowing of leaves

If Sabina vulgaris shows a small area of yellowing, after eliminating the disease, it may be damaged by stem borer (such as longicorn beetles). Check the branches carefully to see if there are defecate holes or break withered and yellow branches to see if there are insect tracks injured by longicorn beetles.

Prevention and control countermeasures:

Strengthen the conservation and management of Sabina vulgaris, strengthen the tree potential, and reduce the opportunity of pest invasion. Use a syringe to inject 30 to 50 times 80% dichlorvos EC into the wormhole in the branches of Sabina vulgaris to poison the larvae. The sawdust and insect dung in the insect track were eliminated before injection, and the entrance was sealed with clay after injection. If the pest is serious, it can be eliminated and destroyed.

4. Physiological chlorosis

If the tiled Sabina vulgaris shows a large area of yellowing, no diseases and insect pests have been invented, and the soil is moderately dry and wet, it may be physiological yellowing of Sabina vulgaris. The leaves of chlorosis turn yellow at the initial stage, and then appear yellow and white, especially the new leaves. In severe cases, the leaf tissue died, which affected the normal photosynthesis, and then the whole plant died slowly. Usually, there are many alkali salts in soil and water in the northern region, which affects the reception of iron ions by plants, resulting in physiological iron deficiency and chlorosis.

Prevention and control countermeasures:

Ferrous sulfate can be mixed with fertilizer. Ferrous sulfate 2.5 kg to 3 kg, oil meal 5 kg to 7.5 kg, dung 10 kg to 15 kg, water 200 kg to 250 kg mixed, ripened into black can be applied; spray 0.2 ‰ ferrous sulfate solution, the leaves are sprayed on the front and back, once every 3 days, several times in a row, can improve the yellowing phenomenon of tender leaves.