Introduction to the key techniques of pest control in citrus

Citrus tree is one of the common tree species in orchard, which usually bear yellow fruit and hang all over the branches in autumn and winter. Citrus taste sour and sweet, rich in vitamin C, is very popular in the market. In the specific process of citrus planting, there are often some diseases. Today, let's take a look at the key technical points of citrus pest control.

1. Scab

Occurrence regularity: when it is rainy in spring and the temperature is more than 15 ℃, the overwintering pathogen produces conidia and invades new tissues. Scab can spread rapidly after moderate rainfall and temperature rise.

Prevention and control methods: seize two key periods of spraying to protect citrus shoots and young fruits. One is the sprouting of the spring bud, the first time the bud is sprayed when the bud grows a grain of rice, and the other is the second time when the flower falls at 2/3. In case of cloudy and rainy weather, the effect of pesticide application is not good, but also in the early May young fruit period spray again.

Medicament selection: difenoconazole, tebuconazole + mancozeb, etc.

2. Anthrax

Occurrence regularity: it generally occurs in April to June every year, causing fallen leaves, flowers, fruits and branches to die. Especially in the case of more continuous rain in spring, it is a favorable period for the spread of conidia, resulting in a large area of orange orchard damage.

The disease also has the characteristics of latent infection, spring shoots in a month after germination, branches and leaves begin to carry bacteria. By the end of autumn, most of the branches and leaves of the new shoots were infected with bacteria in the same year, and the disease could be caused the next year when the conditions were suitable.

Prevention and treatment: spray at the tender tip stage to protect and prevent scab. Focus on the young fruit stage, spray every 15 days or so, 3-4 times in a row. Spray must be thoughtful and uniform, especially to fully spray fruit stalks, fruit branches and fruit mother branches, spray wet branches and leaves without dripping as the standard.

Medicament selection: difenoconazole, prochloraz, propionate zinc, etc.

3. Brown spot

The occurrence regularity: it generally began to occur in late March, the peak period was in late spring and early summer, and the optimum temperature was 22-28 ℃. The orchards with poor drainage, weak tree potential and many tree wounds occurred seriously.

Prevention and control methods: proper pruning, reasonable water and fertilizer, timely spraying chemical protection. Spray at intervals of about 10 days before and after spring shoot 3~5cm, flowering stage, young fruit stage and rainy day.

Drug selection: Prozac zinc, pyrazole, etc., pay attention to the use of internal inhalation conductive therapeutic drugs, especially after the onset of the disease.

4. Ulcer disease

The occurrence regularity: the optimum temperature was 25-30 ℃, and the peak period in spring was from late April to early May. Young trees, young trees are more susceptible to disease, high temperature and rain, leaf moths and other pests occur, the canker disease is serious.

Prevention and control methods: pay attention to prevention, medication frequently, do a good job of wiping and controlling tips, and release them uniformly. Results the trees could be sprayed once at 10 days, 30 days and 50 days after falling flowers, and the young trees and seedlings were sprayed once at 20-30 days after each shoot germination, and the phosphorus and potassium source pool was applied to promote the ripening of new shoots and reduce the damage cycle of leaf miner.

Medicament selection: copper preparations, thiazolyl zinc, mancozeb, pyrazole carbendazim, etc., pay attention to rotation, compound use. However, it is necessary to avoid copper preparation + copper preparation, so as to avoid superimposed drug damage.