Control methods of diseases and insect pests of lettuce

Lettuce is a kind of vegetable with high economic benefit, which has very high edible and planting value, so it is more common in our country, but once it is disturbed by diseases and insect pests, it can not be eaten, so we should pay attention to the prevention and control of diseases and insect pests. So what are the diseases and insect pests of lettuce? Let's take a look at the prevention and control methods of common diseases and insect pests in lettuce.

1. Soft rot

Soft rot mainly occurs in the late growth stage or heading stage of lettuce, its pathogen is mainly latent in the soil or diseased plants overwintering, in the transmission of infection through watering and fertilization, usually when the plant appears a wound, the infection invades from the wound. At the initial stage of the disease, the infection was infiltrated and translucent, and with the development of the disease, irregular watery spots were formed, with brown sticky matter and stench, which finally led to the decay of the whole seed bulb.

Control methods: ploughing and soil preparation, using the sun to sterilize, remove diseased plants, reduce pathogens, strengthen fertilizer and water management, apply organic fertilizer, improve disease resistance, and pay attention to drainage after rain to avoid damage to the root system caused by stagnant water in the field. When diseased plants are found, they are removed and taken out of the field in time, and then the disease points are disinfected. At the initial stage of the disease, 50% can be sprayed with 500 times of the wettable powder or 5000 times of streptomycin sulfate, once a week, and the spraying times are determined according to the severity of the disease.

2. Downy mildew

The main diseases in lettuce production during downy mildew usually occur in spring and autumn, which can be damaged from seedling to adult plant, and the damage of adult plant is more serious. It mainly harms the leaf part of lettuce, when the disease occurs, the leaf appears light yellow disease spot, and the downy mildew layer appears on the back of the leaf in the humid environment, and when it is serious, it will spread to the leaf surface, and in the later stage of the disease, the leaf will die.

Control methods: reasonable rotation, reduce the degree of disease, use high border or plastic film mulching cultivation, select varieties with strong disease resistance, and disinfect the seeds before sowing. Strengthen fertilizer and water management, apply organic fertilizer as base fertilizer, apply sufficient base fertilizer, apply little or no topdressing as far as possible, reasonably close planting, increase permeability and reduce the incidence of diseases. It was found that the diseased plants were pulled out in time and taken out of the field for centralized burning, and Jinlei and Prike liquid agents were sprayed to control them at the same time.

3. Sclerotinia disease

Sclerotinia sclerotiorum mainly harms the base of the stem of lettuce, when the disease occurs, a yellow-brown waterlogged spot appears at the base of the stem, and finally the disease develops and gradually spreads to the whole stem, making it appear rotten leaves and rotten heart, and finally the whole plant wilts and dies. Flocculent mycelium was also produced in the lesion at high temperature, which was later transformed into black mouse fecal sclerotia.

Prevention and control methods: clean up the field after harvest, clean up the sick and residual leaves, dig deep into the soil, spread quicklime, turn the ground, make ridges, water, and finally cover the plastic film strictly, using this method to kill the bacteria in the soil. When it occurs, it can be sprayed with 40% sclerotiorum wettable powder 500 times or 45% Teketo suspension 800 times.

4. Insect pests

Lettuce is a leafy vegetable, and its leaves are green and tender, not only do we like it, but aphids also have a special preference for it. They often gather on the leaves, constantly sucking the juice of the leaves, so that the mesophyll tissue disappears, leaving only one epidermis, and it is best to wither and die.

Control method: when aphids break out, use 1500 times solution of imidacloprid wettable powder or yellow board to trap and kill.

The above are the prevention and control methods of lettuce diseases and insect pests. I hope I can help you. If you want to know more about vegetable cultivation, please follow us.