HOW TO TREAT THE PEST IN GREENHOUSE FOR CUCUMBER

The greenhouse production area is expanding year by year, but due to its long-term stability and continuous planting characteristics, the soil quality in the greenhouse continues to decline, the degree of salinization increases, and there are more and more underground pests and pathogens, especially root-knot nematodes, which affect the yield and quality of cucumbers.
Root-knot nematodes are aerobic and parasitic nematodes. They especially like sandy soil with better air permeability and rich organic matter. They are very suitable for the parasitism and reproduction of root-knot nematodes, so they are most common at 5 cm in the soil layer. When conditions are suitable, nematode eggs will hatch into larvae, continue to reproduce and remain in the soil or enter the root system. They can survive for 2 to 3 years, up to 5 years.

Second-instar larvae or eggs survive in the soil and have poor mobility. They are mostly spread through diseased soil, diseased seedlings, irrigation or agricultural tools. Generally, plots that have been soaked or hardened for a long time have few or no nematodes. They directly harm the roots of crops and secrete sap that is absorbed by fibrous roots and lateral roots to form small knots of different sizes. After a long time, they will slowly soften until they rot, making the roots unable to absorb nutrients and die. Root-knot nematodes have the worst activity when the temperature is below 5°C or above 40°C. Nematodes basically cannot survive when the temperature is above 55°C for 10 minutes. Humidity is also an important condition that affects their reproduction. When the temperature is 40% to 70% or in the rainy season, it is more conducive to reproduction and growth. The survival time of each generation of nematodes is generally 7 to 8 days, up to a few weeks.
Root-knot nematode is a very harmful soil-borne disease that damages many crops, especially cucumbers. A good root system is the decisive factor for a high yield. The deeper the roots, the more luxuriant the branches and leaves will be. However, root-knot nematodes in the soil absorb most of the nutrients in the root system, causing the seedlings to wilt and die. At the same time, it will also make the root system thicker and larger, causing the nutrients absorbed by the crop root system to be unable to be successfully transported to the upper surface of the earth, thus causing poor growth, wilting, premature aging, poor stress resistance, and death of the crop. Root-knot nematode disease has become more common in recent years and is the most harmful soil-borne disease to crops. Crops infected with this disease generally experience a 20% to 50% reduction in yield, or even no harvest in severe cases, causing huge losses to growers. Therefore, the occurrence of root-knot nematodes must be controlled, both by "preventing" and "treating" them.

Root-knot nematode control methods
3.1 In agricultural prevention and control production, disease-resistant or disease-tolerant varieties should be selected. This is the basis for the prevention and control of root-knot nematodes and can effectively reduce the incidence of root-knot nematodes. Farming should be done in rotation to avoid repeated planting. You can rotate crops with leeks, peppers, garlic, wheat, corn, etc. It is best to rotate crops with gramineous crops, once every 3 to 5 years; at the same time, apply more organic fertilizers to reduce the use of chemical fertilizers to increase the content of organic matter in the soil, which can generally promote a 10% to 15% increase in crop yields; clean up the remaining branches and leaves of crops in the greenhouse in a timely manner to reduce insects and eggs in the soil; apply more microbial inoculants to improve the soil environment to effectively reduce the survival of root-knot nematodes in the soil.
Root-knot nematodes have a wide host range. They not only live in the soil, but also on seedlings and equipment. They can be spread by wind, water, diseased soil, agricultural machinery, field work, etc. Therefore, they are highly susceptible and highly transmissible. Therefore, it is strictly forbidden to borrow tools from outside, and do not go around in sheds with nematodes. You must take good protection.

Strengthen facility environmental management
There are no obvious symptoms in the early stages of crops being damaged by root-knot nematodes. Once symptoms of the disease are seen, it means that the disease is already serious. Therefore, in addition to prevention and control, greenhouses with nematodes must be treated before and after planting. Once it occurs, it is difficult to completely control it. The treatment method can be based on the length of time the greenhouse has been empty. When resting, remove all the shed film and plow the soil deeply, which can bring the worms and eggs in the deep soil to the ground. The surface soil will become loose, and the moisture content in the soil will decrease after being exposed to the sun. The soil will also become dry, and the nematodes' mobility will be worse, which is not conducive to their reproduction and survival, and can kill most of the nematodes and eggs in the soil.
Clean all the stems and leaves of the crops in the facility and keep the temperature high for about 7 days. The maximum temperature in the shed can reach over 75°C, which will directly kill almost all nematodes in the soil 5 to 10 cm above the ground. Or use lime nitrogen for in-facility disinfection. When the greenhouse is resting from June to July, after cleaning up the plant residues in the greenhouse, first spread farmyard manure evenly, then evenly spread 80 to 100 kg of lime nitrogen per acre, then plow the soil deeply to a depth of about 30 cm, then make ridges and borders, and finally cover the entire ground in the greenhouse with a film along the direction of the greenhouse. In order to achieve a seamless connection between the membranes, clamps should be used, and the edges of the membrane should also be pressed tightly. The greenhouse time should be kept for 20 to 30 days. About 10 days before planting, the film should be removed for ventilation, the soil should be plowed, and the land should be prepared. After drying for more than 7 days, you can sow or plant crops.