Occurrence and Control of Strawberry Nematode Disease in Greenhouse
I. Identification of strawberry nematode infection in greenhouses Before the ripening of strawberries, the plants were obviously poorly growing. The appearances were water shortage, lack of fertilizers, slow growth, yellowing of the base leaves, premature fall off, leaf margin scorch, late flowering, and fruit growth slow. As the fruit matures, the diseased plants show severe drought-like wilting, and the severe ones die slowly. However, although the light strains can result, the fruits are small and mature. The entire root system formed a tangled cluster of fibrous roots. The roots were covered with soil particles and sand grains. Later in the roots, brown worms were formed on the roots.
Second, the law of occurrence of nematodes are divided into five instars, mainly eggs and oocysts oocysts larvae overwintering. When the average temperature in the greenhouse reaches 11.3°C, hatching takes place. The newly hatched larvae are larvae of the larvae, which are released from the shells in the egg shells and emerge into the infestation larvae. With the increase of soil temperature, overwintering larvae and newly hatched larvae begin to move in the soil. When the average ground temperature reaches 12°C, infestation larvae can invade from the root end. Destruction of the normal growth of cells in the column, causing the abnormal development of parenchyma cells, the formation of raised tumor-like insects. The nematode ingests the strawberry sap in the galls, develops and grows, and becomes an adult after the fifth peeling. After the mating of the adult female, the female settled in the same place and continued to be harmed, and the males left the galls to the soil and drilled into other insects to mate with the females. The females die after laying eggs and the eggs hatch into infested larvae in the soil for reinfection. One to two generations can be completed during the shed period, and three generations can be completed in the whole growth period.
Third, the incidence characteristics of root-knot nematodes in well-ventilated, loose texture of the sandy loam heavy, especially the low fertility of the sandy ridge thin heavy, low-lying, re-alkaline and sticky soil incidence of light or not disease. Soil moisture content of less than 20% or more than 90% of the maximum water capacity in the field is not conducive to the invasion of root-knot nematodes. The optimum soil moisture for larvae invasion is 70%. The occurrence of continuous cropping occurred, and the occurrence of crop rotation was light, and crop rotation could control the occurrence of disease. Sit on the ground or breed a strawberry seedling with a diseased plant with insects, which can spread disease easily. When the soil temperature is 12-19°C, the larvae can invade within 10 days. At 20-26°C, larvae can invade in large quantities within 4-5 days, and higher than 26°C is not conducive to invasion.
Fourth, the prevention and control methods to strengthen quarantine; selection of nematode resistant varieties, early-maturing varieties to Fengxiang, late-maturing varieties to the All-Star is better; the same plot of planting strawberries every other year or three consecutive years of 3-4 years after replanting strawberries, during planting The nematode does not harm the crops; after the production process or harvest, remove the root and diseased plants, and burn them in a centralized manner; deep-dip the soil and increase the application of organic fertilizers to promote the robust growth of the strawberry and enhance the resistance to disease; choose disease-free and timely Nursery seedlings without nematode disease. When transplanting, dig large cockroaches to make seedlings robust; in summer, seal greenhouses, cover with black mulch on the ground, conduct high-temperature sterilization; 40% methyl isothiophosphite emulsion can be used for chemical control, according to the effective composition, 300- 400 grams, 500 grams of special weight Mushi; 10 lines kill 1 kg of Mushi, 3% carbofuran granules Mushi 5 kg, 1.8% abamectin Emulsion Mushi 1 kg.
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