Prevention and Control of Root swelling Disease in Brassica napus

Rape root swelling disease is a spindle-shaped or irregular deformed "tumor" in the root, with more on the main root and less in the lateral root. At the beginning, the surface of the "tumor" is smooth and white, and then gradually brown, rough and cracked. These cracked "tumors" are easily infected by germs and rot and stink.

Rape root swelling disease

First, symptoms: in the early stage of the disease, at noon, due to high temperature, rape transpiration is large, water loss is fast, but because the root is destroyed by "tumor", the ability of absorbing water and fertilizer is poor, at this time, the upper part of the diseased plant is easy to wilt; in the morning and evening, rape transpiration is small, water loss is less, will not wilt. However, with the deterioration of the disease, infected rape will wilt completely and even die.

Second, prevention and control methods:

1. Prevention. First, we should start with cultivation and management, eliminate or reduce the number of bacteria in rape field from the source, and create an environment conducive to rape growth but not conducive to pathogen growth.

Methods: rape seeds should not be transferred from disease areas; rotation with rice should be carried out with other non-cruciferous crops, and rotation should be carried out for 4-5 years in seriously diseased fields; drainage facilities in rape fields should be improved, deep ditches and narrow beds should be cleared, ditches should be cleared to prevent soil moisture; do not grow rape on low-lying waterlogged land or acid soil; fly ash compound fertilizer can be used to improve soil; seedlings without root swelling disease should be selected to prevent the spread of bacteria. After rape harvest, the diseased and residual plants of rape should be burned or composted. Note: compost must be mature before it can be used. Take the above measures, can reduce the incidence of the disease, but not without the disease.

2. Governance. When a small amount of root swelling disease rape plants appear in the field, they should be pulled out in time and disinfected with quicklime in the disease hole. If there are more diseased plants, the root can be irrigated with 50% carbendazim wettable powder 500 times solution, 250 ml per plant, or 40% pentachloronitrobenzene powder 500 times solution, each plant 400-500 ml, can also effectively control the disease.