In recent years, the incidence of rapeseed white rust has been relatively high, seriously affecting the quality of rapeseed.
Rapeseed white rust can affect all above-ground organs throughout the growth period of rape, mainly damaging leaves and stems. When the leaves are first infected, small light green spots with a yellow halo will appear on the front of the leaves, which gradually turn yellow into circular lesions. White paint-like scars will appear on the back of the leaves. When the scars rupture, white powder will emit. In severe cases, the disease Leaves turn yellow and fall off. The top of the infected pedicel is swollen and curved, taking on the shape of a "faucet", and the flower organ is damaged. The petals are deformed, enlarged, turn green and leaf-like, and do not wither for a long time and are not strong. The lesions on the stem are oblong white scars, and the lesions are swollen and curved.
There are two peak periods from bolting to full flowering. The disease is prone to occur frequently under low temperature and high humidity environmental conditions. The disease is more common in plots with low-lying terrain, poor drainage, heavy soil, excessive watering, large temperature differences between day and night, heavy dew condensation, and excessive nitrogen fertilizer application.
Prevention and treatment of this disease can start from the following aspects. First, it is necessary to select disease-resistant varieties. Mustard type and rapeseed are highly resistant, followed by cabbage type. Cabbage type is susceptible to diseases and can be selected according to local conditions; second, it is necessary to rotate with grass crops for 1 to 2 years or to rotate crops between floods and droughts; third, it is necessary to strictly eliminate diseases. Seedlings, when "faucets" appear, cut them off in time and burn them intensively; fourthly, fertilize properly and clear ditches and drain away stains.
During the bolting period of rapeseed, Chlorothalonil75% WP 600 times liquid, or Zineb65% WP 100-150g/667 square meters, or Metalaxyl25% WP 50-75g/667 Square meters, spray 40 to 50 kilograms of water evenly, once every 7 to 10 days, spray 2 to 3 times, which can effectively prevent the occurrence of diseases.
At the early stage of flowering, you can spray Chlorothalonil75% WP 1000-1200 times liquid + Metalaxyl25% WP 500-600 times liquid, or Metalaxyl 58% ·Mancozeb WP 500 times liquid , control 2 to 3 times continuously, with an interval of 7 to 10 days between each time, which has a good control effect on white rust.
Post time: Mar-25-2024
