Prevention of Five Physiological Diseases in Rape

1. Insufficient nitrogen fertilizer at the seedling stage, the leaves are uniformly yellow-green or yellow in color, and some of the leaves on the lower part of the stem are reddened and gradually expanded to the veins. Yellow leaves appear. Per acre can be used 7 to 10 kg of urea or ammonium bicarbonate 15 to 20 kg or 1000 kg of human waste water application, can also be used 1% urea foliar spray.

2. Sulfur deficiency at the seedling stage, small and small leaves, pale greenish yellow leaves, combined with 5 kg of osmotic plaster.

3, leaves only yellow and then fall off, is a yellow leaf sour, per acre can be applied 50 kilograms of lime or 50 kilograms of ash.

(b) Red leaf disease

1. Dwarf plants at seedling stage are short and the leaves are yellowish red. The symptoms should be promptly filled with water.

2. If there is too much rain during the seedling stage, the water will be damaged and the seedlings will be stiff and the leaves will be dark red.

3, broadcast sowing field too large, crowded vegetables, affecting the nutrient absorption of seedlings, leaves turn yellow and red, then time and seedlings should be applied once and available nitrogen fertilizer.

4. The weather at the seedling stage is dry, and the places where the vegetables are damaged may cause reddening of the leaves. In addition, maggots are also the mediators of the virus, so it is important to grasp locust control. Can use garlic juice or anti-influenced water spray control.

(c) Brown coke leaves

This is caused by the lack of potassium in the soil. It starts from the old leaves and gradually develops into the heart and leaves. The yellow spots appear at the beginning, and the edges of the leaves gradually appear as coke-edge and light brown spots, showing obvious scald and withering. When this occurs, 7 to 10 kilograms of potassium chloride or 80 to 100 kilograms of plant ash may be applied per acre, or 20% to 3 times of 60 kilograms of potassium dihydrogen phosphate may be applied to 60 kilograms of water.

(d) Dark purple disease

The plants grow slowly and are dwarf, with 2 to 3 leaves less than normal plants. The leaves are dull, the petiole is purple, and the edges of the veins are purple spots or purple patches. This form is caused by the lack of phosphorus, per acre can apply calcium phosphate 25 to 30 kilograms, or with 80% potassium dihydrogen phosphate 100 to 150 grams of water 60 kilograms of leaf spray 2 to 3 times.

(v) Violet blue leaf disease

Caused by the lack of boron. When the rapeseed lacks boron, some roots have small nodules, root neck enlargement, no root hairs or lateral roots, dark green leaves, small and crisp leaves, and purple blue spots, leaf margin rewind. For the lack of boron blocks, 150 grams of borax can be used per acre with phosphorus and potassium fertilizers applied or mu 100 grams of borax 50 kg of water for foliar spray, continuous 2 or 3 times.