What is the difference between the two rice diseases? Explained clearly in one article

In recent years, bacterial brown spot of rice has shown a trend of relatively severe occurrence in some rice areas of our province. Most farmers mistakenly treat this disease as rice blast, which both increases costs and fails to achieve good results. For this reason, the two diseases are specifically distinguished below.

1. Symptoms. The symptoms of bacterial brown spot of rice are that reddish-brown small spots first appear on the upper leaves of the rice starting from the leaf tip and leaf edge, then expand into spindle-shaped, long oval, or irregular strip-like streaks, gradually spreading to the entire leaf, causing local necrosis of the leaf, with no bacterial ooze or mold layer visible. Seen from a distance, the rice field is a stretch of bright red. Rice blast, by contrast, generally begins with brown spots appearing on the lower leaves of the rice, and the underside of the lesions is densely covered with a gray mold layer. In severe cases, the lesions are densely distributed, the leaves wither and scorch, the whole plant is poisoned and stunted, and the stems rot and die.

2. Conditions for onset. Bacterial brown spot of rice is caused when the plant suffers physiological potassium deficiency due to potassium deficiency in the soil or excessive application of nitrogen fertilizer, and bacteria invade through the plant's stomata to cause disease. Rice blast, by contrast, is caused by continuous rainy weather, insufficient sunlight, or alternating sunshine and rain; high temperature and high humidity, and muggy weather make it prone to occur.

3. Control methods. Bacterial brown spot of rice: this disease is generally not contagious, but may spread with changes in the weather. If suitable conditions for onset are encountered at the heading stage, bacterial brown spot of the flag leaf or black grains may appear. Generally, mild bacterial brown spot does not need control; after heading, most grains can fill, but the filling speed is slow and the milled rice yield is low. If the disease is severe, chemical control is used. Currently, commonly used chemicals on the market include "Yeqingshuang", "Longkejun", "Miejuncheng", "Mengkejun", and others. When applying the chemicals, add potassium dihydrogen phosphate as well, and the effect will be better. Irrigate with shallow water, and avoid one-sided application of nitrogen fertilizer. Control of rice blast:

1. Select disease-resistant varieties suitable for the local area.

2. The first-choice chemical for control is "Fuji No. 1", followed by "tricyclazole", "kasugamycin", and others. Seize the key period and spray when the panicle is emerging. Use the dosage according to the instructions. Be sure to use sufficient water volume. Ensure two sprayer loads of water per mu (667 sq m) (each load 30 kg). In areas where rice blast occurs heavily, spray again after one week.

3. Adopt formula fertilization technology, control nitrogen fertilizer, and achieve alternating wet and dry conditions when irrigating in the middle and late stages.