What are the common diseases of rice in cash crops? What kind of medicine should I take? How to prevent and cure it?

Rice is not only a kind of herbaceous rice, but also the most important and oldest kind of grain in rice. It belongs to direct cash crops. What are the common diseases of rice? What kind of medicine should I take? How to prevent and cure it? Let's learn more about it.

In the whole growth period of rice, there will be a variety of diseases, but the common diseases are rice blast, bacterial leaf spot, bacterial blight, sheath blight, rice false smut and so on.

1. Rice blast

Rice can occur from seedling to heading. According to the symptoms of the disease in different growth stages and different parts, it can be divided into five types: seedling rice blast, leaf rice blast, node rice blast, panicle rice blast and grain blast.

1. Main symptoms

(1) Seedling rice blast: the diseased seedlings turn gray-black at the base of the stem near the ground, and the upper part is reddish brown, causing the whole seedling to curl and die.

(2) Leaf rice blast: it can occur on both seedlings and adult leaves. There are four different shapes of plaques:

A, acute type of disease spot: generally oval, but also irregular, disease spot dark green, watery, dense gray mold layer.

B, chronic plaque: the spot is brown and spindle-shaped, the outer yellow is the toxic part, the inner brown is the necrotic part, and the central gray is the collapsing part. when the weather is wet, there is a gray-green mildew layer on the back of the plaque.

C, brown disease spot: the spot is brown, very small, limited to the veins of leaves, and is common in disease-resistant varieties.

D, white spot: the spot is white, nearly round, with a size of about 2 to 4 veins.

(3) Rice blast: mainly occurred on the stem node, easy to occur at the jointing stage, needle-sized brown spots appeared at the initial stage, and then extended to the whole node or part of the node became dark brown, the tissue was destroyed and the stem was easy to break.

(4) panicle rice blast: also known as panicle neck blast, which mainly occurs on panicle neck and branches. Ear neck disease, the disease spot brown or gray-black, spread from the ear neck up and down, can be as long as 3-4 cm. When the disease is early and serious, it will cause white ear, and panicle neck blast will often cause panicle stem and branch break.

(5) Rice blast: mainly occurs on grains, brown or dark brown.

two。 Occurrence characteristics

The pathogen overwintered on rice straw and diseased grain, mainly through air flow and Rain Water. The disease was easy to occur at high temperature and high humidity, and the disease was more serious when nitrogen fertilizer was applied in the later stage.

3. Prevention and cure measures

(1) selecting disease-resistant varieties.

(2) seed disinfection, seeds can be soaked with prochloraz, every 10 ml with water 20 kg (2000 times solution) for seed soaking.

(3) strengthen cultivation management, achieve reasonable fertilization, pay attention to the combined application of nitrogen, phosphorus and potassium, reasonable close planting, reasonable irrigation and so on.

(4) Chemical control, 75% tricyclazole wettable powder 30g / mu, 45 kg water, uniform spray control.

2. Rice bacterial leaf spot

1. The main symptoms are damage to the leaves and sometimes to the leaf sheath. The disease spot is dark green water stain-like spot at first, and after expansion, it is limited by leaf vein to form dark green strip spot, which is transparent to light. The disease spot surface often secretes a lot of yellow bacterial pus, which is yellow gum-like particles after dry knot.

two。 The pathogen overwintered mainly on rice seeds and straw and became the primary infection source of the disease. the transmission routes were wind and rain, airflow and the introduction and export of diseased seeds. The disease is a bacterial disease, which is one of the main diseases harmful to rice production. If it is not controlled in time, it can spread in a large area.

3. Control methods (1) selection of disease-resistant varieties. (2) seed disinfection, soaking seeds with agricultural streptomycin for 2 hours, washing and sowing seeds. (3) for chemical control, agricultural streptomycin and Yekuning can be used alternately to control bacterial diseases, spray for 1 or 2 times, and then control according to the disease.

Rice bacterial blight

1. The symptoms can be divided into two types: leaf withering type and wilting type. Among the symptoms of leaf withering type, the most common symptom is that the disease spot starts from the leaf tip or leaf edge, at first it is a dark green linear short spot, and then spreads along both sides to form a long strip disease spot with wavy lines on the edge; the wilting symptom often occurs 3-4 weeks after seedling transplanting, the first seedling wilts, then develops to each leaf, and develops to other tillers, and finally the whole plant or even the whole clump wilts, loses water and dies.

two。 Methods to control bacterial blight, 20% thiobacillus copper suspension 60 g ~ 80 g / mu, 45 kg water, uniform spray control.

Rice Bad Seedling Disease

1. Symptoms of the disease can occur from seedling stage to heading stage, the color of diseased seedlings is yellowish green, the growth of diseased seedlings is higher and thinner than that of healthy seedlings, the leaves are long and narrow, and the roots are poorly developed.

two。 The pathogen overwintered on diseased rice straw or carried bacteria in the seed itself, which became the source of primary infection. The pathogen was immersed into the base of seedling stem from the wound and spread through irrigation water and Rain Water.

3. Prevention and control methods (1) select non-diseased varieties to avoid leaving seeds in diseased fields and nearby fields. (2) for seed disinfection, carbendazim and prochloraz can be used for seed treatment. If you find a diseased plant, remove it immediately.

Rice sheath blight

1. The edge of the symptom spot is brown, the center is light brown or grayish white, when it is wet, the spot is grayish green, water stain is translucent, and the spot develops from bottom to top.

two。 The pathogen overwintered in the soil and invaded directly from the stomata or lenticels. After the rice was closed, the disease was easily caused by high humidity in the field, over-close planting, poor ventilation and light transmission.

3. Control methods (1) eliminate the source of bacteria. (2) reasonable close planting, reasonable irrigation, frequent irrigation in shallow water, moderate drying and reducing field humidity can reduce the occurrence of sheath blight. (3) medicament control, 4% Jinggangmycin 1.6 billion Bacillus cereus 48g / mu, 45 kg water, or 20 g / mu hexazolol suspension, 45 kg water, spray control.

Rice false smut

1. Symptoms harm individual grains, the initial formation of mycelium in the grain, gradually increasing, so that the inner and outer glumes open, revealing a yellowish mass, that is, the spore seat of the pathogen.

two。 Control methods (1) select disease-resistant varieties. (2) seed disinfection is the same as rice blast and sheath blight. (3) combined with the prevention and control of sheath blight, Jinggangmycin was sprayed for 4 times from closing to maturity.