Ten kinds of common rice diseases and insect pests and their scientific control methods

Diseases and insect pests are one of the important hazards in the process of agricultural production, which have a great impact on the yield and quality of crops. Rice, as a staple food for Chinese people, is also greatly affected by diseases and insect pests in the process of growth. The following editor will introduce ten kinds of common rice diseases and insect pests as well as scientific control methods.

Rice black sclerotia culm rot

Symptoms: a fungal disease at the base of the stem of rice at the adult stage, the pathogen invades the leaf sheath at the base of the stem, forming oval or spindle-shaped black spots, then expands to the whole leaf sheath, and there are also large black spots on the stem, which rot at the base of the stem in the later stage, and the plant is green and withered. There are a large number of small globular black granular sclerotia in the stem cavity.

Prevention and control methods: to strengthen fertilizer and water management, combined with pest control and disease prevention, supplemented by timely spraying.

2. Rice bacterial blight

Symptom: a bacterial disease in the leaves of rice that invades the rice from wounds or pores in the roots, stems and leaves and propagates in the ducts of the vascular bundles. Seedling stage and tillering stage are the most vulnerable. Most of the seedling leaves showed the symptom of leaf withering. Most of the infected varieties showed acute wilting symptoms, the disease spots were bluish gray and waterlogged, the diseased leaves curled and withered rapidly, and brown spots appeared on the resistant varieties.

Control methods: selection of disease-resistant varieties, prevention of flooding in rice fields is the key to disease control, combined with chemical control.

Rice dwarf disease

Symptom: a virus disease on rice seedlings, which can be infected in the growth stage of rice, and the seedling stage and tillering stage are susceptible to the disease. The earlier the disease occurs, the greater the loss. If the disease occurs at the seedling stage, the diseased plants are obviously non-tillering and seriously dwarfed; at the tillering stage, the diseased plants are susceptible, the tillers increase and appear clumpy, and there are inverted fibrous roots and high node branches in the nodes of the diseased plants; in the seedling and tillering stages, most of the diseased plants can not heading, although some of the main stems can still heading, but most of them contain panicles, and the seed setting rate decreases.

Control methods: the prevention and control of virus-transmitting insects is the key to disease prevention.

4. Evil seedling disease of rice

Symptom: a fungal disease of rice aboveground, which can occur from seedling stage to heading stage. The diseased plant is overgrown, thin and yellowed, usually 3 to 10 cm taller than the healthy plant, so it is easy to identify. There are often inverted aerial roots and pink mildew layer on the basal nodes of diseased plants. The optimum temperature for the development of the pathogen was about 25 ℃, and the seeds carried the bacteria.

Control methods: the selection of disease-free seeds or soaking seeds with chemicals before sowing are the key measures for prevention and control.

Rice sheath blight

Symptoms: it is a fungal disease, which often occurs from the late tillering stage to the heading stage of rice. The infection site of the disease gradually spreads from the bottom of the initial rice stem to other parts, and the most serious one will spread to the panicle of rice. When the dark green water-stained disease spot appears in the root and stem of rice, and the disease spot changes from small to large, and the rice leaf dies, it can be judged that it is infected with rice sheath blight, and measures should be taken against the disease in time.

Prevention and control methods: it should be mastered when the rate of diseased plants at booting stage reaches 30% to 4%. The liquid should be sprayed on the middle and lower parts of the rice plant. Using the pouring method, the field should maintain a 3-5 cm watering layer. When applying Jinggangmycin, it is best to do it on a sunny day after rain, or when there is no heavy rain within two hours after application. Use 5% of Jinggangmycin water 100ml to 150ml, or Jinggangmycin high concentration powder 25g, either spray 100 kg of water routinely or pour 400 kg of water.

6. Grey planthopper

Most of the eggs are laid on barnyardgrass in rice fields, and the spawning sites are all in the lower leaves of rice, wheat, barnyardgrass and the midrib tissue at the base of leaves. It can also spread rice, wheat, corn and other black streaked dwarf disease, striped leaf blight, wheat clump dwarf disease, corn stunt disease.

Prevention and control methods:

(1) drop oil to kill insects. Drop 400 grams of waste diesel oil or waste engine oil per mu, keep a shallow water layer of 20 cm in the field, manually drive out insects, insects fall into the water and touch the oil and die. Change clear water after treatment, do not use this method after booting.

(2) spreading poisonous soil. Sprinkle with 1.5 kg dimethoate powder and 2 kg moist fine soil per mu.

(3) spraying with medicine. Spray with 40% dimethoate emulsion 0.5 kg plus water 800-1000 kg.

Rice thrips

Rice thrips are very small, adults are dark brown, winged and crawl fast. Life is divided into three stages: egg, nymph and adult. Similar to adults, nymphs are yellowish, small, wingless, often curled at the tip of rice leaves, and suck up the sap of rice leaves. The killed rice leaves lose water and curl, the rice seedlings turn yellow, there are dots of white spots on the rice leaves, and the heart leaves shrink, which looks like burning from a distance. Rice thrips gather when they blossom.

Prevention and control methods: because the rice thrips are very small, in general, it is not easy to attract people's attention, but only when the rice is seriously harmful and causes a large number of rolled leaves. Therefore, it is necessary to check in time to eliminate the rice thrips in the larval stage. Use 40% dimethoate emulsion 1500-2000 times per mu, and keep the water layer after application in seedling fields and fields. After the control of rice thrips, quick-acting fertilizer should be applied to promote the growth of seedlings and tillers.

8. Rice bract insect

The larvae feed on the mesophyll in the bracts, leaving the epidermis, forming white spots of different lengths. If it is damaged in the later stage, it is mainly the damage of two nutritious leaves below the flag leaf, which seriously affects the photosynthesis and nutrient accumulation and transport of rice plants, resulting in unsubstantial grains and more dry chaff, resulting in a reduction in yield.

Control methods: 2.5% trichlorfon powder 2 kg spray powder or methyl 6 powder 1 kg fine soil 10 kg poisonous soil; 90% crystal trichlorfon 150 grams plus water 80 kg 100 kg spray.

9. Rice leaf roller, Chilo suppressalis

The larvae begin to spin silk in the heart leaves of rice, rolling both sides of the leaves into tubular bracts, and the worms hide in the bracts to feed on the mesophyll and upper epidermis, and endanger them in the tender leaf sheaths after heading. In severe cases, the rolled leaves only have transparent and whitish epidermis, and the whole leaves die.

Control method: spray with 25% 223 emulsion 250 times and 90% trichlorfon 1000-1500 times. The control time should be controlled before the third instar of the larvae, and the effect of medication in the evening is the best. After prevention and treatment, the effect should be checked, and if the population density is the same as before, it should be treated again.

Ten. Chilo suppressalis

It has a single feeding habit, feeds exclusively on rice, causes stem decay of larvae, forms a withered heart at tillering stage, forms withered booting and white panicles from booting to heading stage, and forms insect-injured plants when transformed into plants. "withered seedling" and "white ear" are the main symptoms of rice plants.

Control method: during the incubation period of ant borer, the breaking period is the best time to control white spike. When the break is 5% to 10%, the pesticide is applied once, and the number of nymphs is large, and then add 1 to 2 times, with an interval of 5 days.

The above is a full introduction of common rice diseases and insect pests and scientific control methods. In the process of prevention and control, pesticides should be used scientifically and safely to prevent their pollution to agricultural products and the environment, so as to ensure food safety and human health.