prevention and control methods: ① seed disinfection: soaking seeds with 1% lime water; Strong chlorine essence disinfection. (2) Soaking the seedlings with chemicals: using 2% tricyclazole wettable powder according to the ratio of 5g to 25kg of water, cleaning the seedlings, spin-drying, soaking them in the liquid medicine for 3s, taking them out for 3min, and then planting them. ③ Spraying prevention and control: once the disease center of leaf blast appears, spray with 1,-1,5 times solution of thiophanate methyl and thiophanate ethyl in time; Fuji No.1 can also be used. Generally, 9kg of water is sprayed with 75 ml/hm2. No matter whether the field is diseased or not, 2% tricyclazole wettable powder 1.5 kg/hm2 was used to spray 9kg of water once at the break of rice heading. Ear neck blast was found after heading, and 9kg of water was sprayed with Fuji No.1 15 ml/hm2.
second, rice sheath blight
sheath blight is commonly known as flower stalk, and the middle of the lesion is gray. The edge is dark brown, and often several lesions are interconnected to form large moire patches. In the case of rainy and humid weather, the disease grows white or gray spider-silk mycelium. Later, it gradually formed a white velvet block and finally became a brown hard sclerotium.
control methods: ① remove the source of bacteria, salvage "wave residue", eradicate weeds at the edge of the field, and return to the field without sick straw; ② Rational fertilization and irrigation; ③ timely spraying: spray 1,125 kg of water with 1% (1, units) jinggangmycin wettable powder 7.5 kg/hm2 or 2% jinggangmycin 1.125kg／hm2 or 5% carbendazim wettable powder 1.5 kg/hm2. You can also use plant ash 225-3kg/hm2 to soak 15kg of water for a day and night, filter and spray; or use plant ash 375-525 kg/hm2 to directly spray.
third, the larvae of the rice stem fly
are milky white, which is harmful to people's hearts. After the seedling was killed, there were oval or long holes in the heart leaves, which later developed into longitudinal cracks and the leaves were broken.
control method: spray 9kg of water with 18% dimehypo 3.75kg／hm2.
fourth, rice stripe virus
is mainly transmitted by Laodelphax striatellus. Usually, the heart leaves of diseased plants show intermittent yellow-green or yellow-white short stripes along the veins, and then they are combined into large pieces, and half or most of the diseased leaves turn yellow or yellow-white. After the disease of tall stalk varieties. The heart leaves are slender, curled into paper twists, and bent and drooped to form a "false dead heart": the heart leaves are still normal after the onset of dwarf varieties. Early onset plants die, and late onset plants only have chlorosis spots on flag leaves or leaf sheaths. However, poor heading or abnormal heading is not true. The tillering of diseased plants is generally reduced.
control methods: ① select disease-resistant varieties. ② Cut off the transmission source of the virus. The first is to eliminate the virus vector Laodelphax striatellus before the disease is transmitted. Second, it is necessary to stay away from insect source fields such as wheat fields, vegetable fields and grassland wasteland, and promptly remove weeds around rice seedlings and fields to reduce the parasitism of Laodelphax striatellus. ③ Strengthen fertilizer and water management. Base fertilizer should be applied well, instead of tillering fertilizer, ear fertilizer should be applied again, and zinc, boron, manganese and other trace fertilizers or rice sensitive elements should be used during rice growth period to promote the healthy growth of rice and improve disease resistance. ④ Chemical control. Seed soaking with chemicals to prevent in advance; Before transplanting seedlings, apply a "grain delivery medicine"; If the incidence of the whole field is found to be below 3%, it should be controlled. Selection of medicament: seeds can be soaked with 5-1 times of 1% imidacloprid wettable powder or 8-1 times of 5% Ruijinte suspension. Or 5% Regent seed coating agent for seed dressing: 1% phenanthroline 3g/hm2+36% trichloroisocyanuric acid 375-45g/hm2 can be used to prevent and control; 1% imidacloprid 45-75g/hm2+3.95% Virbick 675g／hm2 can be used to treat 75kg of water in the field. The medication time should be controlled from the peak of hatching eggs of the second and third generations of Laodelphax striatellus to the peak of young nymphs.
5. Rice leaf roller
Rice leaf roller is also called leaf wrapping worm. The main migration period is generally from late May to mid-June, the spawning peak period is in mid-June, and the damage peak period is from late June to late July.
The larvae do harm. The larvae spin silk and roll rice leaves into tubes, feeding on mesophyll and forming white stripes. When the victim is serious. The rice leaves are all withered and white.
control method: the best control effect should be achieved when the larvae are in full incubation period. Generally, the third generation of annual prevention is around June 2th. It can be controlled by dimehypo (cheap treatment of borers) and dimehypo.
VI. Rice planthoppers
Rice planthoppers are commonly known as "grasshoppers". In the affected fields, rice leaves turn yellow, and tillers decrease. In severe cases, rice falls into ponds and dies. Nilaparvata lugens mainly damages from the booting stage to the mature stage. When the damage is serious, the base of rice cluster turns dark brown, and the whole plant gradually dies, and the damaged field is often "huang tang". In severe cases, the whole field is yellow and shaped like fire.
control method: the control of both planthoppers should be started when there are more than 5 plants in the field. The effective drugs are Da Gongchen, Pushiling, Yechan Powder and so on.
VII. Borrelia borealis
Borrelia borealis includes three species: Chilo suppressalis, Chilo suppressalis and Chilo suppressalis.
All three species feed on young insects. In different growth stages of rice, the damaged plants can form withered heart, withered sheath, insect-damaged plants, withered pregnant ears and white ears. Chilo suppressalis larvae are reddish brown: Chilo suppressalis larvae are dark brown with five longitudinal lines on the back: Chilo suppressalis larvae are yellowish green.
prevention and control methods: agricultural prevention and control should be given priority to, supplemented by chemical prevention and control. It is advocated to cut rice with mud, eliminate weeds along fields and ditches, and irrigate and plow green manure fields and rape fields as early as possible. Kill the worm. 25% dimehypo powder 15.-22.5 kg/hm2 can be mixed with fine soil to spread, or 25% dimehypo water agent 3.75 kg/hm2 can be used to spray 9kg of water.
eight, thrips oryzae
thrips oryzae is very small, the adults are dark brown, winged and crawling quickly. Life is divided into three stages: egg, nymph and adult. Nymphs are similar to adults, light yellow, very small, wingless, often rolled at the tip of rice leaves, sucking the juice of rice leaves. The damaged rice leaves are dehydrated and curled, the rice seedlings turn yellow, there are spots of white spots on the rice leaves, and the heart leaves shrink, which looks like a fire from a distance. Rice thrips gather when flowers are blooming.
prevention and control methods: because thrips oryzae is very small, it is not easy to attract people's attention under normal circumstances, and it is only found when rice is seriously damaged and causes a large number of leaves to roll. Therefore, it is necessary to check it in time and eliminate thrips oryzae in the larval stage. Use 15-2 times of 4% dimethoate emulsion per mu, and keep the water layer after pesticide application in seedling field and field. After the control of rice thrips, quick-acting fertilizer should be supplemented to promote the growth of seedlings and tillers.
(Author: 164351 Rural Economic and Technical Service Center, Aihui District, Heihe City, Heilongjiang Province)