Rice leafhopper is an important pest on rice, generally less occurrence, in some areas in some years will occur largely, to adults and nymphs in the lower part of the rice stalk, leaves to suck sap, seriously causing rice plants to die or appear "black spike", white panicle phenomenon, but also can spread rice common dwarf disease, yellow dwarf disease and other viruses. Rice leafhoppers occur in all rice areas, and the leafhoppers that are more harmful in the middle and lower reaches of the Yangtze River are black-tailed leafhoppers, white-winged leafhoppers and electro-light leafhoppers, among which black-tailed leafhoppers and electro-light leafhoppers can transmit dwarf viruses.
Black-tailed leafhopper
<h1>1. Symptoms of rice leafhopper harm</h1>
Black-tailed leafhoppers become nymphs hiding in the lower part of the rice plant stalk, eating on the upper leaves of the rice plant in the morning and evening, the damaged rice seedlings have yellowed leaves, and white stripes or tan stripes appear in the victims; the white-winged leafhoppers are prickly on the leaves, and the affected leaves are initially white spots, and then become brown spots; the electric leafhopper mainly feeds on the leaves and leaf sheaths, causing the victim rice plants to grow slowly, the leaves are yellow, and there are no white spots at the victims. When the rice leafhopper is seriously harmful, the rice leaves dry up and the rice plants wither.
If it is harmful at the panicle stage, the excrement of the rice leafhopper in the rice ear is contaminated by mold, so that the surface of the rice panicle will produce a black mold layer, resulting in the symptom of "black spike"; if the damage is serious during the filling stage, a semi-white panicle is formed, and the grain is empty.
<h1>2. Characteristics of rice leafhoppers spreading rice dwarf virus</h1>
Rice dwarf virus mainly takes leafhoppers and rice as the host, poisonous leafhoppers will be infected with viral diseases in rice after eating rice, if there is no poisonous leafhopper because of eating diseased rice, and then eat healthy rice for transmission, and the proportion of virus transmission through eggs is very high. Therefore, the damage caused by the spread of the virus by rice leafhoppers is far greater than the harm caused by feeding and spawning.
Rice dwarf disease
<h1>3. Identification points of rice leafhoppers</h1>
Black-tailed leafhopper: Adults have a black transverse band on the anterior margin of the head of the head, and 1/3 of the end of the forewing is black or light brown. The nymphs are yellowish-white to yellowish-green , with an inverted " figure eight " brown stripe on the top of the head and on the back of the middle and back of the thorax.
Electric leafhopper: Adult stony gray with a brown lightning-like stripe on the wing surface, older nymph yellow-green, red thorax, upturned tail tip.
Electric leafhopper
White-winged leafhopper: yellow-orange head and thorax, translucent forewing membranes, covered with white waxy and rainbow; dark brown on the back of the abdomen, yellow on the ventral surface and feet. The older carers are pale yellowish-green, translucent, with purple-brown compound eyes and long hairs on the back of the body.
<h1>4. Occurrence law</h1>
Rice leafhoppers mostly overwinter on grassy weeds such as green manure fields and field mounds, and migrate to early rice seedlings or honda fields the following year. Black-tailed leafhoppers can occur 5-7 generations a year in Hunan, Jiangxi, Hubei and other places, electric leafhoppers can breed 5-6 generations a year, and white-winged leafhoppers can occur in 3 generations, and there will be generation overlap. Adults have phototropism and tenderness, can fly and jump, and will quickly avoid when frightened. In the 2-3 leaf stage of seedlings and the return to greening stage of the field, it is the most vulnerable and critical period for the transmission of the virus; glutinous rice and japonica rice are more vulnerable than indica rice, and the occurrence of partial nitrogen fertilizer, over-dense planting, and mixed planting areas of early, middle and late rice is large.
White-winged leafhopper
The black-tailed leafhopper has the largest number from mid-July to late August, which coincides with early rice harvesting and late rice transplanting, so double-cropping late rice is more seriously affected by black-tailed leafhoppers and viral diseases; white-winged leafhoppers suffer more from double-cropping late rice, followed by late planting of single-season late rice; electric leafhoppers are the most harmful in the rice areas of the middle and lower reaches of the Yangtze River from September to November.
<h1>5. Prevention and control methods</h1>
(1) Agricultural measures: eradicate weeds in the field and on the field, reduce the source of insects; rational dense planting, avoid partial application of nitrogen fertilizer, and prevent rice from being greedy and growing.
(2) Pharmaceutical control: Thiamethoxine, imidacloprid, pyrazone, furazine, pyridone, isopropylvir, aladine pyridone and other agents can be selected, and their control methods are the same as the control of rice planthoppers. During the critical period of prevention and control, the seedlings are mainly grasped at the 2-3 leaf stage and 2-3 days before transplanting, and then sprayed again during the peak tillering period, which can be combined with other insecticides and fungicides; rice growth in the middle and late stages of field has more than 300 heads for prevention and control. Keep a 3-5 cm water layer in the field during application and retain water for 3-4 days.
(3) Booby-trap adults: Adult insecticidal lamps can be used to trap adult insects during the peak period.
(4) Prevention and control points: summer sunny and hot, drought and little rain are conducive to the occurrence, pay attention to the mixing of antiviral disease agents when taking drugs, such as adding 8% niyramycin water agent 50-60 ml / mu or 30% toxic phosphorus wettable powder 15 g / mu.
Special reminder: in the middle and late rice fields are more focused on the use of drugs to control rice planthoppers, in general, rice growth in the middle and late stages rarely appear a large number of rice leafhoppers, but rice seedlings and tillering stage is to pay attention to the use of drugs to control rice leafhoppers, rice planthoppers and virus disease prevention agents.
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