The life of corn!
Popular science discusses the prevention and control strategies of ten common diseases and insect pests in corn;
Farmers remind: farmers should pay attention to the investigation and management of corn thrips!
1. corn thrips
There are two generations of parthenogenesis in maize, which is mainly caused by adults feeding on maize. In Beijing, the damage period is around mid-June, which is the wheat harvest season, so it is easy to be ignored and cause serious harm. The yellow-breasted thrips mainly harms the seedling stage, and the number of corn yellow-breasted thrips is more in the seedling stage and the heart stage, and then it gradually decreases. When spring corn and medium-mature corn have passed the heart leaf stage or the end of heart leaf stage in late June, thrips turn to summer sowing corn and sorghum at seedling stage.
morphological character
Female adults are divided into long wings, half wings and short wings. Small, dark yellow, with dark gray spots on the chest. The front wings are grayish yellow, long and narrow, and there are a few but significant veins and long hair on the wing margin. The length of the semi-long wing is only the fifth section of the abdomen at most, and the short wing is slightly bud-like in the Yangtze River Delta. Egg kidney-shaped, milky white to milky yellow. If the insect's body color is milky blue or milky yellow, there are laterally raised particles on the body surface. Pupa or pre-pupa (that is, third-instar insects) is light yellow, with white wing buds and brown pupa pieces when they emerge.
Prevention and control strategy
Agricultural control: rational close planting, timely watering, timely removal of weeds, effectively reducing the harm of thrips.
Pesticide control: When the thrips are seriously damaged, the pesticides should be sprayed in time to control them, which can be sprayed with 2000 times solution of 10% imidacloprid wettable powder, 10% nitenpyram 1500 times solution or 20% fenvalerate EC 3000 times solution.
Manual control: For "whiplike" corn seedlings, an awl can be used to plunge into the base of whiplike leaves and let them open in the middle, so that the heart leaves can resume normal growth.
2. Mucus
Corn armyworm is a migratory and food-loving pest, and it is one of the main pests in maize seedling stage at present. Myxomycetes have a variety of feeding habits, especially corn leaves, which make them form nicks. When they happen, they often eat up the leaves, leaving only bare stems, resulting in no harvest.
Dangerous characteristics
Myxomycetes have strong reproductive ability and strong selectivity of spawning sites. On tall crops such as corn and sorghum, eggs are mostly laid at the tips of dead leaves. After hatching, the larvae concentrate on the mesophyll of young leaves in the trumpet mouth, and the third-instar leaves are cut off, and the fifth-instar leaves have the largest food intake, so they can eat all the leaves. In corn, it mainly inhabits trumpet mouth, leaf axils and ear bracts. After the age of 3, there are fake deaths and self-mutilation. After the age of 4, they can migrate in groups to expand the harm. Larvae's feeding activities are most vigorous in the evening, early morning and rainy days. Adults like to feed on honey plants and have a strong tendency of black light and sweet and sour mixed wine. Myxomycetes like warm and high humidity environment. Rainfall is generally beneficial to the occurrence, but heavy rain, rainstorm and short-term low temperature are not conducive to adult oviposition. Corn fields with dense growth, low terrain and many weeds are heavy.
Prevention and control strategy
Chemical control: before the 3rd instar of armyworm larvae, 20% fenpropathrin EC 15 ~ 45g, or 5% fenpropathrin 1000~ 1500 times, or 40% omethoate 1500~2000 times.
Ecological control: Clofenuron 1~3 200× 10-6 is used in larval stage, which does not kill natural enemies, is safe for crops, uses little and does not pollute the environment. In the heyday of the appearance of armyworm, black light and sweet and sour wine were used to lure the integrated worm.
3, corn armyworm
Corn armyworm is one of the common main pests in corn crops. It belongs to LEPIDOPTERA, Noctuidae, also known as marching insects, with a body length of 17-20 mm, light grayish brown or yellowish brown, and the male moth is darker in color. Larvae overeat corn leaves, and when it is serious, it will eat up the leaves in a short time, resulting in reduced production or even no harvest. Three generations can occur in a year, and the second generation mainly harms summer corn. Natural enemies mainly include walking nails, frogs, birds, parasitic bees and parasitic flies.
morphological character
Adult body length 15- 17mm, wing spread 36-40 mm. The head and chest are grayish brown and the abdomen is dark brown. The front wings are grayish yellow, yellow or orange, which varies greatly; There are often only a few black spots on the inner horizontal line. The ring and renal line are brownish yellow, and the boundary is not significant. There is a white spot at the back end of the renal line and a black spot on each side. The lateral horizontal line is a row of black spots; The minor edge line inclines inward from the apex angle to MZ; The edge line is a row of black dots. The hind wings are dark brown and gradually fade toward the base. The egg is about 0.5mm long and hemispherical, and the primary white gradually turns yellow and shiny. Eggs are arranged in rows and blocks in a single layer. The mature larvae are 38 mm long. The head is reddish brown, the skull is reticulate, the forehead is flat, there are thick brown longitudinal stripes on both sides, slightly splayed, and there is a brown reticulation on the outside. The body color changes greatly, from light green to thick black; When it happens, the back is often black, the ventral surface is light and dirty, the midline of the back is white, the sub-dorsal line between the upper valve lines is slightly blue, and the valve lines and the lower valve lines are pink to grayish white. There is a dark brown wide longitudinal band on the outside of the abdominal foot, and a semicircular dark brown toe hook on the toe. Pupa is about19mm; Dragon; Reddish brown; There is a row of dentate points on the front edge of the back of the 5-7 abdominal segments; There are four spines on the buttock spine, two in the middle are thick, and the short spines on both sides are slightly curved.
Prevention and control strategy
For the control of adults, we should use the phototaxis and chemotaxis of armyworm adults, and adopt pollution-free control techniques such as sweet and sour solution, sex lure and insecticidal lamp to trap and kill adults, so as to reduce the amount of eggs laid by adults and reduce the population density in the field. The control time of larvae in most areas of the province is in early September, and the control target field is middle-late mature summer corn field, and the control index is the population density of 30 heads per 100 plants in corn field. During the control, 75-100g of 50% fenthion EC, 75-100g of 40% chlorpyrifos EC or 500- 1000 times of 20% diflubenzuron No.3 suspension concentrate were used, and 40 kg of water was sprayed evenly.
4. Corn borer
Corn borer, commonly known as axis worm, corn borer, etc. , belonging to Lepidoptera borer family. Corn borer is a worldwide pest, which harms more than 50 species of host/kloc-0, among which corn is the most harmful. It can cause 5- 15% yield loss every year.
Dangerous characteristics
Adult: The adult of Asian corn borer is 13- 15 mm in length, with dark brown wavy inner transverse lines and dark brown serrated outer transverse lines on the yellow (female) or yellow-brown (male) front wings.
Eggs: 20 ~ 60 eggs of corn borer are arranged in irregular scales, and the single egg is oval and flat. It is milky white (like wax drops) during production and gradually turns pale yellow, with black spots in the center before hatching (commonly known as black eggs).
Larvae: Asian corn borer larvae are 65438 0.5 mm long when they are first hatched, and the head shell is milky white and translucent. Mature larvae are 20-30mm long, with brown-black head and shell, white dirty body and obvious back hair.
Pupa: The pupa of Asian corn borer is 15- 19mm, spindle-shaped, yellow-brown, with wavy transverse wrinkles on the back, dark brown buttocks and 5-8 upward-curved bristles at the end.
Prevention and control strategy
Before overwintering larvae emerge, it is an effective measure to treat the stems of overwintering hosts such as corn, sorghum and cotton to eliminate overwintering larvae and reduce the source base of overwintering insects. In the third generation area, the sowing area of summer corn should be expanded as much as possible, the spring sowing area of host crops such as corn, sorghum and millet should be compressed, and the food source and breeding ground of 1 generation corn borer should be reduced to control the occurrence of the second and third generations and reduce the harm to summer corn.
Taking advantage of the habit that female moths like to lay eggs on tall, dense and vigorous host plants, about 1 month before the normal sowing of spring corn, we choose plots near the wintering ground to plant small areas of trapping zones and trapping fields, or strengthen the fertilizer and water management of a few early sowing spring corn fields to promote their early development and lure integrated insects to lay eggs.
Planting moth-resistant varieties is an economical, effective and safe measure to control moths. Combined with the field management measures of some crops, especially the measures of thinning seedlings, fixing seedlings, cutting cotton, harrowing and topping, the insects and eggs can be directly removed, which is more closely related to the prevention and control of corn borer. If 1 generation corn borer harms cotton seedlings, the infected plants can be removed by combining thinning seedlings with fixed seedlings; The young larvae of the second generation corn borer first harm the tender head and petiole of cotton, and then eat the stem. By pruning and topping, the damaged petioles, tender shoots and branches can be removed and taken out to the field for centralized treatment, which can obviously reduce the harm of corn borer to cotton.
Physical control: use high-pressure mercury lamp to trap insects. The specific method is to install 200W or 400W high-pressure mercury lamps in a relatively open place in the village at a distance of 150m (200m with 400W bulbs). The light bulb should be mounted on a waterproof lamp holder and fixed with iron wire. A circular pool with a diameter of lm, brick structure and cement structure can be built under the lamp. You can also dig a pit of the same size under the lamp, and lay plastic sheets in the pit, but they are all watertight. Drain the water into the pool to a depth of 6cm, add about 100g washing powder, and stir well. Generally, change water 1 time every 3 days, and add washing powder. If the water change time is not up and the water in the pool is insufficient, it can be replenished at any time. The light bulb should be hung in the center of the pool, at a distance of 15cm from the water surface. From the early stage to the late stage of overwintering adult emergence, the lights are turned on at 20:30 every day and turned off at 4:00 the next morning. Because of the large amount of moths usually attracted, the moths in the pond should be fished out and buried deeply every morning.
Biological control: Every year from mid-April to early May, before the overwintering larvae pupate, Beauveria bassiana spore powder is used to spray powder on the burned host crop straw and root stubble, and the dosage of bacterial powder is 100g/m? Spray 1 point per square meter on the stack surface until bacterial powder can be seen on the stack surface. Or in the middle period of heart leaves, 0.5 kg of Beauveria bassiana spore powder with a bacterial content of 654.38+00 billion-50 billion /g is mixed with the cinder screened by skg to make Beauveria bassiana granules with a ratio of 654.38+0: 654.38+00, and each plant is applied to the heart leaves of corn. 8000IU/mg Bacillus thuringiensis wettable powder (3kg/ mu) was mixed with 10kg fine sand to make granules, which were applied to the middle stage of corn heart leaves, and the control effect was good. Intercropping summer corn with mung bean can increase the population of parasitic bees such as Trichogramma in nature and control the occurrence of moth damage. Or multiply and release parasitic bees to control moths. In addition, the sex pheromone of corn borer can be used to trap and kill male insects or put a lot of sex pheromones, which makes it difficult for male insects to find female insects to mate. The best time to control corn borer is the end of heart leaf, that is, the big trumpet stage, which is also the key period to control corn borer.
Chemical control:
In the 2nd-3rd instar larval stage, the following chemicals can be used:
25% fenvalerate phoxim EC 80- 100ml/ mu;
20% phoxim EC 200-250ml/mu;
30% methamidophos acetate EC 125-230ml/ mu;
70-90ml/mu of 48% chlorpyrifos EC;
80% trichlorfon soluble solution 80- 100 ml/mu;
40% methyl phoxim EC 50- 100ml/ mu;
40% isocarbophos EC 75- 150ml/ mu;
40% triazophos EC 60- 100ml/ mu;
25% quinalphos EC120-150ml/mu;
20% pyridaphenthion EC 75- 100 ml/mu;
50% diazinon EC 80- 120ml/ mu;
20% phoxim EC 250-300ml/mu;
10% chlorfenapyr wettable powder100-200g/mu;
50% methylpyrimidine phosphorus EC 80- 100 ml/mu;
30% CP EC 160-200ml/ mu;
40% pyrimidinphos EC 150-300ml/ mu;
20% carbosulfan EC 200-250ml/mu;
75% thiodicarb wettable powder 60-70g/mu;
25% fenobucarb EC 200-250ml/mu;
50% cartap soluble powder 70-100g/mu;
25% carbaryl wettable powder 200-300g/mu;
2.5% cypermethrin EC 25-50ml/mu;
2.5% deltamethrin EC 20-30ml/mu;
30-40ml/mu of 5.7% cyfluthrin EC;
20% tebufenozide suspension 25-35 ml/mu;
24% methoxyfenozide suspension 20-30ml/mu;
1% emamectin benzoate EC 5- 10ml/ mu;
8000IU/ml Bacillus thuringiensis wettable powder 100-200g/ mu evenly sprayed with 40-50kg of water.
At the peak of larval stage, a bag of propafenone (8.2% tebufenozide) EC, 20 ml of water and 15 kg of herbicide were mixed in the corn field, which had no phytotoxicity.
The following agents can be used for corn heart leaves: 5% octyltriazophos granules 150-250g/ mu; 10% diazinon granules 0.4-0.6kg/mu; 1.5% phoxim granules 0.5-0.75kg/mu; 40% P EC 150-250ml/ mu; 3% carbofuran granules 2-3kg/mu; 5% carbosulfan granules 2-3kg/ mu, mixed with fine soil 15-20kg for filling.
5, locusts
Locusts are ORTHOPTERA insects of Acridoidea. Commonly known as "grasshopper", there are many kinds, with more than 10000 species in the world. Distributed in tropical and temperate grasslands and desert areas all over the world.
morphological character
The mouthparts are hard, and the front wings are narrow and tough, covering the back wings. Thin hind wings, suitable for flying, developed hind limbs and good at jumping.
Prevention and control strategy
Agricultural prevention and control: build water conservancy to ensure drought and flood; Reclaim wasteland on a large scale, change locust habitat and reduce the area of occurrence base; Planting trees, changing the microclimate in locust areas and reducing the suitable places for locust spawning and reproduction; Improve cultivation techniques to control locust eggs, adjust measures to local conditions, change crop layout and reduce locust harm.
Biological control: In locust-infested areas, agricultural and biological pesticides with high efficiency and low toxicity are used to protect predatory natural enemies in locust-infested areas. Large-scale application of microsporidia locusts.
Chemical control: When chemical agents are used to control locusts in a large area, locusts should be mastered before the age of 3. Spraying 75% malathion EC with ultra-low or low volume. Aircraft control 60 ~ 70g per mu; Ground spraying: 75g/mu, or 45% malathion ultra-low volume emulsifiable concentrate, 75-100g/mu, or 20% mixture of enemy and horse, or 1.5% lindane powder, per mu1.5-.
6. Corn aphids
Corn aphid is a pest, which can harm corn, rice and many grasses. At seedling stage, adult aphids and nymphae aphids cluster in the heart leaves, which damage the ears after heading, suck juice, hinder growth and spread a variety of Gramineae cereal viruses. Natural enemies include Harmonia axyridis, Harmonia septempunctata, Harmonia japonica, Syrphidae, Chrysopa lacewing and parasitic bees.
morphological character
Wingless parthenocarpy fruit is oval in shape, ranging from 1.8mm-2.2mm in length. Living insects are dark green, covered with thin white powder, with black appendages and reddish-brown compound eyes. The 7th section of the abdomen is black, and the 8th section has a horizontal band on the back and a net pattern on the body surface. Antennas, beaks, feet, abdominal tubes and tails are all black. The antenna has six sections, which is longer than the fuselage length of 1/3. The beak is thick and short, not reaching the basal segment of the midfoot, and the distal segment is 1.7 times the width of the basal segment. The abdominal tube is long and cylindrical, the end is contracted, and the abdominal tube is imbricated. The tail is conical with 4 to 5 hairs.
The winged parthenogenetic aphid is ovoid, with a body length of 1.6 mm to 1.8 mm, a shiny black head and chest, a yellowish red to dark green abdomen, and dark side spots in front of the abdominal tube. The antenna is 6 segments shorter than the fuselage, and its length is 65438+ 0/3 of the fuselage length. Antennas, beaks, feet, abdominal nodes, abdominal tubes and tails are black. There are 1 pairs of large marginal spots in 2-4 abdominal segments, dorsal transverse bands in 6 and 7 abdominal segments, and intermediate bands in 8 abdominal segments. Other characteristics are similar to those of wingless type. Oval.
Prevention and control strategy
Agricultural control: The cultivation mode of wheat interplanting corn is 10 ~ 15 days earlier than that of wheat sowing corn, which can avoid the peak of aphid reproduction and reduce the harm.
On the basis of prediction, according to the number of aphids, the percentage of natural enemy units in the number of aphids, climatic conditions and the occurrence of aphids were investigated to determine the types and periods of drug use.
Chemical control: The seeds were soaked with1%imidacloprid wettable powder with the weight of 0. 1%, and the control effect on aphids, thrips and planthoppers at seedling stage was excellent 25 days after sowing.
When corn entered the jointing stage, it was found that the central aphid plant could be sprayed with 0.5% dimethoate powder or 40% dimethoate EC 1500 times. When the aphid plant rate reaches 30% to 40% and "oil plants" (honey dew) appear, the whole field should be treated. Sprinkle Xerox poison sand first, dilute it with 500L of water in 50g of 40% dimethoate emulsifiable concentrate every 667 square meters, spray it on 20kg of fine sand, stir it while spraying, and then spread it evenly on the plants. You can also spray 1000 times of 25% Acax or 50% phoxim EC at a dosage of 509 per 667 square meters or spray 1.5% 1605 powder at a dosage of 2 to 3 kilograms per 667 square meters.
Fill the heart with carbofuran. At the end of the big horn of corn, every 667 square meters, use 1.5kg of 3% carbofuran granules, and pour the corn heart evenly. If you are afraid of uneven pouring, you can mix 2 to 3 kilograms of fine sand into carbofuran and stir it evenly.
10% imidacloprid wettable powder 2000 times, 10% saibaokai emulsifiable concentrate 2500 times, 2.5% Baode emulsifiable concentrate 2000-3000 times and 20% Kangfuduo concentrated soluble solvent 3000-4000 times.
7. Spodoptera exigua
Spodoptera exigua, whose scientific name is Spodoptera exigua, belongs to Lepidoptera and Noctuidae. It is an omnivorous pest that mainly harms vegetables and occurs intermittently all over the world. Harm green onion, cabbage, Chinese cabbage, celery, cauliflower, carrot, asparagus, spinach, amaranth, pepper, cowpea, cauliflower, eggplant, kale, tomato, Chinese cabbage, broccoli, spinach, radish and other vegetables.
morphological character
The body color of larvae varies greatly, such as green, dark green, brown, dark brown and so on. The lower line of the ventral lateral valve is obviously yellow-white longitudinal band, sometimes pink. Adults lie down during the day and come out at night, with strong phototaxis and weak chemotaxis. Older larvae have suspended animation, and mature larvae spin silks underground to pupate.
Prevention and control strategy
Agricultural control: pupating in cultivated land in late autumn and early winter; Manually remove egg pieces and insect leaves.
Physical control: black light traps and kills adults.
Chemical control:
To catch 1~2 instar larvae for control, the following chemicals can be selected for spraying:
5% chlorhexidine EC 4000 times solution
Or 4,000 times of 5% carbendazim EC.
It is still 4000 times that of 5% Nong Mengte EC.
Or 500- 1000 times of 20% diflubenzuron suspension.
Or 500- 1000 times of 25% diflubenzuron No.3 suspension.
Or 2000-3000 times of 40% Juma EC.
Or 2000-3000 times of 40% Juma EC.
Or 20% fenvalerate 2000-4000 times solution.
Or 500 times of anisodamine pesticide solution.
8, corn spider mite
Corn Tetranychus urticae is a red spider, belonging to Arachnoidea and Tetranychidae, and it is a polyphagous pest. Nymphs or adults suck juice on the back of leaves, causing the leaves to die and affecting the yield.
morphological character
The body color of adult mites changes with the seasons, generally red or rust red, and the female mites are round and about 0.55 mm long. The male worm is oval. Young mites are nearly round, transparent in color, with red eyes and three pairs of feet. After feeding, their bodies turn dark green. If a mite has four pairs of feet, its body becomes dark and obvious block pigments appear on its sides.
Prevention and control strategy
According to the biological habits of jujube spiders, agricultural, physical and chemical control measures can be taken.
Artificial control: scrape bark and burn it centrally before the overwintering eggs hatch. After scraping, paint white (limewater) on the trunk to kill most of the overwintering eggs.
Agricultural control: according to the hatching law of overwintering eggs and the habit of feeding and breeding on weeds first after hatching, the red spider was turned over in early spring to remove weeds on the ground and keep the field free of weeds during the incubation period, so that the red spider died because it could not find food.
Physical control: Before the jujube tree germinates and the jujube red spider is about to harm the tree (about late April), a closed adhesive ring with a width of about 1 cm can be applied to the trunk to prevent the jujube red spider from moving to the tree, and the effect can reach more than 95%.
Biological control: There are many kinds of jujube red spiders in the field. According to the investigation, there are mainly Chrysopa sinica, mite-eating ladybug and predatory mites, among which Chrysopa sinica has a large population and a large predation on jujube red spider. Protecting and increasing the number of natural enemies can enhance its control of jujube red spider.
Chemical control: 1000~ 1500 times of 40% dicofol EC, 2000 times of 20% Migujing WP, 2000 times of 15% pyridaben EC and 1.8% avermectin EC can be used.
When damaged plants are found in the field, 1 ~3 leaves with mites (eggs) should be pulled out in time to control mite damage. The picked leaves shall be bagged and buried deeply or burned, and shall not be used as feed or human manure pile.
9. Spodoptera litura
Lepidoptera Noctuidae is a new pest in summer corn area of China, which is often mistaken for the harm of cutworms everywhere. With the growth of larvae, the food intake of pests will continue to increase, and the occurrence range will be further expanded. If it is not controlled in time, it will seriously threaten corn production. Therefore, it is necessary to strengthen the monitoring of the occurrence dynamics of Spodoptera litura, do a good job in forecasting or early warning the insect situation, guide farmers to prevent and control it in time, and reduce its damage losses.
morphological character
Morphology of pupa and egg: the pupa is about 10 mm long, and it is yellow-brown at the initial stage of pupation and gradually turns brown. Egg-shaped steamed bread with longitudinal ridges, yellow-green at the beginning and yellow at the back. Less than one millimeter in diameter; Egg yield per unit area is based on wheat straw. A female moth can lay hundreds of eggs.
Larvae morphology: the mature larvae are 14~ 18 mm in length, up to 20 mm in length, yellow-black to dark brown, with brown head.
Morphology of mature larvae: forehead is dark brown, forehead is yellow, and forehead seam is yellowish brown. There are two brown back lines on the back of abdomen, which disappear to the chest, and there is an inverted triangle dark brown stripe on the front edge of each back. The valve is black, the upper line of the valve is dark brown and the lower line of the valve is white. Smooth body surface. Fake death, curled up in a c shape after being scared.
Adult morphology: The adult of Spodoptera litura is 10— 12mm in length, grayish brown, with dark gray front wings with 1 white spots and black spots on it. The hind wings are silver-gray and shiny.
Prevention and control strategy
Agricultural prevention and control: sowing corn after stubble removal by using stubble remover or shallow rotary tillage before sowing after wheat harvest can effectively reduce the harm of Spodoptera litura and improve the sowing quality of corn, which can be planted in Miao Zhuang; Carry out manual weeding and chemical weeding in time, remove wheat stubble and wheat straw stubble, and reduce the environmental conditions for pest breeding; Improve sowing quality, cultivate strong seedlings and improve pest resistance.
Chemical control: The best time to control larvae before the third instar is before emergence (both before and after sowing).
Poison bait spreading: 4-500g of fried wheat bran or crushed fried cottonseed cake per mu is mixed with 90% crystal trichlorfon or 48% chlorpyrifos emulsifiable solution to prepare poison bait, and then it is spread along the ridge of corn seedlings in the evening, and toxic soil is spread. 300 ~ 500ml of 80% dichlorvos emulsifiable concentrate mixed with 25kg of fine soil was spread on the ridge of corn seedlings in the morning, and the control effect was good.
Irrigation, (65,438+0) water, 48% chlorpyrifos EC 65,438+0 kg/mu when watering the field. (2) Spraying corn seedlings, you can unscrew the nozzle and drop the liquid medicine one by one along the stem, or spray the roots with a straight nozzle. The chemical agent can be 48% chlorpyrifos EC 1500 times solution, 30% acephate EC 1000 times solution, 2.5% beta-cypermethrin EC 2500 times solution or 4.5% beta-cypermethrin. The amount of liquid medicine should be large to ensure that it penetrates into the hiding place of pests around the root of corn about 30cm.
10, Laodelphax striatellus
Laodelphax striatellus is a member of Laodelphax family, belonging to Laodelphax genus, which is mainly distributed in Hainan Island in the south, Heilongjiang Province in the north, Taiwan Province Province in the east and coastal areas in the east, and Xinjiang in the west, especially in the middle and lower reaches of the Yangtze River and North China. Because the host is rice, wheat, corn, barnyard grass and other lawn grasses and gramineous plants, it is very harmful to agriculture.
morphological character
Adults: 3.5 mm for males and 4.0 mm for females; Short-winged males are 2.3 mm, females are 2.5 mm, and the yellow females on the top of the head and chest backboard are light yellow in the middle and dark brown on both sides. The front wings are almost transparent and have wing spots. The male insects on the ventral surface of the chest and abdomen are dark brown, the female insects are yellowish brown and the feet are light brown. Egg: oval, slightly curved, long 1.0 mm, with the front end thinner than the back end, initially milky white and later yellowish.
Nymphs: 5 instars in total.
1 instar nymph length 1.0- 1. 1 mm, milky white to light yellow, with a longitudinal white part along the middle of the back of each thoracic segment.
The body length of the 2nd instar is 1. 1- 1.3mm, alternating with yellow and white, and the back of each thoracic segment is gray, and the white part in the middle and longitudinal direction is more obvious than that of 1 age.
The body length of the 3rd instar is 1.5 mm, which is grayish brown, the back of each thoracic segment is gray and thickened, the white part in the center of the midline is not obvious, and the front and rear wing buds begin to appear.
Body length of 4th instar 1.9-2. 1mm, taupe. The anterior pterygoid bud reaches the abdominal segment 1, the posterior pterygoid bud reaches the abdominal segment 3, and the white part in the middle of the chest disappears.
The 5th instar is 2.7-3.0mm long and grayish brown. The middle pectoral pterygoid bud reaches the third posterior margin of abdomen and covers the posterior pterygoid bud, and the posterior pectoral pterygoid bud reaches the second abdominal segment, with obvious boundary between abdominal segments and thin white ring between abdominal segments. If an insect overwinters, its body color is dark.
Prevention and control strategy
Agricultural control: select insect-resistant (resistant) rice varieties, carry out scientific fertilizer and water management, and create ecological conditions that are not conducive to the reproduction of white-backed planthopper.
Biological control: There are many kinds of parasitic and predatory natural enemies of white-backed planthopper. Besides parasitic bees, midges, ladybugs, spiders, nematodes and fungi have great inhibitory effects on the occurrence of white-backed lice. Protecting and utilizing natural enemies can obviously control the occurrence and harm of white-backed planthopper.
Chemical control: according to the type of rice varieties and the occurrence of rice planthopper, the control measures should focus on the prevention and control of juvenile nymphs of the main pest generation in the peak period. If the migration of adults is particularly large and concentrated in the current year and region, the control measures should be combined with the young nymphs of the main pest generation in the peak period.
Chemical control: 70% imidacloprid, 20% pymetrozine, 0.5% veratrine wettable powder, 90% dichlorvos and other conventional control.