China's corn production is widely distributed, and it is planted in many provinces, municipalities and autonomous regions across the country. In recent years, farmers have generally promoted new cultivation techniques such as no-tillage and straw returning. With the increase of corn area and the replacement of corn varieties, new changes have occurred in corn pests and diseases. We invited Wang Zhenying from the Institute of Plant Protection of the Chinese Academy of Agricultural Sciences to pay attention to the prevention and control of important insect pests in China.
What is a corn thrips?
Wang Zhenying: The thrips that harm China's corn are mainly corn-yellow-staple horses, scorpion horses, and rice-tube hummers, all of which belong to the order Thysanoptera. The first two belong to the genus Pteropidae, and the rice dams belong to the genus Marco. Corn stalks are also known as corn sorghum horses, grass scorpions, and domestically distributed in North China, Xinjiang, Gansu, Ningxia, Jiangsu, Sichuan, Tibet, Taiwan, etc., which can harm corn, broad beans, bitter vegetables, millet, Gramineous crops such as sorghum, rice and wheat.
Hessian horses, such as Hehuahuama, Hewake Hummer, and Slimming Hummer, occur in most parts of the country and can harm grasses, rice, wheat, sorghum, scorpion and other gramineous plants and spinach, eggplant, and melon. Wait. Rice straw thrips, alias Huma, Hegu and Huma, are distributed throughout the Northeast, North China, Northwest, Yangtze River and South China provinces. The corn thrips are mainly harmful in the summer maize area of ​​Huanghuaihai, and have become the main pests of summer maize seedlings in this area.
What are the main symptoms of the damaged corn?
Wang Zhenying: Corn thrips use adult insects and nymphs to suck the sap of young corn, causing serious damage to corn. The affected plants are generally twisted into "hip whip", growth is stagnant, germination of buds in severe cases, and even corn destruction.
The yellow-streaked thrips mainly cause serious damage to the corn by adult insects. Intermittent silver-white streaks appear on the back of the infected leaves, accompanied by small stains (ie, worms). The leaves on the front of the leaves are yellow and the leaves are severely damaged. The back is coated with a layer of silver powder, and the end half turns yellow and dry. Wo Yi Ma Yicheng, nymphs in the corn heart leaf activity hazard, mostly occurred before and after the big horn period, can also be harmful in front of the stretched leaves, resulting in leaves appearing silver-gray spots.
Morphological characteristics of corn thrips
Wang Zhenying: 1. Corn yellow horses
Adults have polymorphisms, which are divided into long-winged, semi-long-winged and short-winged, with long-winged most, but also a small number of short-winged and very few semi-long-winged. The long-winged female adult has a body length of 1.0 mm to 1.2 mm, and the yellow color is slightly dark. The chest and belly back (except for the number of ends) have dark areas. The tentacles are 8 knots, the first section is yellowish, the second to fourth sections are yellow, gradually blackened, the fifth to eighth sections are grayish black, the third and fourth sections have forked cones, and the sixth section has light and bright oblique seams. (also known as the pseudo-section).
There is no long squat on the head and front chest. The fore wing is yellowish, long and narrow, and the anterior vein is intermittent. The vast majority have 2 end sputum, a few, the venous sputum is weak, the margin is long, and the winged thoracic section is significantly wider than the front chest. Each eight-section of the back of the abdomen has a complete comb, and the abdomen is long and dark. The semi-long-winged front wings are up to the fifth quarter of the abdomen. The short-winged front wings are short, degenerate into triangular buds, and the winged chest is barely wider than the front chest. No reports of males have been reported.
The egg is about 0.3 mm long and about 0.13 mm wide. It is kidney-shaped and milky to creamy yellow.
The newly hatched nymph is as small as the needle tip, and the head and chest occupy a large proportion of the body, and the tentacles are relatively short and thick. After the second age, it is milky or milky yellow with gray markings. The ends of the antennae are grayed out. The body is very short, only the ninth and tenth belly are longer. On the ninth abdominal section, there are 4 meridians with a slightly nodular shape.
Forehead (3rd instar) Head, chest, and abdomen are yellowish, tentacles, wing buds and feet are pale, and complex eyes are red. The antennae segmentation is not obvious, slightly sheathed and stretched forward. The body is short and pointed, and the eighth abdominal segment is longer. There are 4 curved teeth on the back of the ninth abdominal section.
蛹 (4 years old) The antennae are placed on the head and back to the front chest. The wing buds are longer and brown when approaching feathering.
2. Wo Ma
Adult female body length is 1.3mm~1.5mm, body gray brown to dark brown, chest slightly shallow, 3~8 knot front edge is darker; tentacles 8 knots, dark brown, only third, fourth yellow, each A fork-shaped sensation cone; the top of the leg section and all the tarsus, the sacral yellow to yellowish brown; the wings are pale yellow; The head is larger than the width, slightly longer than the front chest, the cheeks are parallel, the top of the head is slightly convex, and the inner edges of the single eyes are dark;
It is long between the eyes and is born on the outer edge of the triangle. The front chest plate is smoother and wider than the length. There are 5 pairs of long scorpions in the front chest, the anterior horn is longer than the leading edge, and the trailing edge has 1 pair of short scorpions. The anterior wing veins are continuous and uniform, with 18~20 anterior veins and 14~15 posterior veins. The back edge of the eighth abdominal section is incomplete. Male adult worms are similar in shape to female adults, but small and narrow, with a body length of about 0.9 mm, body color grayish yellow, feet and tentacles yellow, and abdominal 3~7 webs have dumbbell-like glands.
The egg is about 0.3 mm long and about 0.12 mm wide. It is kidney-shaped and creamy yellow.
The nymph is like an adult, gray-yellow, wingless, with micro-hairs on the third and fourth quarters. The ends of the body are tipped at a total of 4 years old.
Life habits of corn thrips
Wang Zhenying: Adults of corn stalks are overwintering in the roots and dead leaves of grassy weeds. The number of generations is still unclear. In Shandong Province, in the middle and late May of each year, from the gramineous plants to the spring sowing corn, breeding on spring maize for 2 generations, the first generation of nymphs occurred in spring maize or wheat crops from late May to early June, mid-June Entering the adult germination period, June 20 is the peak of the egg, and the second is the nymph, and the adult occurs in the summer corn in early July. Adults are slow and inactive, especially in rainy days. They are also unwilling to take off after being shocked.
The adult is parthenogenetic, and the feeding place is where it lays eggs. The egg is produced in the leaf tissue, the egg back is bulged out of the leaf surface, brightened, and the egg leaf is removed. The eye and the egg shell are visible to the light and the egg shell is a small white point with a dense needle tip.
The newly hatched nymph is milky white. Nymphs are only one or two nymphs, and gradually become milky or milky yellow after feeding. The third and fourth instars stopped feeding, which were called the front scorpion and the scorpion, respectively, hidden in the leaf sheath at the base of the plant, in the dead leaves or falling into the loose soil. Most of the turmeric horses are concentrated on the bottom 2~6 leaves, and rarely migrate to the newly stretched leaves.
Generally, the amount of insects on spring corn is high, but it is lightly damaged due to large plants and thick leaves. However, although the amount of single insects on the medium-sized corn is less than that of spring maize, the damage is relatively serious due to small plants and thin leaves. The insect has the habit of transferring the main hazard, and the transfer of corn to the host during the flood season before and after the flooding of the corn is roughly divided into three stages:
- In the first stage, the transfer from the insect source base wheat to the spring sowing corn;
- In the second stage, the spring sowing of corn and wheat together became a source of insects and transferred to hosts such as late spring maize, which is the peak of damage on corn;
- In the third stage, it was transferred from late-season spring corn to hosts such as summer-sown corn. In corn, the number of seedlings and trumpets was the largest, and the number decreased during this period, but the corn seedlings suffered serious, so it was mainly corn seedling pests. The most embarrassing year was mid-June.
The habits of the wolf horse
Wang Zhenying: The adult worms of the worms are wintering in the bases and dead leaves of the grass weeds. Cheng and nymphs are more active, and it is easy to be confused with corn stalks in the field. However, it is smaller and more lively than corn stalks. It likes to hide the environment, prefers to grow on vigorous plants, and is more active in heart leaves. In the middle, the occurrence period is slightly later than that of the yellow horse. It occurs mostly before and after the bell mouth period, which is related to the like to feed in the bell mouth.
When eating the heart leaves, the silver-gray spots are not obvious. When the leaves are scattered, they are also feeding on the front side, and the leaves appear as silver-gray spots. There are many adults, and there are few nymphs. The main damage to corn is adult.
Generally, female adults are more than males. In the suburbs of Beijing, female adults accounted for 73% of wheat in late May and mid-June, and female adults accounted for 82% of spring maize and medium corn. In the Beijing area, the number of occurrences was large in the middle and late June, but after a large rainfall, the number often declined rapidly.
What is the relationship between the occurrence of corn thrips and the climatic environment?
Wang Zhenying: The occurrence of corn and thrips in the year is closely related to the damage and rainfall, and has little to do with temperature. Drought is beneficial to the occurrence of corn thrips, rainfall has a greater inhibitory effect on the population, and can also promote corn growth, and its good compensation can reduce the damage.
The occurrence of corn thrips is related to the microclimate in the field. In the wheat-covered corn fields, the environment of the ditch, road and canal is relatively ventilated and dry, the amount of corn thrips is large, and the ridges are more damp and humid. It is small. Weeds are the middle host of the Hummer, the weeds are more fields, or the corn near the weeds on the ground. The amount of insects is large and the damage is heavy.
How to prevent corn thrips?
Wang Zhenying: 1. Agricultural control
Combined with wheat cultivating and weeding, winter and spring try to remove weeds in the field and reduce the number of wintering insect populations. Strengthen field management, promote the growth of plants themselves, improve the ecological conditions in the field, reduce the harm, and twist the tops of the seedlings that are rolled into a "bull tail" shape, which can promote the extraction of heart leaves, timely irrigation and fertilization, strengthen management, and promote The corn seedlings grow early and long, pass through the seedling stage, reduce the harm, and also change the microclimate of the corn field and increase the humidity, which is not conducive to the occurrence of the thrips.
The timely removal and destruction of the residual strain of the damaged corn during the occurrence of the thrips can alleviate the spread of thrips. Rotation can reduce the damage of corn thrips. Cultivation at the right time, avoiding the peak period, using resistant varieties, the dentate type is more resistant to insects than the hard type. Because the corn is weakened by the thrips, the seedlings can be added to the spray and the potassium dihydrogen phosphate foliar fertilizer to promote the growth of the corn.
2. Chemical control
Chemical control is an effective measure to control corn thrips. The rate of corn thrips is 40% to 80%, and the number of insects is 300 to 800. Field trials have shown that organophosphorus and carbamate have better control effects on thrips. 40% omethoate emulsifiable concentrate 1 000 times solution, 40% chlorpyrifos emulsifiable concentrate 1 000 times solution, 10% imidacloprid WP 2 000 times solution, the control effect is above 85%.
60% imidacloprid suspension seed dressing seed dressing, the control effect can reach more than 90%, and the seedling rate is increased by about 7%. In combination with the control of Laodelphax striatellus, the use of nitenpyram, acetamiprid, pymetrozine and other drugs has a good control effect on thrips.
Because thrips are mainly concentrated in the heart of corn, it is important to note that the drug should be sprayed into the corn heart. The field and indoor efficacy test proves that the veterinary vinegar is not effective against the thrips, and sometimes it may have an attractive effect on the thrips. Therefore, the use of veterinary veterinary pesticides should be avoided.
The occurrence of corn thrips has the characteristics of serious overlap, large amount of insects and heavy damage, and the worms are small. The newly hatched nymphs are as small as the tip of the needle. The hazard of the activity is very hidden and not noticed. The masses sometimes think it is a seed. Due to quality problems, disputes should be given due attention.
This article URL: corn hummer pictures how to prevent corn hummer
Vet Ultrasound Scanner,Ultrasound Scanner For Vet,Ultrasound Scanner For Horse,Animals Ultrasound Scanner
Guangzhou Sonostar Technologies Co., Limited , https://www.sonoeye.com