There are four main types of leaf miner commonly found in vegetable production: Liriomyza sativae, Liriomyza huidobrensis, tomato leafminer, and pea leaf miner. The common feature of their harm is that the larvae sneak into the leaves to feed on the mesophyll, but the hazard is the pea leaf miner. 1. Hazard identification 1.1 Liriomyza sativae: Adults and larvae can be harmful. Adults feed on the front of the leaves and lay eggs. The larvae sneak into the leaves and petiole from the front of the leaves, producing irregular serpentine white worms. The chlorophyll is destroyed, affecting photosynthesis, and the damaged leaves are shed, causing flower buds and fruit to be burned. Affect the yield of vegetables, and when it is serious, the plants will die. In the early stage of Liriomyza sativae, the insect tract was stretched in an irregular line, and the terminal of the worm was significantly wider than that of the larvae. 1.2 Liriomyza huidobrensis: Adults use the ovipositor to produce eggs in the leaves. The hatched larvae sneak into the mesophyll between the leaves and the epidermis, eating the ribs and veins, and the leaves become transparent plaques, causing the seedlings to die. It is extremely destructive. The larvae often form a submerged tract along the veins, and the larvae also feed on the sponge tissue in the lower layer of the leaves. The stalks are often incomplete from the leaf surface, which is different from the Liriomyza sativae. 1.3 Tomato leafminer: Adults feed and lay eggs on the front of the leaves, stab the leaf cells, and the larvae sneak into the mesophyll after hatching, which is a tortuous mark. The seedlings are more affected by 2~7 leaves. Severe latent marks are densely formed, forming a curved meandering on the leaves, destroying the normal tissues of the leaves, affecting the photosynthesis of the plants, and causing the leaves to fall off and the plants to prematurely deteriorate in severe cases, which has adverse effects on crop production and vegetable cultivation. 1.4 pea leaf miner: The larvae sneak into the leaf in the leaves, causing the spiral shape to bend the stalk, causing the leaves to wither. The latent leaves of the larvae of the beet leaf miner are harmful, and the latent marks are wide, leaving the epidermis of the leaves to be translucent blister. When the larvae of the larvae have a leaf, they are easy to make the leaves wither. 2. The occurrence of pea leaf miner 4 to 18 generations occur in one year, overlapping generations. In the area to the north of the Huaihe River, the wintering of the locusts in the affected leaves, the south of the Huaihe River to the south of the Yangtze River is dominated by wintering, and a few larvae and adults can also survive winter. The southern part of China can occur continuously in winter, and the number of insects gradually increases from early spring. Rising, it is harmful in the late spring and early summer. The insect is not resistant to high temperatures, above 35 °C, the natural mortality rate is high, the activity is weakened, and even the summer is over, and the fall begins again. Adults are active during the day, sucking nectar, flying, crawling, and chemotaxis. The pea leaf miner has strong cold tolerance and is not resistant to high temperature. If the temperature is above 35 °C in summer, it cannot survive or surpass the summer. Therefore, it is generally the most serious in the late spring and early summer, the summer is lightened, and the damage in the southern autumn is aggravated. From north to south, the spring hazard is obviously increasing, and in autumn it is the opposite. Adult pea leaf miner is active, active during the day, sucking molasses and leaf juice for supplementary nutrition. Quiet and concealed at night, but can still crawl and fly on sunny days or light rainy nights with temperatures of 15 to 20 °C. The egg is produced on the young leaves, and the position is mostly on the edge of the leaf back. When laying eggs, the ovipositor first punctures the lower back of the leaf back, and then produces 1 egg at the stab, and the leaf surface of the spawn is grayish white. . Since the female puncture tissue does not necessarily lay eggs, the oviposition on the leaves is often more than the actual number of eggs laid. Adults have a life span of 7 to 20 days, 4 to 10 days when the temperature is high, and 1 to 3 days before the adult spawning. Each female can lay more than 50 to 100 eggs in a lifetime. The egg period is about 9 days in spring and 4 to 5 days in summer. After the larva hatches, it feeds inward from the leaf edge, passes through the soft tissue, reaches the palisade tissue, and feeds the mesophyll to leave the upper epidermis, causing a gray-white curved tunnel, and as the larva grows, the tunnel circling and stretching gradually widens. The larvae are 3 years old, and the mature larvae are paralyzed at the end of the tunnel. The pea leaf miner occurs 8-10 generations a year in northern Jiangsu. It winters on rapeseed or peas. It begins to harm on rapeseed at the end of February and early March. Adults begin to occur in broad beans from mid-March to early April. The hazards on vegetables are the most serious larvae from mid-April to mid-May. From June to August, the temperature hazard has decreased, and the temperature drop will increase from September to October. In November, the damage will be reduced as the temperature drops, and the winter will be reduced. When the phlegm is removed, the end of the tunnel is bitten, so that the front valve of the sputum communicates with the outside world, and the emergence of the worm is facilitated. Due to this habit, spraying in the flood season also has a certain effect. The pea leaf miner prefers to choose tall and dense plants to lay eggs, so the densely growing plots are more seriously damaged. 3. Harmful habits are pea leaf miners, which can be used for lettuce, peas, kidney beans, kidney beans, cabbage, rape, radish, cabbage, broccoli, potatoes, eggplant, tomato, onion, garlic, celery, sage, etc. vegetables. The main performance is that the larva sneaked into the epidermis of the host leaf, twisting through the line, feeding on the green tissue, resulting in an irregular gray-white linear tunnel. When the hazard is serious, the leaf tissue is almost completely damaged, and the leaves are covered with rumps and even withered. Adults can also absorb plant juices and make them suck into small white spots. The larvae sneak into the upper and lower leaves of the leaves to feed on the mesophyll, which is twisted and passed through to form an irregular gray-white linear tunnel with fine worms. When the damage is serious, the whole leaves are covered with insects, and the leaves gradually lose their green parts and become white, which seriously affects photosynthesis, causing the leaves to fall off early, especially the leaves at the base of the plants are most seriously damaged. The larvae also feed on tender stems, pedicels and tender horns. The rapeseed and vegetable flowering period is rich in honey. The adult eggs have a large amount of eggs, and the number of larvae in the knot stage increases sharply. The number of larvae in the pod-expanding period and the degree of damage reach the highest peak. 4. Characteristics of the damage: The leaf miner is one of the important pests on the vegetables in Tongzhou District. There are many species, among which pea leaf miner and Liriomyza sativa are dominant populations. The leaf miner has a wide range of hosts and can be eaten on more than 20 kinds of vegetables and rapeseed crops such as peas, chrysanthemum, eggplant, green vegetables and peas. Adults poke the leaf epidermis to lay eggs, and the larvae feed on the leaves in the leaves to form a twisted and wormy path, which affects the photosynthesis of the leaves, reduces the yield and quality of the vegetables, and can reduce the yield by more than 50%. 5. Current occurrence of vegetable leaf miner: The pea leaf miner is mainly caused by spring open-air vegetables, and the peak period occurs from late April to mid-May. As the temperature increases, the degree of damage increases. Liriomyza sativae: It occurs later than the pea leaf miner in the whole year. The victimization rate of the host vegetables in the period from April to May is gradually increasing. The peak period of damage is in May and June, and it is more harmful in greenhouse vegetables. According to the pea leaf mites system, this year's pea leaf mites began to appear earlier than last year. At the end of March, there were worms in the lower leaves. The leaf damage rate was 5.2%, and the phyllox road was 7.33. The hazard rate increased to 12.4%, and the variegated egg was 26.2. The degree of damage was significantly higher than that before 7 days, but the insects were still limited to the lowest 2-3 leaves. I conducted a census on April 14-15. The greenhouse vegetables mainly investigated 10 sheds of tomato, 8 sheds of small green vegetables, and 8 sheds of green pepper. In the greenhouse vegetables, only the leaf miners were found on the eggplant, and the leaf damage rate 0-14%, an average of 2.38%, 0-20 of venetian tract, an average of 3.3, and a volume of 0-2.5 blinds, an average of 0.31. 10 pieces of peas and 8 pieces of cabbage were investigated on open-air vegetables. Only a few fields on the cabbage had scattered insects in the lower leaves. The leaf damage rate was 0-1.22%, with an average of 0.18%, and the volume of variegata was 0-1.22, with an average of 0.18. head. It is more common in peas, especially early peas. In the survey, the worm field blocks accounted for 90% of the investigated plots, the leaf damage rate was 0-52.2%, the average was 37.1%, and the variegated volume was 0-662 heads. 133.8 heads. Vegetable leaf miner will have a tendency to increase in the near future, especially the pea leaf miner. If it is not controlled, it will cause damage to the whole plant, which will eventually cause premature pea dying and die early. 6. Prevention and control methods: With the increase of temperature, the host range of the leaf miner will continue to expand, and the degree of occurrence will gradually increase. Therefore, the towns should guide the vegetable growers to pay attention to the occurrence of the insects and do a good job of prevention and treatment. First, timely remove the old leaves and foot leaves of the weeds and vegetables in the fields, reduce the source of insects; timely treat the leaves of the residual plants after harvesting, timely till up, eliminate the insects, and reduce the number of the next generation. Second, the cane and fruit vegetables in the greenhouse can be hung by the yellow plate to trap the adult to reduce the insect base. Hanging one every 3-5 meters, the hanging height is 10-15cm away from the uppermost leaves of vegetables, which can cure mites. The third is chemical control: due to the overlapping of generations of leaf miner, there is no obvious sub-division, and the prevention and control of larvae is the first time for the first time of larval larvae, and the spraying is repeated once every 7-10 days. Prevention 2 to 3 times. The mites on the peas were used for the first time in mid-April, and then again after 7 days. The drug may be selected from 800% to 1000 times solution of 20% chlorfenapyr suspension, or 1000 times of 80% dichlorvos emulsifiable concentrate, or 3,000 times solution of 1.8% avermectin emulsifiable concentrate, or 3,000 times of 2.5% deltamethrin emulsifiable concentrate. Liquid and other drugs, pay attention to the use of drugs. At the same time, prevention and control should pay attention to: when spraying against leaf miner, pay attention to the spraying time. The optimal prevention time is from 9:00 to 11:00 every day. When using, strictly follow the relevant regulations of the safety interval of the drug. It is forbidden to use high-toxic and high-residue pesticides on vegetables. Steam Trap,Flange Drain Primer Valve,Floating Ball Drain Valve,Floating Ball Steam Trap Chongqing Xingjida Import and Export Trade Co., Ltd. , https://www.xjvalvestem.com
Occurrence and control of vegetable leaf miner