The twill moth is mainly harmful to sweet potatoes, vegetables, taro, beans, and in recent years, it has begun to appear in large quantities in tea gardens, which seriously affects the quality and yield of tea. Therefore, farmers must strengthen their measures to prevent the disease. Today, Xiaobian will lead you to understand the characteristic habits, causes of outbreaks and control measures of tea plant twill moth, as follows:
Adults are 16 to 21 mm long, with a wingspan of 37 to 42 mm , yellowish brown to grey-brown forewings , silvery white hindwings , purple reflective , and dark brown veins. The main feature is that there are 3 distinct white tinges from the leading edge of the forewing to the center of the wing (between the ring and the kidney stripe). The eggs are hemispherical in shape, 0.5 mm in diameter, yellowish-white at the beginning of their birth, and purple-black when hatching. The eggs are oval in shape, consisting of 2 to 3 layers of eggs stacked on top of each egg, covered with gray-yellow villi, and each egg generally has tens to hundreds of eggs. The larvae are 35 to 51 mm long, and the body color changes greatly, including black brown, dark green, and gray green, gray green on the tea tree, black brown on the taro, and dark green on the sweet potato. The main features are 5 yellow-white lines (dorsal line, subsorbital line, sub-valve line) on the back and sides of the worm, and a nearly half-moon shaped black spot on each segment of the subsordinal line from the middle chest to the 9th section of the abdomen (the black spots on the tea tree are not obvious), and the valves and pectoral feet are black. The pupal is 15 to 20 mm long, and the pupae are fat red at first, and then gradually become ochre red. The abdomen is densely packed with small circular dots on the dorsal back of the 4th to 7th segment and the anterior margin of the ventral front of the 5th to 7th segment, with a black valve, oval, tilted backwards, and a concave cavity behind the valve. At the end of the abdomen there is a pair of thick curved spines with the base of the spine partially open.
Zhejiang occurs for 4 to 5 generations in a year, and pupae overwinter under the soil, but the possibility of migration is very large. According to the observations in the past 5 years, the first pest of tea plants by twill moths every year is in late June (the second generation), and the outbreak of pest periods is concentrated in the high temperature period from late July to early August, according to the period of harm to tea trees in Shatou Town, it is speculated that the adult blooming period should be in mid-to-late July (the third generation). Adults emerge day and night, hide in weeds or crevices during the day, start to move at sunset, feed on plant nectar for nutritional supplementation, and lay eggs at night. The phototropism is weak, but the tendency to black light is strong, and it likes to be prepared with sweet and sour.
Pre-spawning 1 to 3d, individual feathering that is, tail spawning, feathering 3 to 5d for the peak of spawning, the amount of eggs and nutrition, temperature and other environments are related, generally 3 to 5 pieces, more than 8 to 17 pieces, the general amount of eggs tens to hundreds. According to relevant investigations, the number of eggs in one egg larvae reached more than 300. The eggs are mostly laid on the back of the middle leaves of the tea plant. The egg stage is very much related to temperature. It was recorded that the average daily temperature of 22.4 °C at the egg stage was 7 .3d, 2.9d at 25 °C, 2.4 d at 28.3 °C, and 2 d at 30.7 °C.
The larvae are 6 years old, and the hatching larvae feed intensively, before the 3rd instar, they are harmful to the young leaf flesh of the tea plant, and the 4th instar overeating the young leaves and young stems of the tea tree. The larvae are suspended dead and curl up to the ground in the event of an alarm. After the age of 4, light avoidance appears, hiding in the soil or soil near the tea tree stump during the day, and coming out at night and in the morning to eat. The larval calendar period was inversely correlated with temperature, with the average larval calendar period of 26.7d at 21.2 °C, 16.9d at 26.8 °C, 14.8 d at 29.5 °C, and 12.4 d at 30.2 °C. According to Jiangxi Pengze, the larvae of each age were 1.8 days old, 2.0 days old, 2.4 days old, 2.4 days old, 4 years old 2.5 days, 5 years old 3.0 d, 6 years old 5.0 days, a total of 16.7 days. The larvae mature into the soil 1 to 3 cm to make oval soil chamber pupae. The average daily temperature of the pupal period is 29.2 °C, the average calendar period is 9.4d (3rd generation), the average daily temperature is 23.6 °C, and the average temperature is 12.9 days.
The tea tree twill moth is a temperature-loving pest. In recent years, the summer solstice plum is light, the plum is early, and there is a summer drought from July to August, and the continuous high temperature and little rain are very beneficial to its outbreak. The sweet potato and other gardens in Shatou Town have basically developed into the cultivation of black cow morning tea, and the whole town has a single crop variety and food shortage, which has concentrated on transferring the twill moth to harm the tea tree. Tea farmers blindly increase the amount and frequency of medication, and natural enemies are killed in large quantities, losing the control role of natural enemies. With a large number of chemical fertilizers, the growth of tea plants is too dense, tender green, and the insect resistance is weakened, which is conducive to pests.
First, it is to establish forecasts and forecasts and determine the appropriate period for prevention and control
According to the characteristics of the twill moth as a pest of tea plants in late June and the bloom in early August, it should start in early June, choose the previous year's heavier occurrence, the tea garden area is larger, and the black light lamp or sweet and sour preparation (3 parts of sugar, 3 parts of vinegar, 1 part of wine, 10 parts of water) is used to induce moths, determine the moth blooming period, thereby speculating the incubation period, and determining the appropriate period for 2 to 3 years of age.
Second, it is agricultural prevention and control
Can be combined with shearing, tillage, fertilization and other technologies; The control methods are effective, safe, easy to promote, and the measures are diverse, and the inhibitory effect on the twill moth is long-lasting and comprehensive. Its limitations are slow to see the effect, not easy to perceive, easy to be ignored; The control effect is not obvious, or can only alleviate the pest to some extent, and some measures may sometimes contradict the control of pests.
Third, it is biological control
Biological control refers to the use of organisms and their products to control pests. These include the traditional use of natural enemies and the sterility of insects, the use of insect hormones and pheromones, etc. In addition, there are higher plants that have not yet been utilized. Biological control can overcome the shortcomings of chemical control leading to pest resistance, killing natural enemies and polluting the environment, and is an important part of the pest management of tea plants. According to the survey, there are 800 to 900 species of natural enemy insects in China's tea gardens.
Biological control pathway: Protect and promote the growth of natural populations of natural enemies to increase the natural control of the twill moth. There are various methods of protection, for pruning, the branches and leaves under the platform, can be piled near the tea garden, in order to facilitate the natural enemies to move back to the tea garden, artificially removed egg blocks, insect buds, protective sacs, etc. should be placed in the altar surrounded by water, bowl, to be twill nocturnal moth feathering out after the treatment. Collect spiders with grass handles and release them in tea gardens to control twill moths; Use artificial nest boxes to attract beneficial birds to peck at tea garden twill moth larvae, etc. Mass reproduction releases predators. When the natural control of local predators is insufficient, especially in the early stages of twill moth disasters, good control effects can be achieved by artificial mass breeding and release of natural enemies.