Cotton bollworm and smoke green worm are two very similar insects, which are difficult to distinguish in production, and belong to the lepidoptera noctuidae family, also known as the cotton bollworm and the smoke moth, which are widely distributed. Cotton bollworms are a variety of crops such as cherry tomatoes, okra, lettuce, crumpled cabbage, brussels sprouts, melons, lentils, hollandaise beans, sweet peas, sweet corn, vegetable soybeans, apples, pears, oranges, peaches, plums, grapes, figs, strawberries, cotton and so on. Tobacco insects are harmful to tobacco, peppers, tomatoes, pumpkins, cotton, corn, sorghum, hemp, soybeans, peas, lentils and so on.
<b>The characteristics of the pest</b> are that the larvae feed on the buds, flower utensils, fruits and seed pods of the plant, and also drill the stems, ears, and vegetable bulbs of the plant, and eat young stems, young leaves and young shoots in the early stage.
<b>Morphological characteristics</b> Of cotton bollworm Adult worms are 14 to 18 mm long, have a wingspan of 30 to 38 mm, and are gray-brown to yellow-brown. The forewings have brown rings and kidney-shaped stripes. There are two brown streaks on the anterior margin of the kidney-shaped stripes, and the outer side of the nephroform stripes is a brown broad transverse band, with black spots between the veins in the end area. The hindwings are yellowish white to greyish brown and the end area is brown to black. The male moth has 1 inverted hook at the end of the yang, and the small conical horn-like organs in the male stem are large and few (about 12 pairs). The female moth mating sac has small triangular spines on the cysts, in addition to wrinkles. The egg is about 0.5 mm long, hemispherical, milky white, with a reticulated pattern, there are 1 to 2 short longitudinal edges sandwiched between the two longitudinal edges, mostly bifurcated or triple bifurcated, the central longitudinal edges are 25 to 30, mostly 26 to 28, and the egg holes are not obvious. The body length of the mature larvae is 30 to 42 mm, and the body color varies greatly. From light green and light red to reddish brown and black purple, it is commonly green and reddish brown. The head is yellowish brown , with a dark longitudinal line of dorsal, sub-dorsal and valve lines , white valves , and a double-sequence mid-band with a ventral toe hook. The two anterior thoracic lateral hairs (L1, L2) are tangent or intersect with the lower end of the anterior thoracic valve. The surface of the body is covered with small thorns, and its underlying acne is larger. Pupae are 17 to 21 mm long and yellowish brown. There are 7 to 8 rows of semicircular incirclements on the back and ventral surface of the fifth to seventh segments of the abdomen, and 2 gluteal spines.
Figure 1 Cotton bollworm is a pest tomato Figure 2 Cotton bollworm larvae Figure 3 Cotton bollworm adult
Fig. 4 Inverted small hook at the end of the male male adult stem of cotton bollworm Fig. 5 Wrinkles and small triangular spines on the mating sac attachment of female bollworm Fig. 6 Cotton boll eggs enlarged
and small conical horns inside the yang stem
Smoke green worm is very similar to cotton bollworm. The main differences are: the adult body color is yellower, the lines on the forewing are clear, and the hindwings have a brownish black line on the inside of the middle of the broadband, and the outer side is slightly concave. There are no small hooks at the end of the male moth's male stem, and the long-conical horn-like organs of the male stem are small and numerous (about 23 groups). Female moths have only wrinkles on the sac attachment of the mating sac and no small triangular spines. The eggs are slightly flattened, pale yellow, longitudinal biordal, mainly 1 long and 1 short, the central longitudinal edges are 21 to 26, mostly 22 to 24, and the ovary is obvious. The larvae have two lateral hairs (L1, L2) wired away from the lower end of the anterior thoracic valve, and the small spines on the surface of the body are shorter. The anterior segment of the pupal is slightly stubby. Valves are small and low, with few protrusions.
Figure 7 Tobacco green worm is a pest bell pepper Figure 8 Smoke green worm larvae Figure 9 Smoke green worm adult
Fig. 10 Cone-shaped horn-shaped apparatus in the male adult stem of the smoking acoccite Figure 11 Wrinkles on the mating sac attachment of the female adult of the cyst of the gyneus Fig. 12 Enlarged eggs of the gyrus aphidge
<b>Lifestyle habits </b>
Cotton bollworm occurs in 2 generations in the northeast, 3 generations in Inner Mongolia and Xinjiang, 4 generations in north China, 5 to 6 generations south of the Yangtze River, and 7 generations in Yunnan. Pupae overwinter in the soil. Adults have light-oriented and poplar branch habits. Mating and spawning at night. The eggs are scattered at the apex of the plant and on the young shoots, young leaves, calyxes, pods, panicles and stem bases. Each female lays 100 to 200 eggs. The egg development calendar period is 6 to 14 days at 15 °C, 4 days at 20 °C, 4 days at 25 °C, and 2 days at 30 °C. The hatching larvae can only nibble on young leaves, flower buds, young shoots, etc., and generally begin to drill moths in the three moles, and the four to five moths shift to eat frequent (sweet) peppers, and are relatively weakened at six years. A single larvae can burrow multiple fruit spikes, fruit pods, etc. The larvae are 6 years old and have a developmental period of 28 days at 20 °C, 18 days at 25 °C, 13.5 days at 28.5 °C, and 17.5 days at 30 °C. The old mature larvae pupate in the soil chamber in the 3-9 cm topsoil layer, and the pre-pupal stage is about 3 days. Pupal development calendar period is 28 days at 20 °C, 18 days at 25 °C, 13.5 days at 28.5 °C, and 9.5 days at 30 °C. Cotton bollworms like warmth and humidity. Adults lay eggs at temperatures above 23 °C, and rarely lay eggs below 20 °C. Larval development is most suitable at 25 to 28 °C and relative humidity of 75% to 90%. The monthly rainfall is more than 100mm and the relative humidity is more than 70%. Excessive rainfall causes soil compaction, which is not conducive to the larvae entering the soil to pupate, and the mortality rate of pupae increases. In addition, heavy rains can wash away cotton bollworm eggs. Adults feed on nectar-derived plants to supplement nutrition. The first generation of adult insects occurs in the flowering stage of other crops, if the temperature is suitable, the occurrence is large, and the second generation of cotton bollworm is seriously harmful. The main natural enemies are broad-eyed bee, corn borer red-eyed bee, tooth-lip wasp, cotton bollworm side groove cocoon bee, broad-legged wasp, umbrella skirt chase fly and grass small black spider, T striped tarantula and so on.
Smoking green worms The occurrence of green worms is less algebraic than that of cotton bollworms, and occurs slightly later than cotton bollworms. Adults also lay fewer eggs than cotton bollworms. The living habits of the larvae are similar to those of cotton bollworms, but there are great differences in feeding properties and pest characteristics. Smoke green insects are mainly harmful spicy (sweet) peppers. In the early stages of growth, spicy (sweet) peppers mostly lay eggs on the front or back of the upper leaves, and in the later stages, they mostly lay eggs on fruit surfaces, sepals or petals. Usually only 1 capsule is produced per place. After three times, the fruit began to be mothed, as long as the food is sufficient, it generally does not produce fruit (different from cotton bollworm). In the field there is 1 more fruit and 1 worm. However, when there is little food and the amount of pests is large, there can be 2 to 3 larvae in a fruit, each living in 1 room. It can also be turned into a pest when the larvae like to eat the placenta and flesh of the fruit, or when the damaged fruit is rotten and the larvae are not yet ripe. Usually the larvae are drilled out of the fruit after they are ripe and pupated into the soil. Therefore, field control is more difficult than cotton bollworm, and the administration must be mastered before the larvae drill the borer fruit. Colored bell peppers are mostly affected in summer and autumn. In areas with large tobacco cultivation areas, the occurrence of tobacco green insects in vegetable fields such as spicy (sweet) peppers is mostly harmful. Adults can lay eggs on tomatoes, but very few larvae survive. The developmental period is 3 to 4 days for eggs, 11 to 25 days for larvae, 10 to 17 days for pupae, and 5 to 7 days for adults. The main natural enemies are basically the same as cotton bollworms.
<b>Control methods </b>Cotton bollworm and smoke cymbal control methods are similar, the tobacco cymbal larvae are no longer drilled out after the three moths, and the medicinal control must be carried out before the moth.
1. Ploughing the ground in winter and early spring to eliminate pupae and reduce the source of overwintering insects in the field.
2. Use black light lamps, high-pressure mercury lamps, poplar branch handles or sexual attractants to trap pots to trap adult insects.
3. According to the selectivity of cotton bollworms to different hosts, consciously plant the food-loving host crop lure belt in the field, induce cotton bollworms to lay eggs, and reduce the harm to the production of vegetables.
4. Combined with field management, the leaves, fruits and young shoots of insect eggs are removed with the whole branch, and the cultivation and irrigation are increased at the pupal stage, and the normal pupae of cotton bollworms is destroyed.
5. Continuous spraying of Bacillus thuringiensis Bt emulsion or HD-1 powder or bollworm karyotype polyhedrovirus after 3 to 4 days and 6 to 8 days after the peak of eggs. Before the larval 2nd instar (unpolluted moth), 5% Nongmente emulsion 3000~4000 times liquid, 10% Torrebo suspension 1500~2000 times liquid, 3% Möbilang emulsion 1000~2000 times liquid, 5% jammedk emulsion 1000~2000 times liquid, 52.25% nongdile emulsion 2500~3000 times liquid, 5.7% Baishude emulsion 3000~4000 times liquid, 12.5% Baofu suspension 8000~10000 times liquid spray. After drilling moths, it is advisable to spray in the morning or evening when the larvae are drilling out.
bibliography:
1. China Agricultural Press, Zheng Jianqiu, "Modern Vegetable Disease and Pest Identification and Control Manual";
2. China Agricultural Press, edited by Gao Wenqi and Yu Fanmin, "Handbook for Identification and Control of Vegetable Pests and Insect Pests";
3. China Agricultural Press, edited by Zhao Kuihua, "Grape Diseases and Pests Primary Color Atlas";
4. Huaxia Publishing House, written by Lü Peike, Pang Zhen, etc., "Primary Color Atlas of Chinese Fruit Tree Diseases and Insects";
5. Shanghai Science Popularization Publishing House, edited by Zhao Meijun and Li Lizhen, "Colorful Insect World";
6. Agricultural Press, Chief Editor of Beijing Agricultural University, General Theory of Entomology.