(1) ① Morphological characteristics of adults. Both male and female moths are grayish brown, and the female moth is larger than the male moth, with a body length of 12 ~ 17 mm, degenerated wings and silky and brown antennae. The length of male moth is 10 ~ 15 mm, and its wings spread 26 ~ 35 mm.
Two eggs. Oval, pale green at birth, then gradually turned brown and shiny, and turned dark purple near hatching.
③ Larvae. Larvae * * * is 5 years old, which is purple-black at first, and then gradually turns to light brown and bluish gray. The mature larva is about 40 mm long. 1 instar larvae have 1 white stripes on the chest and ventral back from the first to the fifth section, 7 white longitudinal stripes on the body surface of the 2nd instar larvae and 13 white longitudinal stripes on the 3rd instar larvae. The longitudinal stripes turn yellow or grayish white at the 4th instar, and there are 25 intermittent grayish white longitudinal stripes at the 5th instar.
④ Pupa. Spindle-shaped, bordeaux to dark brown, long 13 ~ 15 mm, the female pupa is slightly larger (Figure 17).
Figure 17 date geometrid
(2) A brief history of life history: the jujube geometrid occurs in most jujube areas 1 year 1 generation, and in some jujube areas 1 year, it has two generations. The pupae overwinter in the soil with a depth of 10 ~ 20 cm under the crown, and the pupae are concentrated in the range of 1 m near the base of the trunk. Emergence began in the middle and late March, and the peak of emergence was in the middle and early April, and the emergence period was more than 50 days. The male moth emerged in the afternoon and flew behind the trunk or behind the big branches to lurk; After eclosion, the female moths first lurk in the dark places such as the soil surface and under weeds, climb to the tree at sunset to find the male moths to mate, start laying eggs the next day, and reach the peak of laying eggs 2 ~ 3 days later. Eggs are laid in cracks in the rough epidermis of trunks and branches. Eggs need to hatch 10 ~ 25 days, most of which are more than 20 days. Egg hatching is related to temperature and humidity. When the weather is dry and the temperature is low, the incubation period of eggs is longer, usually starting in the middle and late April. Newly hatched larvae gather at jujube stocks to eat new buds, and then they will spread out to do harm. Larvae has suspended animation, which is also called "cannibalism" because it will rotate after being frightened in crawling. 1 ~ 2 instar larvae leave silk where they climb, so it is difficult to grow around the buds. After the 3rd instar, the larval food intake increased greatly, which caused serious harm to young leaves. At the age of 4 ~ 5, they eat not only young leaves, but also buds and young fruits. The amount of mature food of larvae gradually decreases, which is more than that in the shade, during which it can be captured artificially. From late May to late June, the mature larvae are buried and pupated.
(3) Prevention and control methods ① Protect and utilize natural enemies. The natural enemies in larval stage are sparrows, magpies and other birds; Parasitic insects include jujube geometrid, silkworm and jujube geometrid. Trichogramma can be released artificially in jujube orchards with conditions, and the parasitic rate can reach 96. 1%, which can basically control its harm.
② Agronomic measures. Before the emergence of adults in early spring, we should dig out the soil in the trunk 10 ~ 20cm, screen the pupae, then concentrate the pupae in the basin, cover it with wet soil, and cover the basin with gauze. After being stung by natural enemies, jujube orchards should be released, and the remaining pupae or emerging adults should be fed to chickens or burned. Using the characteristics of adults climbing to trees to lay eggs, before the emergence of adults, tape is wrapped around the smooth trunk to prevent adults from laying eggs. If you can't buy adhesive, you can tie a plastic film skirt with a downward horn at the smooth part of the trunk to prevent the female moth from climbing the tree to catch the female moth in the morning. Or, you can tie a straw rope in the middle of the trunk and use the sex information of the female moth to lure the male moth to mate and lay eggs. After the spawning period, you can untie the straw rope and burn it centrally. It should be noted that the grass-wrapped circle can't let the female moths cross trees to mate and lay eggs, otherwise it will be invalid. In the larval stage, the dead larvae are used to vibrate branches with wooden pestles, and at the same time, chickens are released to eat insects or gathered to feed them, thus destroying the larvae.
③ Drug control. Before the larva 1 ~ 2 instar, the whole tree was sprayed with 500 ~ 1000 times Bt emulsion (1000 billion live spores/g) or 1500 ~ 2000 times 25% diflubenzuron No.3. It can also be used at the peak of larval occurrence and mixed with pyrethroids for better control effect. It can also be controlled with 30% acephate 800 ~ 1000 times, 50% phoxim 1000 ~ 1500 times and 50% malathion 1000 ~ 1500 times.
At the same time, jujube inchworm is also harmful to jujube trees, such as jujube inchworm and locust inchworm. The female moth of the jujube inchworm has wings. In agricultural control measures, it should be emphasized that pupae should be dug to destroy wintering sites, and other control methods should refer to jujube inchworm.