The living habits and prevention methods of star beetles (the most common pest)

In our country, the star beetle is the most common. Star beetles are also known as citrus star beetles and silver star beetles. The domestic distribution starts from Jilin and Liaoning in the north, to Gansu, Shaanxi, Sichuan, and Yunnan in the west, to Guangdong in the south, and to the coastal provinces and Taiwan in the east. Distributed abroad in Japan, Myanmar, North Korea, etc. It damages poplar, willow, elm, locust, walnut, mulberry, red toon, catalpa, casuarina, tallow tree, sycamore, acacia, neem, sycamore, citrus and other fruit trees.

This insect is about 4 cm long, strong and black, with white spots on its wing elytra, which is very eye-catching. The difference between this species and A. glabripennis is that there are small black particles at the base of the elytra, while the base of the latter's elytra is smooth. The antennae are filamentous, black and white, about 10 cm long.

The eggs are oblong, about 5-6 mm long and 2.2-2.4 mm wide. It is white at first birth and gradually turns to light yellowish white later on.

Larvae Mature larvae are 38-60 mm long and milky white to light yellow. The head is brown, rectangular, the middle part is wider in front and overflows in the rear; the frontal slit is not obvious, the upper jaw is narrow and long, and there is one pair of single eyes, brown; the antennae are small, with 3 segments, the 2nd segment is wide horizontally, and the 3rd segment is nearly square. The front chest is slightly flat, the ossification area of the back plate is in a "convex" shape, and there are two flying crow-shaped patterns above the convex pattern. 9 pairs of stomata, dark brown.

The pupa is spindle-shaped, 30 to 38 mm long. The pupa is light yellow when it first emerges. Before eclosion, all parts gradually turn from yellowish brown to black. Wing buds extend beyond the posterior edge of the third segment of the abdomen.

Biological characteristics: In southern Zhejiang, one generation occurs per year. In some areas, there are two generations every three years or one generation every two years. The larvae overwinter in the xylem of the damaged host. The overwintering larvae begin to move after March of the following year. In Zhejiang, around the Qingming Festival, most larvae have pupae that are 3.5-4 cm long and 1.8-2.3 cm wide and have circular eclosion holes that go straight to the epidermis. Feed and lie in the pupa chamber. Pupation begins when the temperature stabilizes above 15°C in early April, and pupation is basically completed in late May. The length of the pupa stage varies from place to place, ranging from 0 to 15 days in Taiwan; about 20 days in Fujian; and 19 to 33 days in Zhejiang. Adults begin to emerge in early May, and the peak of adult emergence is at the end of May and early June. After emergence, the adults stay in the pupa chamber for 4-8 days. After their bodies harden, they emerge from the round emergence holes and eat the young branches of the host. The bark of the tree is used to supplement nutrients, and mating takes place after 10 to 15 days. In Zhejiang, mating can occur all day long, but it is most common from 8 a.m. to 5 p.m. when it is clear and windless. In Fujian, adult insects are mostly active, mating, and mating before dusk. When laying eggs, they are also more active at dawn, mostly resting on the branches at noon, and mostly resting after 9 pm and on cloudy and rainy days. Male and female insects can mate many times. 3-4 days after mating, in early June, the female adults lay eggs at the lower part of the trunk or the lower part of the main side branches. The peak of egg laying is in early July, with most eggs within 10 cm from the base of the trunk. 76%; 18% within 10 cm to 1 meter, and it is related to the thickness of the trunk diameter at breast height, with the diameter at breast height of 6-15 cm being the most common, and 7-9 cm accounting for 50%. Before laying eggs, first bite a "T" or "human" shaped groove about 2 mm deep and 8 mm long on the bark, and then insert the ovipositing tube into the bark gap on one side of the groove to lay eggs. Generally, one egg is laid in the trough every moment, and a gelatinous substance is secreted to seal the eggs after laying. Each female can lay 23-32 eggs in her lifetime, up to 7l eggs. The lifespan of adults is generally 40-50 days, and adults are active from late May to late July. The flight distance can reach 40-50 meters.

The egg period lasts from 9 to 15 days and hatches in mid-June. Mid-to-late July is the peak of hatching. After the larvae hatch, they burrow in from the place where the eggs are laid, and feed downward between the epidermis and xylem, forming irregular flat worm canals filled with worm feces. After one month, the cavities begin to eat into the xylem. When the cavities reach a depth of 2-3 cm in the xylem, they turn to the upper cavities. The heights of the upper cavities vary, the cavity widens, and vent holes are opened through which feces is discharged. After late September, most of the larvae turn their heads downward and move downward along the protozoal path. After entering the hole, they open a new path to bore into the lower part, where they cause damage and overwinter. The entire larval period is as long as At 10 months old, the insect canal is 35-57 cm long.

There are not many natural enemies of the star beetle. An egg parasitoid was found in Zhejiang; ants eat the larvae, and earwigs eat the larvae and pupae. In addition, a parasitic fungus was found on the larvae.

In addition, the larvae of the star beetle are also used in traditional Chinese medicine, which can treat diseases such as fever, sore throat, convulsions, malnutrition and heart disease.

Prevention and treatment methods

(1). May-June is the peak period for adult insects, and adults can be hunted and killed.

(2). Use 1 part of quicklime and 4 parts of water. After stirring evenly, paint 0.5 meters high around the base of the trunk to prevent the spawning of star beetles.

(3). After discovering the groove where the star beetle lays eggs at the base of the trunk, you can use a small hammer to hit the groove to kill the larvae and larvae inside.

(4). Spray 20% dichlorvos kerosene liquid on the groove with yellow foamy glue to kill eggs.

(5). After judging the location of the infestation based on the color, thickness, and moisture of the wood chips discharged from the chip discharge hole, insert a steel wire to kill or hook out the larvae.

(6). Use cotton wool dipped in 80% dichlorvos stock solution or 50 times of 25% DDT emulsifiable concentrate, stuff it into the larvae tunnel, and kill it. Larvae in the tunnel.

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