Identification and Control Methods of the Oriental Beetle

The Oriental beetle, also known as the black velvet chafer and the velvet chafer, belongs to the order Coleoptera, family Scarabaeidae. It is widely distributed with a diverse diet, and both adults and larvae can cause damage, harming more than 100 species of plants. Adults feed voraciously on several dozen species of garden plants, including poplar, willow, cherry blossom, white magnolia (Magnolia denudata), purple magnolia (Magnolia liliiflora), goldenrain tree, Chinese parasol tree, ornamental peach, crape myrtle, and photinia.

Morphological characteristics: adults are 7 to 9 mm long and 4.5 to 6 mm wide, oval-shaped, narrow at the front and broad at the rear; newly emerged adults are brown, gradually turning dark brown or black, with the body surface densely covered in short brownish-black hairs that have a velvety sheen; antennae have 10 segments and are reddish-brown; the pronotum is densely covered with fine punctures; each elytron bears 9 shallow longitudinal grooves, with fine and dense punctures. Eggs are oval, 1.2 mm long, milky white, and smooth. Larvae are milky white; mature larvae are about 15 mm long with a head width of about 7 mm (Z7 mm in the source), with 1 anterior epicranial seta and 1 frontal seta on each side of the head; above the base of each antenna there is 1 brownish ocellus-like spot formed by pigment, without a lens; the spine row on the ventral surface of the anal segment consists of 20 to 23 conical spines forming an arc-shaped transverse band that is interrupted at the center. Pupae are yellowish-brown, about 8 mm long, with vermilion compound eyes.

Life habits: 1 generation occurs per year. Adults overwinter in the soil. In the middle and lower reaches of the Yellow River, adults generally begin to emerge and become active in late March to early April of the following year, when the soil temperature at 10 cm reaches above 10°C; mid-April to May is the peak emergence period for adults; the suitable temperature for activity is 20 to 25°C. Adults hide by day and emerge at night, are strong fliers, and at dusk often fly around tree crowns, favoring feeding on the leaves, tender buds, flower buds, or petals of relatively tender garden trees (shrubs and small trees); the damage is severe. The damage is characterized by clustered, continuous feeding, gluttonous eating, and a large food intake. Sometimes all the leaves of an affected tree are eaten bare, while adjacent plants show no signs of damage. Adults are strongly phototactic, exhibit death-feigning behavior, and have the habit of emerging en masse after rain. The number of adults decreases in June. Early to mid-May is the peak mating period for adults; male adults die after mating. Female adults lay eggs in soil at a depth of 10 to 15 cm. Eggs are laid singly or in clusters of more than 10 together. Generally, each female lays several dozen eggs, and the egg stage lasts 5 to 10 days. Larvae have 3 instars and feed on tender roots and humus. Mature larvae pupate in soil at a depth of 20 to 30 cm, with the peak emergence period in mid to late August. Most adults that emerge in the same year do not come out of the soil and overwinter in dormancy.

Control methods

1. Taking advantage of the adults' death-feigning behavior and clustered damage, choose warm, windless evenings from 6 to 8 p.m., spread plastic film under trees with obvious adult damage, and use manual shaking to dislodge and kill them; the effect is good.

2. For flowers and trees with obvious continuous damage, during the peak period of adult activity at dusk, spray around the tree crowns with 40% omethoate emulsifiable concentrate at 1000 times dilution or 90% trichlorfon at 800 times dilution and other strongly odorous solutions; this can kill most adults, and those not killed generally migrate elsewhere.

3. Based on the adults' strong phototaxis, where conditions permit, 1 black light trap can be installed every 3 to 5 mu for trapping and killing.

4. When applying organic fertilizer to lawns and garden trees, it must be fully decomposed and disinfected before use; the Oriental beetle favors chicken manure, so special attention is needed when using it. This beetle mainly lives in shallow soil; doing a good winter irrigation in early winter and thoroughly watering the green-up water in spring can eliminate most overwintering adults.

5. During the peak damage period of adults and larvae, before rain or watering, scatter 3 kg of 3% carbofuran granules per mu, or mix 500 mL of 40% isofenphos-methyl emulsifiable concentrate per mu with poisoned soil and spread evenly.