How to control scale insects in privet hedge

In recent years, with the application of Ligustrum lucidum and Ligustrum lucidum in urban greening, diseases and insect pests on privet have become a major problem in garden maintenance and management. The scale insects on the greening plants of Ligustrum lucidum are mainly white wax scale. It is reported that Kang's pink scale occurred on the privet hedge in Hebei province. The identification characteristics and control measures of white wax scale are introduced as follows:

Distribution and harm

White wax scale Ericeruspela (Chavannes) belongs to Homoptera, Coccidae. It is widely distributed in China. To harm longleaf privet, privet, Japanese privet, lobular wax, white wax, water wax, cedar, citrus, camellia and grapefruit and so on.

Kang's pink scale (PseudococcuscomstockiKuwana), also known as mulberry pink scale, pear pink scale, plum powder scale belongs to the family Coccidae. It mainly harms kumquat, Robinia pseudoacacia, camphor tree, bergamot, apple, pear, peach, plum, apricot, Hawthorn, grape magnolia, unicorn palm, bamboo evergreen, ivy, jasmine, sugar maple and so on.

Harm symptoms: the two kinds of pests are harmful to adults and nymphs on the host branches, resulting in tree weakness, slow growth, and even branch death.

Morphological characteristics

The recognition characteristics of the white wax scale are as follows: the back of the female adult is raised, clam shell-shaped before fertilization, and expands into a hemispherical shape after fertilization, about 10 mm long and 7 mm high. Yellowish brown, light red to reddish brown, scattered light black spots, yellowish green abdomen. The male adult is about 2 mm long, yellowish brown, transparent wings, iridescent luster, and 2 white wax filaments on the tail. Eggs: the female eggs are reddish brown and the male eggs are light yellow. The nymph is yellowish brown and ovoid.

The recognition characteristics of Kang's pink scale: adults. The female adult is oval, flattened, 3~5mm long, pink, covered with white wax powder, with 17 pairs of white wax thorns on the margin, and one pair at the end of the abdomen almost equal to the length of the body. The antennae are mostly 8 nodes. Gastroschisis 1, large, oval. The anal ring has 6 anal ring thorns. The gluteal flap is well developed, with a gluteal flap thorn and several long hairs at the top. The porous glands are distributed on both sides of the back and abdomen of the worm. There are 17 pairs of piercing holes with a large number of body hairs, which are distributed on both sides of the dorsal and ventral sides of the insect body, and the body hair is slightly longer along the dorsal midline and near it. The male adult has a purple-brown body, a body length of about 1mm, a wingspan of about 2mm, a pair of wings, transparent. The egg is oval, light orange-yellow, and the oocyst is white and flocculent. Nymphs are oval, flat and yellowish. The pupa is lavender with long 1.2mm.

Life habits

Wax scale produces one generation a year and overwinters as fertilized female adults on branches. In the following year, the pregnant eggs of the female adults expanded in March and began to lay eggs in early April, and the egg period was about 7 days. The nymph stage of white wax scale coincided with the florescence of lobular privet in Shanghai area. The newly hatched nymphs parasitized on the leaves near the mother, and transferred to the branches after the 2nd instar. The male nymphs were fixed and secreted a large amount of white wax, covering the insect body and branches. In severe cases, the whole branch was white rod-shaped. The male adults emerged in early October and died after mating. The fertilized female adults gradually grew up and overwintered one after another as the temperature dropped. The newspaper reported that the nymph hatched in late June in Dalian, but there was no overwintering in Kunming, and the nymph began to hatch in mid-March. Continuous high temperature, drought or continuous rain can cause a large number of nymphs to die.

The pink scale usually produces three generations a year and overwinters with oocysts in the gaps of tree trunks and branches. The peak hatching period of each generation of nymphs is mid-late May, mid-July and late August. The developmental period of nymphs is 35-50 days for females and 25-37 days for males. The male nymph pupates in a long white cocoon. Each female adult can lay 200 to 400 eggs, and the oocysts are mostly distributed in the cracks in the bark. On flowers and trees, adults and nymphs mostly gather on buds and twigs to do harm.

Control measures: there are few diseases and insect pests in the first year after planting privet hedge, and scale insects are easy to occur because of poor ventilation and light transmission after the hedge is formed in the second year.

1. Strengthen quarantine: strictly implement the quarantine system and do not introduce insect-carrying seedlings. Do not take scions or cuttings from worm-carrying seedlings.

two。 Scientific management: winter combined with pruning to eliminate adults to avoid the occurrence of a large number of nymphs in the coming spring. Strengthen management, pay attention to ventilation, rational fertilization, scientific watering, enhance tree potential and disease resistance. During the growing period, try not to do strong pruning. When pruning is necessary, spray protective fungicides such as Huapingdan 300x liquid or 1500 times mancozeb or 1000 times carbendazim every 7 to 10 days after pruning, 3 to 4 times continuously.

3. Timely observation: often check the insect situation, check whether there are white flocs, early detection, timely prevention and control.

4. Protect natural enemies: pay attention to protect and utilize the natural enemies of shell insects, such as parasitoids, ladybugs, lacewings and so on.

5. Chemical control: in the peak egg hatching period or the first instar nymph stage, the effect of drug control is good. Using 1000 / 1500x liquid of killing scale or 1000 times liquid of scale killing or rapid culling of 1000m / 1500x solution is sprayed once every 5 to 7 days, and the drug is used continuously for 2 to 3 times. All of them can be eradicated.

When controlling adult scale, 800 / 1000 times liquid of killing scale can be sprayed evenly.

When spraying, pay attention to spraying the whole plant (including diseased plants and healthy plants), and evenly apply medicine on both sides of the leaves; when the number of damaged plants is small, wet cotton balls soaked in oil or alcohol can be used to wipe the harmful places repeatedly, which can kill the nymphs completely, and the effect is very good.