Common pests of Ligustrum lucidum and their control

Ligustrum lucidum is a semi-evergreen shrub of the genus Ligustrum lucidum of Oleaceae. Because of its golden shoot, pruning resistance and drought resistance, it is often used to decorate flower beds and green belts with safflower wood, rhododendron, cypress and so on. Often due to the use of high-density planting, insect pests occur more seriously, resulting in slow growth or no new branches, weak growth or even death. The common and seriously harmful pests of Ligustrum lucidum are: pink scale, Ligustrum lucidum, Ostrinia furnacalis.

1. Dendrolimus koningii

Adults and nymphs lie on the branches and leaves of Ligustrum lucidum and suck plant sap with piercing mouthparts, resulting in water loss and wilting of branches and leaves, and even death, and can also induce coal pollution disease.

1.1 morphological characteristics

The adult body is flat and oval, pink, and the body surface is covered with white wax powder; the nymph is oval, flat and yellowish, and the body surface is also covered with white wax powder; the egg is oval, light yellow, and the oocysts are white cotton floc.

1.2 Life history and habits

Kangs pink scale occurs three generations a year in Hudingshan area, and the eggs survive the winter in the host's branch crevice, saw mouth, warping skin or hidden places of weeds, soil clods and fallen leaves around the rhizosphere. The hatching began in early May of the following year, and the peak incubation periods of the three generations were mid-late May, mid-late July and late August, respectively, and there was a small peak in September, after which the female adults spawned and overwintered.

1.3 Prevention and control measures

1.3.1 change the environment, enhance the tree potential, change or create environmental conditions that are not conducive to the occurrence of pink scale, reduce or weaken the harm of pink scale. Ligustrum lucidum with dense plants is easy to be harmed by pink scale, so we should reasonably determine the planting density, make good ventilation and drainage, strengthen fertilizer and water management, and enhance the natural insect resistance of trees and plants.

1.3.2 reducing insect sources combined with pruning, cutting and burning serious insect branches, in order to reduce insect sources and reduce damage.

1.3.3 during the peak incubation period of the first generation pink scale, spraying appropriate amount of insecticide can greatly reduce the pest for one year. The commonly used chemical agents are: 1000 times of omethoate and 1000 times of scale mites. When the harm is serious, the effect is excellent by evenly spraying Lesbon plus penetrating agent.

1.3.4 the natural enemies of the natural enemy, Chrysopa and many kinds of ladybugs, should be protected and utilized.

2 Ligustrum lucidum submerged leaf jumper

It mainly harms the leaves of Ligustrum lucidum, the adults feed on the leaves, resulting in round or irregular spots on the leaves, the larvae sneak into the skin, drill the curved insect path under the epidermis, destroy the chloroplast structure and weaken the photosynthesis. make a large number of leaves scorched and affect the landscape effect of green space.

2.1 morphological characteristics

The adults of Ligustrum lucidum are oval or round, black, with metallic luster on the back, and an oval red plaque in the center of the wing sheath; the larvae are yellowish, thick and short, with tumor-like protuberances on both sides of the abdominal 1-8 segments.

2.2 Life and habits

In Pingdingshan area, the mature larvae overwintered in the soil layer, and the adults emerged in late April of the following year, the first generation from May to mid-June, the first generation from late June to late June, and the third generation from late August to September.

2.3 Prevention and control measures

2.3.1 physical control removes lichens and moss from tree trunks in early winter, blocks tree trunk crevices, reduces overwintering places, removes insect leaves during spring shoot growth, removes new fallen leaves, centrally burns, and destroys larvae before pupation.

2.3.2 Chemical control can be sprayed with 1000 times of Lesbon and penetrating agent during the hazard period, or 2000 times of avermectin or 8000 times of omethoate.

3. Ostrinia furnacalis

The larvae fall from leaves to feed on the host mesophyll, leaving epidermis, which has the characteristics of concentrated occurrence, large number of insect population and overeating. The serious damage period of the insect larva was from May to June. The seriously damaged golden leaf privet hedge plant was scorched yellow, the branches were dry and the leaves were black, which seriously affected the growth and greening effect.

3.1 morphological characteristics

The adult head is white, the forehead is covered with yellow scales, the antennae are yellow-white at the base of the antennae, the rest are white, the lips are white at the first section, the rest are brown, the neck is brown, the body and wings are milky white, with silk luster, and there is a yellow band on the front edge of the wings. there are three yellowish spots from the base of the wing to the end of the middle chamber. The old mature larva has a yellowish green body, a yellowish brown head, brown mouthparts, and a small black spot on both sides of the back plate of the chest and above the 8th abdominal throttle. The spot is prismatic or tadpole-shaped. The pupa is green in the early stage, green-brown after half a day, yellowish brown in near Eclosion, dark-brown compound eyes, and clear markings on the wings. There are no 8 gluteal spines in the abdomen, and the buttocks are slightly curled and arranged in an arc. The egg is flat and oval, yellowish green at first birth and dark brown when it is nearly hatched.

3.2 Life habits

The insect occurs for three generations a year in Hengyang, Hunan Province, and overwinters as pupae in the soil near its host. The overwintering pupae began to Eclosion and lay eggs in late April, the first generation larvae began to hatch at the end of April, the second generation larvae began to hatch at the beginning of June, and the third generation (overwintering generation) larvae appeared in early July and began to pupate in the middle of July.

3.3 Prevention and control methods

In late May, during the occurrence of overwintering adults, leaves and branches were sprayed with 50% phoxim EC 1000: 1200 times; in early May, 40% omethoate EC 1000 times was used to control larvae, and the control effect was more than 98%; in late May, leaves and branches were sprayed with 2.5% deltamethrin EC 2500 × 3000 times to control the first generation adults. The insect damage can be controlled by spraying leaves with 40% omethoate EC 1000-1200 times in early June.

3.3.2 pruning the tender shoots of Ligustrum lucidum in time from late April to early May and from late May to early June can prevent adults from laying eggs on the ununfolded leaves at the top of the shoots, kill newly hatched larvae and prevent the occurrence of the pest.