Integrated control methods of licorice insect pests

Hock coarse horn firefly beetle

This insect is a leaf-eating pest of the subfamily Chrysomelinae, which is very harmful to licorice and is one of the main obstacles to the development of licorice production. The insect is distributed in different degrees in Hexi region of Gansu Province and Glycyrrhiza uralensis producing areas in Liaoning Province. It mainly harms Sweet Glycyrrhiza uralensis but not other Arbor, shrub and grass plants. In the whole growing season, the damage of adults is mainly caused by adults, and the food intake is large, and the damage of adults and larvae often overlap.

Control methods: some experiments showed that dichlorvos emulsion, trichlorfon, phoxim emulsion and omethoate emulsion all had good insecticidal effect, and the insecticidal effect of 1000 times mixture of dichlorvos and trichlorfon was the best before 11:00 in the morning. In addition, the 1000-fold spray of dichlorvos emulsion also has excellent control effect.

Leaf beetle

Yulan leaf beetle and macular leaf beetle are the main leaf-eating pests of Glycyrrhiza uralensis in Hetao beach and lake silting land, and they are also distributed in other producing areas, but the harm is light or not harmful. All the adult larvae feed on licorice leaves, and the leaves are riddled with holes. Feed on mesophyll and leaf back, often residual veins and upper epidermis, uneven periphery of wormholes, wavy. In serious cases, there are no intact leaves in the licorice field, and the residual leaves of the injured licorice are yellow and shedding, which seriously affects photosynthesis and poor plant growth. The main damage period is from mid-July to late August, with 2-3 generations a year, and adults survive the winter in weeds, under plant residues, in soil clods and soil seams.

Control method: when the population density of the overwintering generation is large from May to June, 4.5% trichlorfon powder and 2.5% trichlorfon powder are used to control it, about 2.5kg per mu. In the peak period, contact with 2.5% deltamethrin 2000-4000 times spray. Before overwintering, the residual branches and leaves in the field should be removed, the source of overwintering insects should be killed by irrigation and other methods, so as to reduce the survival rate of overwintering, so as to achieve the purpose of control.

Ceroplastes przewalskii

This insect is a piercing pest in the root of Glycyrrhiza uralensis. In addition to seriously harming wild licorice, it is destructive in artificially cultivated licorice in Inner Mongolia, Ningxia and Gansu. The insect has a generation of one year and overwinters as newly hatched nymphs in the host rhizosphere. In its life history, only the adult stage is briefly active on the ground, and all other stages live underground. The main damage period is from early May to early August every year, and the spherical red beads covered with wax shell can be seen on the host rhizome during the damage period. Because the damage period is early and underground, it is not easy to be found, and it is difficult to prevent and cure. Often, the rhizomes rot and a large number of plants die.

Control methods: the best period for chemical control is the host-seeking period of overwintering nymphs from late March to early May and the mating and spawning period of adults from early August to late August. In the early stage, internal absorption insecticides can be used to open ditches and irrigation, and in the later stage, powder spraying and spray contact can be used to achieve better control effects. Attention should be paid to the selection of habitat types in artificial cultivation in order to avoid destructive damage. Timely and reasonable mining of licorice is also one of the important methods to prevent the loss of insect pests.

Leafhopper

Mainly elm leafhopper, small green leafhopper and so on, mainly harmful to licorice leaves. Licorice is distributed in all producing areas with a large number of fields with long harmful period and serious harm, the lower functional leaves of the plant wither and fall off ahead of time, and the middle and upper functional leaves change from green to yellow, which seriously affects the growth and can lead to the dormancy of fallen leaves one month ahead of schedule. The serious damage period was from mid-June to mid-August, and licorice began to wither and yellow after September, which showed that licorice obviously moved to other hosts to overwinter. The insect has 4-5 generations in a year and overwinters with eggs in the cracks in the bark and between the branches. The damage of this insect can be seen in the growing period of licorice.

Control methods: experiments showed that the control effects of 1000, 2500 and 5000 times of 2.5% deltamethrin emulsion and 45kg per mu were 96.6%, 97.9% and 95.3% respectively 14 hours after application, and 2000-4000 times solution could be used in production. In order to prevent insect pests, the cultivation of licorice should avoid excessive water and fertilizer, plant green and crazy growth, and remove elm and other overwintering hosts.

Aphids

Mainly for black aphid, peach aphid and so on. The insect is widely distributed and occurs for 8 to 12 generations a year. It overwinters with eggs in branches and crevices of trees, as well as in the rhizosphere of perennials. The damage degree varies greatly in different years and different habitats, usually the damage period is short, and individual plants are mostly damaged from late June to early July, but it is not easy to see in other periods.

Control methods: in general years, natural enemies such as ladybugs and lacewings can be used to control aphids, and there is no need to control them. At the same time, attention should be paid to the removal of weeds near fields and canals. In order to prevent and control aphids as soon as possible in years with serious damage, attention should be paid to the control ability of natural enemies eating aphids. Short-acting enemy killing, dimethoate, monocrotophos and so on are mainly used.

Short-haired weevil

The insect is a small green weevil that feeds on the stems and leaves of licorice. The damage period of this insect is long, which can be seen in licorice fields from May to September, and the peak period is from July to early August. The leaves are mainly eaten, and the leaf margin is notched after feeding. Two or three generations occur every year, overwintering with adults or first instar larvae in the cracks in the bark, licorice and weed rhizosphere. The occurrence of insect pests does not have strict requirements on humidity, and the relative humidity of 20% to 50% is conducive to reproduction.

Control method: 2.5% deltamethrin emulsion 1000, 2500, 5000 times, mu application of 45kg can achieve satisfactory control effect, the control effect is 98.0%, 91.8%, 88.3% respectively. In addition, the combination of weeding in autumn, destroying its overwintering place and lowering the overwintering base can also play a preventive role. To avoid planting under or near the forest belt in the development of licorice production is a way to reduce the harm of pests such as short-haired weevil.

Blind bug

There are mainly forage bugs, three-spot bugs, alfalfa bugs, etc., which occur for 3 to 4 generations a year. Forage bugs overwinter as adults in the host rhizosphere of weeds, bark cracks and litter in the field. Other blind bugs overwinter with eggs in the residual branches and bark cracks of hosts such as licorice and alfalfa. Licorice is distributed in all producing areas, and the peak damage period is from July to early August. The damage symptoms are similar to those of leafhoppers, but the white spots are larger, and most of the leaves are silver-white and green, which often occur mixed with leafhoppers. Attention should be paid to the management of density, water and fertilizer in cultivation to prevent the habitats from causing outbreaks and disasters.

Control methods: remove the residual branches and leaves in and around the field in autumn and winter, remove weeds in time at the end of spring, at the same time strict water and fertilizer management, properly thinning seedlings to make plant growth robust and reduce the occurrence of insect pests. When the insect population is too large, conventional pesticides together with leafhoppers can be used for once control.

Licorice bean elephant

The insect produces one generation a year, overwinters as larvae in licorice seeds, and begins Eclosion in late May. It mainly feeds on licorice seeds during storage, and adults can also eat licorice leaves. If the seeds are not treated in that year, the decay rate can reach 35% after overwintering and 77.4% after 2 years of storage.

Control methods: field investigation showed that adults could be found in the field from late May to late September, and the population density was the highest in early August. The key points of control are podding stage (seed base) and seed storage period. The treatment of seeds in the storage period is convenient and efficient, and good results can be achieved by fumigation with aluminum phosphide or seed storage with armor powder and 165 powder.

The larvae overwintered in dead branches.

Control methods: pay attention to weeding before winter, eliminate the source of overwintering insects and remove the damaged plants in time.

Underground pest

In addition to the above-mentioned aboveground pests, the key to the rapid development of licorice production and obtain good economic benefits lies in the control of underground pests. In addition to Ningxia carmine scale, there are mole cricket and he's oriental chelate beetle in the emergence stage, and there are mainly black wrinkle Gill beetle, yellow brown beetle, golden needle beetle, grub, ground tiger, pseudo-beetle and so on that seriously harm the production of licorice.

There is a great difference in loss between wild licorice and artificially cultivated licorice after being damaged by underground pests. The wild root head is deep from the surface, and the main part of feeding harm is the underground stem. After the damage, the adventitious buds can grow rapidly and regenerate, so that the whole plant will not rot and die. The root is the main harm to cultivated licorice, and the young recovery ability of the plant is weak, which often leads to the decay and death of the whole plant along with decay and infection. Therefore, it is difficult to protect seedlings in artificial cultivation of licorice for 1 ~ 3 years. This is the main reason for the lack of seedlings and death of large-scale cultivated licorice caused by underground pests such as tobacco carmine scale and grub in Ningxia.

Control methods: habitats and areas where underground pests are light and not conducive to occurrence should be selected before ① sowing. ② fine soil preparation, deep ploughing heavy rake, destroy its habitat, kill insects. ③ applied rotten stable manure to prevent grubs from being brought into licorice field. ④ attaches importance to germination and seed treatment before sowing, and seeds can be mixed with 40% isofloxamate 0.2% (seed weight), 50% 1605 EC 0.2%, 25% phoxim 0.1% and so on. ⑤ in the case of large population of underground pests, 2% phoxim powder 5kg is sprayed on the front mu of cultivated land, and the soil can also be treated with armor powder and 1605 powder before sowing. ⑥ 3-year-old licorice was picked in time.

In order to meet the quality standard of pollution-free medicinal materials, it is forbidden to spray toxic pesticides or other chemicals within 45 to 60 days before licorice harvest to prevent pesticides or harmful heavy metals from exceeding the standard.