Prevention and Control of insect pests of Glycyrrhiza uralensis L. in Ningxia

It is distributed in the producing areas of Glycyrrhiza uralensis all over the country, and it is generally harmful from seedling stage to adult stage. There are 8 species of host plants in Ningxia, all of which are perennial leguminous root plants. Licorice suffered the most, while other hosts suffered little.

① damage period and symptoms overwintering nymphs can move intermittently when the surface temperature reaches 6 ℃, and frequently when the daily average temperature exceeds 12 ℃ to find hosts. The early ten days of March was the initial active stage, the peak of host searching was in the middle and late ten days of April, and almost all settled in the middle of May. The pearl stage is from late May to late July (the main damage stage). The performance of licorice and other host plants is after the middle of June, the pearls gradually mature after late July, stop feeding damage, break away from the host and enter the metamorphosis stage.

The damage status of Glycyrrhiza uralensis varies greatly due to the population density of different habitats. The licorice field which was seriously injured last year sprouted late and grew weakly in the following year, some were difficult to sprout and green, the rhizome of the plant rotted, and the insect population density was also high in that year. In the seriously injured fields, the beads grew up and the food intake increased in the middle and late June. The damage aggravated and a large number of plants died, generally in the damaged field, the damage was not obvious from May to June, the lower leaves of the injured plants were withered and yellow after late June, or a large number of functional leaves in the middle and lower parts were scorched yellow, the leaf center was green and yellow, and reached the peak of damage after mid-July, the above damage was obvious, individual plants died, and the top leaves of the dead plants were wilt type. Since the first and middle of August, due to the aging and shedding of beads and stopping feeding, the growth of Glycyrrhiza uralensis tends to improve and stable, and some licorice obviously return to normal leaf color and growth.

When the parasite was dense, the root of Glycyrrhiza uralensis was in the shape of block, block and sleeve when it was embedded for a week, and the bead was in the shape of bead or tumor when it was evacuated. The former is more common in the main root, while the latter is more common in the string rhizome and lateral branch root.

② control timely early sowing, strengthen water, fertilizer and other field management, promote its growth robust and early, in order to enhance the ability of resistance to diseases and insect pests; for perennial licorice, deep ploughing heavy Harrow in June, mechanical killing of beads, loosening soil, promoting plant growth, enhancing insect resistance, digging licorice from June to July before beads are not mature, all beads die because they are separated from the host, which can greatly reduce the occurrence in the following year.

a. Pesticide control should focus on the application of pesticides in the adult stage and the active stage of the early instar nymphs after overwintering. The peak period of Eclosion should be mastered in the adult stage, and the pesticide should be applied for 1 or 2 times. Can use 4.5% of the enemy powder, 2.5~4kg per mu, or spray 2.5% of the enemy kill 3000 times the liquid. The killing effect on males is good, and the effect on females is more than 72%, and it can reduce the number of eggs laid and hatching rate, which has an aftereffect.

b. Early nymph control around mid-April, overwintering nymphs in the soil begin to move and look for hosts. 50% phoxim EC root can be applied, 0.5kg per mu, and ditches, pesticides, and soil can be opened before or after rain. If the soil is dry and there is no rain, the rhizosphere should be irrigated in shallow water after application to exert its efficacy.

Fumigation and control with aluminum phosphide: 3: 4 tablets per square meter (each tablet weighs 3.3 g), the application time is the same as above, and sealed with plastic film for 6 days at any time after application, there is no drug damage, and the effect is good.