The dry-based injection can be specialized for solid mother trees, which has the characteristics of saving manpower and material resources and not wasting liquid medicine. According to the amount of fertility increase or decrease the dosage, the effect is more obvious (Table 7-3). Table 7-3 Effect of dry-base injection on control of larch cone flies Liquid name Female tree breast diameter cm Infusion liquid volume ml Number of investigations 7-9 days larvae mortality Instructions 7 days 8 days 9 days Omethoate EC 40% 8 7 3 83 88 89 Daily survey of 1 dose on each site 10 8 3 74 74 78 12 9 3 81 86 87 14 11 3 87 88 88 16 13 3 91 92 95 18 15 3 94 96 97 Methamidophos 50% 8 7 3 93 95 95 10 8 3 94 94 94 12 9 3 86 87 87 14 11 3 82 84 86 16 13 3 91 94 94 18 15 3 90 91 93 average 12.66 10.5 3 87.1 89.8 90.3 (3) Forest management and prevention: In the Larix principis-rupprechtii orchards and mother trees, when the larvae are landed and defoliated, the method of removing weeds and litter from forest land is used to destroy the alfalfa overwintering environment. At the same time, the soil is combined with pressure greening and cultivating and weeding. Deep plowing and complete destruction of the wintering environment of the earthworm can significantly reduce the density of the insect population. In addition, there is a large width of the isolation belt around the orchard, which can effectively reduce the damage of the fly. III. Investigation and forecast of main pests of Larix principis-rupprechtii Investigation of pseud-resistance of North China larch is the basis for forecasting and forecasting. Predicting and forecasting is the basis of pest control and prevention, and it is the basis for implementing the principle of “prevention as the main, comprehensive treatmentâ€. Its task is: through the investigation and systematic observation of major pests, combined with the analysis of relevant data, accurately and timely forecast the occurrence period, amount, extent of occurrence and degree of damage of the North China larch pest, and put forward prevention opinions. (I) Fall Survey 1, autumn tune investigation (1) Time requirements: Completed from August to October. (2) Investigating the insect state: 1 Larch caterpillar: overwintering larvae; 2 Larch demoiselle: underground pupa; 3 Larch borer: underground overwintering prelimina; 4 Larch sheath moth: Overwintering larvae on the tree State; 5 Gypsy moth: Overwintering; 6 Larch cone flies: underground overwintering. (3) Surveying the number of plant strains: It can be determined by referring to Table 7-4 according to the small class area of ​​insect pests. Table 7-4 Determining the Number of Insect Pests to Be Determined Table Unit: Mu, strain Insect pests in small classes Occurrence area 100 or less 100―200 201~400 More than 400 Should investigate the number of samples 8 to 10 11～15 16-20 20 or more Casting Molding Machine,Sand Casting Molding Machine,Sand Molding Machine,Automatic Station Molding Equipment Changzhou Qiaojie Casting Equipment Co., Ltd. , https://www.qiaojieequipment.com