Cassava tetranychus cinnabarinus green control method

Abstract

The invention discloses a green prevention and control method for cassava tetranychus cinnabarinus. The prevention and control method mainly comprises the following steps: (1) agricultural prevention and control: (1) field cleaning, (2) deep ploughing and ridge drying, (3) reasonable fertilization, (4) selection of resistant varieties, (5) scientific irrigation, and (6) reasonable intercropping or crop rotation; (2) physical prevention and control: trapping and killing by using an insect trapping plate and covering by using a plastic film; (3) biological prevention and control: (1) protecting and utilizing natural enemies and (2) releasing predatory mites; and (4) green medicament prevention and treatment: performing emergency prevention and treatment by using a biological medicament in the early peak period of the cassava tetranychus cinnabarinus. According to the occurrence rule of tetranychus cinnabarinus, economic, simple, safe and effective coordinated application of agricultural fitness cultivation and environment-friendly measures such as ecological regulation and control, biological prevention and control, physical prevention and control and precise target of green agents are adopted according to local conditions to control the tetranychus cinnabarinus of cassava, so that the tetranychus cinnabarinus is expected to be controlled below a certain economic threshold value; economic benefits of cassava production are guaranteed, and healthy, efficient and sustainable production of the cassava industry is promoted.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural pest control, and in particular relates to a method for controlling cassava spider mites. Background Art

[0002] Cassava cultivation is an important part of agricultural economic development in tropical areas of my country, with a planting area of ​​about 560,000 hm2. 2 , with an annual output of about 10 million tons of fresh cassava, but it is far from meeting the needs of the domestic industry. my country is the world's largest consumer of cassava and the largest importer of cassava (including fresh cassava, cassava chips and cassava starch), and more than 70% of cassava raw materials are imported. Guangxi is an important base for cassava planting and processing in my country, with a planting area and output accounting for more than 60% of the country. It is also the largest cassava starch and alcohol production base in my country.

[0003] However, cassava is facing the real harm of Tetranychus cinnabarinus at all stages of its growth, which has become an important limiting factor restricting the sustainable and healthy development of Guangxi's cassava industry. Tetranychus cinnabarinus is a worldwide agricultural pest mite that feeds on more than 100 different plants and has a wide range of hosts. It often gathers on the back of leaves and sucks cell sap along the veins, causing the leaves to fade and yellow, gradually losing their photosynthetic capacity, and thus leading to a decrease in crop yields. Due to its small size, strong reproductive capacity, fast development, short generation, serious generation overlap, strong environmental adaptability and concealment, cinnabarinus mites are prone to drug resistance, making them difficult to control. Preliminary surveys found that cassava planting areas in Wuming, Guiping, Tiandeng, Longan and other places in Guangxi are all affected by Tetranychus cinnabarinus. Mite damage can cause cassava production to decrease by 20% to 30%, and in severe cases, by 50% to 80%, or even a total loss. Mite damage has become one of the important factors restricting the growth of cassava production in Guangxi. Dry and high temperature climate conditions are conducive to the development of spider mites. In recent years, due to the influence of abnormal global climate changes, regional and seasonal high temperature and drought climates have frequently occurred. Cassava is frequently harmed by spider mites during the growth period, which poses a serious threat to the yield and quality of cassava. Although rainfall can help alleviate the mite situation, excessive rainfall can also cause a reduction in cassava production. At the same time, due to the lack of technical guidance for farmers, it is difficult to form effective treatment measures for the damage caused by spider mites. Therefore, how to effectively prevent and control the occurrence and damage of spider mites has become a major issue that needs to be solved in the healthy and sustainable development of my country's cassava industry.

[0004] In recent years, with the adjustment of the planting industry structure and the influence of climatic conditions, cassava spider mites have continued to occur and cause serious damage. There is no complete set of technical specifications from prediction to prevention and control, resulting in unreasonable selection of prevention and control periods, prevention and control indicators, and prevention and control agents, which has increased the resistance of cassava spider mites to pesticides and increased the use of chemical pesticides. The large-scale use of chemical agents seriously threatens human health, and it is also easy to cause the insect to develop resistance to pesticides, kill natural enemies by mistake, and pollute the environment. In order to better control the large-scale spread and harm of spider mites and effectively control their populations before an outbreak, it is urgent to establish green control technical regulations for the insect as a theoretical and practical guide. Summary of the invention

[0005] In view of the above problems, the present invention provides a green control method for cassava spider mites, which adopts a method that combines agricultural control, physical control, biological control and green agent control to reduce the problem of over-reliance on chemical pesticides in traditional methods, and achieves a more green and environmentally friendly control effect while ensuring that the spider mites are effectively controlled.

[0006] The present invention is achieved through the following technical solutions:

[0007] A green control method for cassava spider mites comprises the following steps:

[0008] (1) Agricultural prevention and control

[0009] ① Clean the fields:

[0010] After the last cycle of cassava harvest, the field stumps and leaves were removed and the remaining cassava straw was treated comprehensively to destroy the habitat of the cinnabarinus spider mite and reduce the insect source base number;

[0011] Before planting cassava in spring, weeds should be removed from the edge of the field, and residual branches and leaves should be cleared to reduce the insect population base;

[0012] After planting cassava, timely weeding and weeding should be carried out according to soil moisture conditions to remove weeds in the field, on the edge of the field, and on the edge of the ditch. At the same time, the weeds should be removed from the cassava field to reduce intermediate hosts.

[0013] In the cassava seedling stage, the damage of spider mites is relatively light, the damaged leaves are scattered, and the mite damage rate is below 5%. The mite-infected leaves should be removed in time and taken out of the field and buried deep. This will prevent spider mites from transferring to other leaves to a certain extent, reduce the insect population base, and avoid the large-scale spread of spider mites.

[0014] ② Deep ploughing and sun-drying: Before planting cassava, clean the field thoroughly, plow deeply and dry the ridges. The tillage depth is 30 to 40 cm, and the number of days for sun-drying the ridges is 15 to 30 days.

[0015] ③ Reasonable fertilization: Apply enough cassava base fertilizer, more organic fertilizer or bacterial fertilizer, and more phosphorus fertilizer to cultivate strong seedlings and improve the resistance of cassava to cinnabar spider mites. 2 Apply 500-800kg of organic fertilizer, 50-60kg of phosphate fertilizer and 30-40kg of compound fertilizer (15-15-15);

[0016] ④Select resistant varieties: Select medium-resistant and above varieties to improve the resistance of cassava itself;

[0017] ⑤Scientific irrigation: After cassava is planted, water management should be strengthened, and in hot and dry weather, appropriate irrigation should be used to increase field humidity and promote cassava growth;

[0018] ⑥ Reasonable intercropping or crop rotation

[0019] Reasonable intercropping of cassava with agar grass or sweet potato crops can improve the ecological microenvironment of cassava planting areas, provide favorable conditions for the survival and proliferation of natural enemies of harmful mites, and inhibit the outbreak of harmful mites;

[0020] Implementing a crop rotation system can alleviate soil obstacles to continuous cropping, keep the soil healthy and cultivate strong seedlings, thus enhancing the growth potential of cassava and improving its resistance to mites;

[0021] (2) Physical prevention

[0022] ① Insect trapping: In the cassava seedling stage, when spider mites migrate into farmland in April and May to cause damage, hang yellow and / or blue boards between cassava rows to trap and kill spider mites;

[0023] ② Film covering: Use silver and black double-color film for covering, with the silver side facing upward to repel pests and the black side facing downward to prevent weeds, and cover tightly with soil on all sides; effectively reduce the evaporation of soil moisture, conserve soil moisture during droughts and increase soil moisture after rains, improve soil fertility, reduce weed growth, ensure uniform and strong cassava seedlings, and reduce diseases and insect pests;

[0024] (3) Biological control

[0025] ① Protect and utilize natural enemies: Protect or plant plants that support natural enemies on the ridges of fields, and try to avoid spraying broad-spectrum insecticides and miticides during the breeding season and peak activity period of natural enemies, provide food and habitats for natural enemies, and fully protect and utilize natural enemies to control the population of cinnabarinus spider mites;

[0026] ② Release predatory mites: If conditions permit, artificially introduce, breed, and release predatory mites for prevention and control;

[0027] (5) Green pesticide control

[0028] In the early stage of the damage, when the cinnabarinus spider mite occurs in patches, that is, when the mite damage rate is less than 25%, choose Beauveria bassiana or botanical insecticides for prevention and control; when the damage is serious, when the mite damage rate is ≥25%, take chemical agents for emergency prevention and control as soon as possible;

[0029] When implementing chemical control, pay attention to the rotation of different types of agents to prevent and delay the development of drug resistance; when spraying, focus on the back of cassava leaves to improve the control effect.

[0030] As a preferred technical solution, the comprehensive treatment of cassava straw is to crush the straw and return it to the field, bury the straw in the field through deep plowing, and then treat it in combination with ridge drying.

[0031] As a preferred technical solution, in step (1) agricultural control, the resistant variety is selected from Huanan 9 (resistant), Nanzhi 199 (medium resistant) or Huanan 5 (medium resistant). Selecting resistant varieties is the most economical and effective measure for controlling spider mites.

[0032] As a preferred technical solution, in step (1), cassava and agar-agar grass are intercropped in a row ratio of 2:3-4; cassava and sweet potato are intercropped in a row ratio of 2:3-4.

[0033] As a preferred technical solution, in step (2) of physical control, the insect trap board is yellow or blue, and the number of insect trap boards is 667m 2 Hang 30 to 50 sheets; hang them in the lower middle part of the cassava plant, 20 to 30 cm above the ground.

[0034] As a preferred technical solution, in step (3) biological control, the natural enemy plants are Cnidium monnieri, Cosmos chrysanthemum, etc.; natural enemies include predatory mites, mite-eating ladybugs, spiders, thrips and lacewings, etc.

[0035] As a preferred technical solution, in step (3), the predatory mites include Phytoseiulus chilensis, Amblyseius cucumeris, Amblyseius nissoni and Amblyseius pseudo-pilosei.

[0036] As a preferred technical solution, in step (4), the amount of Beauveria bassiana is 1×10 6 ~1×10 8 CFU / mL; botanical insecticides were selected from 1,000-fold dilution of 0.3% azadirachtin emulsifiable concentrate, 500-fold dilution of 0.5% veratrine alcohol soluble solution, or 1,000-fold dilution of 0.2% matrine aqueous solution;

[0037] As a preferred technical solution, the chemical agent in step (4) is selected from 5,000 times diluted 5.7% emamectin benzoate water dispersible granules, 3,000 times diluted 3.2% chlorfenapyr·emamectin benzoate microemulsion, 2,000 times diluted 20% avermectin·insecticidal monomicroemulsion, 2,000 times diluted 4.5% highly effective cypermethrin microemulsion, or 2,000 times diluted 2.5% highly effective chlorfenapyr water emulsion for spraying control.

[0038] The beneficial effects of the present invention are:

[0039] (1) The present invention aims to control the pest of cinnabarinus spider mites in cassava cultivation, which leads to a significant reduction in cassava yield. From the perspective of protecting ecology, the present invention coordinates and applies environmentally friendly measures such as agricultural prevention and control, ecological regulation, physical prevention and control, biological prevention and control, and scientific use of drugs according to local conditions to control the pest of cinnabarinus spider mites on cassava.

[0040] (2) The present invention carries out field cleaning after cassava is harvested and before planting to prevent and control and reduce the hosts of spider mites, thereby controlling the insect population base. The present invention also combines deep plowing, sunning ridges, reasonable fertilization, reasonable intercropping or crop rotation to enhance the resistance of cassava to spider mites. Compared with monocropping, the mite damage rate of cassava intercropping can be reduced by 7-8%. Although the cassava yield of intercropping is lower than that of monocropping, certain economic benefits can be obtained after the intercropping of agar-agar grass is harvested, and the net income of intercropping is about 48% higher than that of monocropping.

[0041] (3) Compared with conventional planting, the mite damage rate can be reduced by 35-44% by using the method of the present invention to plant cassava, and the cassava yield can be increased, thereby achieving the effect of reducing the use of traditional chemical agents. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a flow chart of the control method of the present invention.

[0043] Figure 2 The growth status diagram of cassava seedlings in film-covered and non-film-covered planting. Figure A is the growth status diagram of film-covered planting, and Figure B is the growth status diagram of non-film-covered planting.

[0044] Figure 3 This is a growth diagram of cassava plants without film covering. Weaker cassava plants are more seriously damaged by spider mites, while stronger cassava plants are less damaged by spider mites.

[0045] Figure 4 The left picture shows cassava monoculture and cassava intercropped with jelly grass, which are damaged by spider mites. The right picture shows cassava monoculture and the left picture shows cassava intercropped with jelly grass.

[0046] Figure 5 This is an experiment to control cassava spider mites by hanging insect traps of different colors and at different hanging heights. DETAILED DESCRIPTION

[0047] The present invention is further described in detail below by way of examples. These examples are only used to illustrate the present invention and do not limit the protection scope of the present invention.

[0048] Example 1

[0049] The green control method of cinnabarinus spider mite in cassava monoculture includes the following steps:

[0050] (1) Agricultural prevention and control

[0051] ① Clean the fields:

[0052] In January 2022, an experiment was carried out in cassava planting areas in Longzhou County, Chongzuo City, Guangxi. After cassava was harvested, the dead plants and leaves in the field were cleared, the remaining cassava straw was crushed and returned to the field, and deep plowing was used to bury the straw in the field. The field was then treated with ridge drying to destroy the suitable habitat of the cinnabarin spider mite and reduce the insect source base.

[0053] In February 2023, before cassava planting in spring, weed the field edges and remove remaining branches and leaves to reduce the insect population base;

[0054] After planting cassava, timely weeding and weeding should be carried out according to soil moisture conditions to remove weeds in the field, on the edge of the field, and on the edge of the ditch. At the same time, the weeds should be removed from the cassava field to reduce intermediate hosts.

[0055] During the cassava seedling stage, the damage caused by cinnabar spider mites is relatively light and the affected leaves are sparsely distributed. When the mite damage rate is below 5%, the mite-infected leaves should be removed in time and taken out of the field and buried deeply. This will prevent the spider mites from transferring to other leaves to a certain extent, reduce the insect population base, and avoid the large-scale spread of cinnabar spider mites.

[0056] ② Deep plowing and sun-drying: Before planting cassava, clean the field thoroughly, deep plow and sun-dry the ridges. The plowing depth is 30 to 40 cm, and the ridges are sun-dried for 15 to 30 days.

[0057] ③ Reasonable fertilization: Apply enough cassava base fertilizer, more organic fertilizer or bacterial fertilizer, and more phosphorus fertilizer to cultivate strong seedlings and improve the resistance of cassava to cinnabar spider mites. 2 Apply 500-800kg of organic fertilizer, 50-60kg of phosphate fertilizer and 30-40kg of compound fertilizer (15-15-15);

[0058] ④ Select resistant varieties: According to planting needs, choose Nanzhi 199 (medium resistance) for planting to improve the resistance of cassava itself.

[0059] ⑤Scientific irrigation: After cassava is planted, water management should be strengthened, and in hot and dry weather, appropriate irrigation should be used to increase field humidity and promote cassava growth;

[0060] (2) Physical prevention

[0061] ① Film covering: Use silver and black double-color film to cover cassava during planting, with the silver side facing upwards to repel pests and the black side facing downwards to prevent weeds. Seal the ground tightly with soil on all sides. This can effectively reduce the evaporation of soil moisture, conserve moisture during droughts and increase moisture after rains, improve soil fertility, reduce weed growth, ensure that cassava seedlings are uniform and strong, and reduce diseases and insect pests.

[0062] ② Insect trapping: When cassava seedlings are in the stage and spider mites migrate into farmland to cause damage, yellow or blue boards are hung between cassava rows to trap spider mites. 2 Hang 30 sheets; hang them in the lower middle part of the cassava plant, 20 to 30 cm above the ground.

[0063] (3) Biological control

[0064] ① Protect and utilize natural enemies: Protect or plant plants that can conserve natural enemies, such as Cnidium monnieri and Cosmos, on the ridges of fields, and try to avoid spraying broad-spectrum insecticides and acaricides during the breeding season and peak activity period of natural enemies, provide food and habitats for natural enemies, and fully protect and utilize natural enemies to control the population size of cinnabarin spider mites; the natural enemies of cinnabarin spider mites include predatory mites, mite-eating ladybugs, spiders, thrips and lacewings.

[0065] ② Release predatory mites: If conditions permit, artificially introduce, breed and release predatory mites for prevention and control. Predatory mites include Phytoseiidae Chileensis, Amblyseiidae Cucurbita, Amblyseiidae Nissoni and Amblyseiidae Pseudohair Mite.

[0066] (4) Green pesticide control

[0067] In the early stage of the damage, when the cinnabarinus spider mite occurs in patches, that is, when the mite damage rate is less than 25%, Beauveria bassiana is selected for spraying control; the dosage of Beauveria bassiana is 1×10 6 ~1×10 8 CFU / mL; according to the situation, spray with botanical insecticides. Botanical insecticides can be 1,000 times diluted 0.3% azadirachtin emulsifiable concentrate, 500 times diluted 0.5% veratrine alcohol soluble liquid, or 1,000 times diluted 0.2% matrine aqueous solution.

[0068] When the infestation is serious and the mite damage rate is ≥25%, chemical agents should be used for emergency prevention and control as soon as possible; chemical agents can be selected from 5,000 times diluted 5.7% emamectin benzoate water-dispersible granules, 3,000 times diluted 3.2% perchlorate·emamectin benzoate microemulsion, 2,000 times diluted 20% avermectin·insecticidal monomicroemulsion, 2,000 times diluted 4.5% highly effective cypermethrin microemulsion, or 2,000 times diluted 2.5% highly effective chlorfenapyr emulsion in water for spray control.

[0069] When implementing chemical control, pay attention to the rotation of different types of agents to prevent and delay the development of drug resistance; when spraying, focus on the back of cassava leaves to improve the control effect.

[0070] Example 2

[0071] A green control method for cassava spider mites comprises the following steps:

[0072] (1) Agricultural prevention and control

[0073] ① Clean the fields:

[0074] In January 2021, after the cassava was harvested in the previous cycle, the stumps and leaves in the field were cleared, the remaining cassava straw was crushed and returned to the field, deep plowing was carried out to bury the straw in the field, and then the field was treated by ridge drying to destroy the suitable habitat of the cinnabarin spider mite and reduce the insect source base.

[0075] Before planting cassava in February 2022, weeds will be removed from the edge of the field and remaining branches and leaves will be cleared to reduce the insect population base;

[0076] After planting cassava, timely weeding and weeding should be carried out according to soil moisture conditions to remove weeds in the field, on the edge of the field, and on the edge of the ditch. At the same time, the weeds should be removed from the cassava field to reduce intermediate hosts.

[0077] When the damage caused by cinnabar spider mites is relatively light and the affected leaves are sparsely distributed, and the mite damage rate is below 5%, the mite-infected leaves should be removed in time and taken out of the field and buried deeply. This will prevent the spider mites from transferring to other leaves to a certain extent, reduce the insect population base, and avoid the large-scale spread of cinnabar spider mites.

[0078] ② Deep plowing and sun-drying: Before planting cassava, clean the field thoroughly, deep plow and sun-dry the ridges. The plowing depth is 30 to 40 cm, and the ridges are sun-dried for 15 to 30 days.

[0079] ③ Reasonable fertilization: Apply enough cassava base fertilizer, more organic fertilizer or bacterial fertilizer, and more phosphorus fertilizer to cultivate strong seedlings and improve the resistance of cassava to cinnabar spider mites. 2 Apply 500-800kg of organic fertilizer, 50-60kg of phosphate fertilizer and 30-40kg of compound fertilizer (15-15-15);

[0080] ④ Select resistant varieties: According to planting needs, choose Nanzhi 199 (medium resistant) and Huanan for planting. Choose medium resistant and above varieties to improve the resistance of cassava itself.

[0081] ⑤Scientific irrigation: After cassava is planted, water management should be strengthened, and in hot and dry weather, appropriate irrigation should be used to increase field humidity and promote cassava growth;

[0082] ⑥ Reasonable intercropping or crop rotation

[0083] Before planting, intercrop cassava and agar grass in a 2:4 ratio to improve the ecological microenvironment of the cassava planting area, provide favorable conditions for the survival and proliferation of natural enemies of harmful mites, and inhibit the outbreak of harmful mites. Figure 4 shown.

[0084] (2) Physical prevention

[0085] ① Ground film covering: When planting cassava, use silver and black double-color ground film for covering, with the silver facing upwards to repel pests, and the black facing downwards to prevent weeds, and seal the surrounding area with soil.

[0086] ② Insect trapping: When cassava seedlings are in the stage and spider mites migrate into farmland to cause damage, yellow or blue boards are hung between cassava rows to trap spider mites. 2 Hang 30 sheets; hang them in the lower middle part of the cassava plant, 20 to 30 cm above the ground.

[0087] (3) Biological control

[0088] ① Protect and utilize natural enemies: Protect or plant plants that can conserve natural enemies, such as Cnidium monnieri and Cosmos, on the ridges of fields, and try to avoid spraying broad-spectrum insecticides and acaricides during the breeding season and peak activity period of natural enemies, provide food and habitats for natural enemies, and fully protect and utilize natural enemies to control the population size of cinnabarin spider mites; the natural enemies of cinnabarin spider mites include predatory mites, mite-eating ladybugs, spiders, thrips and lacewings.

[0089] ② Release predatory mites: If conditions permit, artificially introduce, breed and release predatory mites for prevention and control. Predatory mites include Phytoseiidae Chileensis, Amblyseiidae Cucurbita, Amblyseiidae Nissoni and Amblyseiidae Pseudohair Mite.

[0090] (4) Green pesticide control

[0091] In the early stage of the damage, when the cinnabarinus spider mite occurs in patches, that is, when the mite damage rate is less than 25%, Beauveria bassiana is selected for spraying control; the dosage of Beauveria bassiana is 1×10 6 ~1×10 8 CFU / mL; according to the situation, spray with botanical insecticides. Botanical insecticides can be 1,000 times diluted 0.3% azadirachtin emulsifiable concentrate, 500 times diluted 0.5% veratrine alcohol soluble liquid, or 1,000 times diluted 0.2% matrine aqueous solution.

[0092] When the infestation is serious and the mite damage rate is ≥25%, chemical agents should be used for emergency prevention and control as soon as possible; chemical agents can be selected from 5,000 times diluted 5.7% emamectin benzoate water-dispersible granules, 3,000 times diluted 3.2% perchlorate·emamectin benzoate microemulsion, 2,000 times diluted 20% avermectin·insecticidal monomicroemulsion, 2,000 times diluted 4.5% highly effective cypermethrin microemulsion, or 2,000 times diluted 2.5% highly effective chlorfenapyr emulsion in water for spray control.

[0093] When implementing chemical control, pay attention to the rotation of different types of agents to prevent and delay the development of drug resistance; when spraying, focus on the back of cassava leaves to improve the control effect.

[0094] Comparative Example 1

[0095] The traditional cassava monoculture method differs from Example 1 only in that the physical control method of step (2) is not used, the planting plot is not covered with mulch, and insect traps are not used for killing insects. In the biological control process of step (3), natural enemy plants are not planted intentionally. No predatory mite release operation is carried out. Figure 3 shown.

[0096] In Examples 1-2 and Comparative Example 1, referring to the survey method and leaf damage classification standard of "NY / T 2445-2013 Technical Regulations for Identification of Insect Resistance of Cassava Germplasm Resources", 10 cassava plants in different planting directions (east, west, south, north, and center) were randomly sampled for mite damage investigation, totaling 50 cassava plants, and 4 most severely damaged cassava leaves were selected from the upper, middle, and lower parts of each plant for investigation, and a total of 12 leaves were investigated for each plant, and the number of damaged plants, the total number of investigated plants, the damage level of each leaf, and other data were recorded, and the mite damage rate and mite damage index were calculated. The implementation effect is recorded in Table 1.

[0097] Table 1 Comparison of the control effect of Tetranychus cinnabarinus in different planting methods

[0098]

[0099] Note: The purchase price of fresh cassava is 840.00 yuan / t, and the purchase price of agar-agar grass hay is 11.00 yuan / kg.

[0100] Mite damage rate = number of plants with mites / total number of plants investigated × 100

[0101] Mite damage index:

[0102] Where: I, represents the mite damage index; S, leaf damage level; N S , the number of leaves at this damage level; N, the total number of leaves investigated.

[0103] It can be seen from Table 1 that: (1) When the method of the present invention is used, the mite damage rate of cassava monoculture is reduced by 35.89% and the net income is increased by 18.60% compared with the comparison example 1; the intercropping method is reduced by 43.37% and the net income is increased by 75.16% compared with the comparison example 1, which can effectively reduce the damage of cinnabar spider mites and increase the income of cassava planting.

[0104] (2) In the case of cassava monoculture, the damage of Tetranychus cinnabarinus can be effectively controlled and reduced by coordinating and applying agricultural prevention and control, ecological regulation, physical prevention and control, biological prevention and control, and scientific use of drugs according to local conditions. The mite damage rate of Example 1 was reduced by about 35% compared with that of Comparative Example 1, the fresh yam yield was increased by 26.47%, the net income was increased by 18.60%, and cassava production and income were effectively increased.

[0105] (3) Comparison between monoculture and intercropping of cassava. In Example 2, by intercropping cassava with agarwood, the mite damage rate can be reduced by 7-8%, indicating that intercropping is beneficial to the prevention and control of the damage of spider mites. Although the cassava yield of intercropping is lower than that of monoculture, intercropped crops are cash crops and can also obtain certain economic benefits after harvest. The net income of intercropping is 47.68% higher than that of monoculture.

[0106] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A green control method for cassava spider mites, characterized in that: The following steps are involved: (1) Agricultural prevention and control ① Clean the countryside: After the last cycle of cassava harvest, the field stumps and leaves were removed and the remaining cassava straw was treated comprehensively to destroy the habitat of the cinnabarinus spider mite and reduce the insect source base number; Before planting cassava in spring, weeds should be removed from the edge of the field, and residual branches and leaves should be cleared to reduce the insect population base; After planting cassava, timely weeding and weeding should be carried out according to soil moisture conditions to remove weeds in the field, on the edge of the field, and on the edge of the ditch. At the same time, the weeds should be removed from the cassava field to reduce intermediate hosts. In the cassava seedling stage, the damage of spider mites is relatively light, the damaged leaves are scattered, and the mite damage rate is below 5%. The mite-infected leaves should be removed in time and taken out of the field and buried deep. This will prevent spider mites from transferring to other leaves to a certain extent, reduce the insect population base, and avoid the large-scale spread of spider mites. ② Deep ploughing and sun-drying: Before planting cassava, clean the field thoroughly, plow deeply and dry the ridges. The tillage depth is 30 to 40 cm, and the number of days for sun-drying the ridges is 15 to 30 days. ③ Reasonable fertilization: Apply enough cassava base fertilizer, more organic fertilizer or bacterial fertilizer, and more phosphorus fertilizer to cultivate strong seedlings and improve the resistance of cassava to cinnabar spider mites. 2 Apply 500-800kg of organic fertilizer, 50-60kg of phosphate fertilizer and 30-40kg of compound fertilizer; ④Select resistant varieties: Select medium-resistant and above varieties to improve the resistance of cassava itself; ⑤Scientific irrigation: After cassava is planted, water management should be strengthened, and in hot and dry weather, appropriate irrigation should be used to increase field humidity and promote cassava growth; ⑥ Reasonable intercropping or crop rotation Reasonable intercropping of cassava with agar grass or sweet potato crops can improve the ecological microenvironment of cassava planting areas, provide favorable conditions for the survival and proliferation of natural enemies of harmful mites, and inhibit the outbreak of harmful mites; Implementing a crop rotation system can alleviate soil obstacles to continuous cropping, keep the soil healthy and cultivate strong seedlings, thus enhancing the growth potential of cassava and improving its resistance to mites; (2) Physical prevention ① Insect trapping: In the cassava seedling stage, when spider mites migrate into farmland in April and May to cause damage, hang yellow and / or blue boards between cassava rows to trap and kill spider mites; ② Film covering: Use silver and black double-color film for covering, with the silver side facing upward to repel pests and the black side facing downward to prevent weeds, and cover tightly with soil on all sides; effectively reduce the evaporation of soil moisture, conserve soil moisture during droughts and increase soil moisture after rains, improve soil fertility, reduce weed growth, ensure uniform and strong cassava seedlings, and reduce diseases and insect pests; (3) Biological control ① Protect and utilize natural enemies: Protect or plant plants that support natural enemies on the ridges of fields, and try to avoid spraying broad-spectrum insecticides and miticides during the breeding season and peak activity period of natural enemies, provide food and habitats for natural enemies, and fully protect and utilize natural enemies to control the population of cinnabarinus spider mites; ② Release predatory mites: If conditions permit, artificially introduce, breed, and release predatory mites for prevention and control; (4) Green pesticide control In the early stage of the damage, when the cinnabarinus spider mite occurs in patches, that is, when the mite damage rate is less than 25%, choose Beauveria bassiana or botanical insecticides for prevention and control; when the damage is serious, when the mite damage rate is ≥25%, take chemical agents for emergency prevention and control as soon as possible; When implementing chemical control, pay attention to the rotation of different types of agents to prevent and delay the development of drug resistance; when spraying, focus on the back of cassava leaves to improve the control effect.

2. The green control method for cassava spider mites according to claim 1, characterized in that: In step (1), the comprehensive treatment of cassava straw is to crush the straw and return it to the field, bury the straw in the field by deep plowing, and then treat it in combination with ridge drying.

3. The green control method for cassava spider mites according to claim 1, characterized in that: In step (1) agricultural control, the resistant variety is selected from Huanan 9, Nanzhi 199 or Huanan 5.

4. The green control method for cassava spider mites according to claim 3, characterized in that: In step (1), cassava and agar-agar grass are intercropped in a row ratio of 2:3-4; cassava and sweet potato are intercropped in a row ratio of 2:3-4.

5. The green control method for cassava spider mites according to claim 1, characterized in that: Step (2) In physical control, use yellow or blue traps, and place them every 667m 2 Hang 30 to 50 sheets; hang them in the lower middle part of the cassava plant, 20 to 30 cm above the ground.

6. The green control method for cassava spider mites according to claim 1, characterized in that: In step (3) biological control, the natural enemy plants are Cnidium monnieri and Cosmos chrysanthemum; natural enemies include predatory mites, mite-eating ladybugs, spiders, thrips and lacewings.

7. The green control method for cassava spider mites according to claim 1, characterized in that: In step (3), the predatory mites include Phytoseiulus chilensis, Amblyseius cucumeris, Amblyseius nissoni and Amblyseius pseudo-pilosula.

8. The green control method for cassava spider mites according to claim 6 or 7, characterized in that: In step (4), the amount of Beauveria bassiana is 1×10 6 ~1×10 8 CFU / mL; plant-based insecticides include 1,000-fold dilution of 0.3% azadirachtin emulsifiable concentrate, 500-fold dilution of 0.5% veratrine alcohol soluble liquid, or 1,000-fold dilution of 0.2% matrine aqueous solution.

9. The green control method for cassava spider mites according to claim 1, characterized in that: Step (4) The chemical agent is selected from 5,000 times diluted 5.7% emamectin benzoate water dispersible granules, 3,000 times diluted 3.2% emamectin benzoate microemulsion, 2,000 times diluted 20% avermectin benzoate microemulsion, 2,000 times diluted 4.5% highly effective cypermethrin microemulsion, or 2,000 times diluted 2.5% highly effective cyhalothrin water emulsion for spraying control.

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