Method for preventing and controlling thrips by using stratiolaelaelalaelaps scimitus in seedling raising period of tobacco floating tray

Abstract

The invention discloses a method for preventing and controlling thrips by using stratiolaelaelalaelaps scimitus in a tobacco floating tray seedling raising period, which comprises the following steps: 1) arranging a seedbed in a leeward and sunny upper tuyere area, and cleaning thrip host plants around the seedbed; 2) dibbling two tobacco seeds in each hole of the seedling raising tray, then performing floating tray seedling raising, arranging 32 floating trays in each seedling shed, arranging the floating trays in a nutrient solution pool, adding tobacco floating seedling raising formula seedling fertilizer liquid into the nutrient solution pool, arranging a plurality of seedling sheds close to each other to form a seedling shed group, vertically arranging a plastic film around the seedling shed group, and arranging an insect-proof net around the seedling shed group; 3, seedling raising is carried out till the emergence rate of dibbling tobacco reaches 90% or above, thinning is carried out, 4-12 spreads of stratiolaelalaelaelata are scattered in root soil of plants on the floating seedling raising plate according to each seedling raising hole on the second day after thinning, and normal seedling raising management is carried out till the tobacco seedling transplanting period. By means of the method, thrips in soil, environment and leaves in the tobacco floating tray seedling raising period can be effectively prevented and controlled.

Description

Technical Field

[0001] The present invention relates to the technical field of tobacco seedling cultivation, in particular to a method for controlling thrips by using sword-haired handkerchief mites during tobacco floating tray seedling cultivation. Background Art

[0002] The healthy growth of tobacco seedlings is of great significance to the prevention and control of diseases and pests in the later stage and the high-quality and stable yield of tobacco leaves. Tobacco is vulnerable to thrips in the seedling stage, which is the main period and the best period for the prevention and control of tobacco thrips (CN201811375808.2). Western flower thrips and tobacco thrips are the two main thrips species that harm tobacco. These two thrips are also the main vectors of tobacco poisoning, posing a serious threat to the tobacco industry.

[0003] The main method of tobacco seedling cultivation is floating tray seedling cultivation. Tobacco floating seedling bed seedling cultivation refers to setting up multiple nutrient solution pools in the seedling shed, and floating multiple foam boards in the pools. Multiple grooves are set on the foam boards to accommodate the tobacco seedlings and their root substrates. The floating seedling trays float directly on the nutrient solution in the pools, relying on the capillary action and transpiration of the substrate to supply the nutrients and water required for seed germination and growth. This seedling cultivation method has the advantages of small footprint, high seedling cultivation efficiency, less substrate used, small exposed substrate area, which can reduce the living space of soil-borne diseases and pests, and high seedling success rate.

[0004] In order to prevent tobacco pests from attacking tobacco seedlings, it is often necessary to use insect-proof nets in the seedling shed. Due to the limited mesh diameter of ordinary insect-proof nets, they can only prevent pests such as aphids and whiteflies from entering, but have no effect on smaller thrips. If the mesh diameter of the insect-proof net used is too small, it will be difficult to ensure ventilation and air permeability in the seedling shed and above the seedbed, resulting in reduced seedling quality and survival rate.

[0005] As people pay more attention to the safety of tobacco leaf smoking, biological control methods are now widely used to control thrips in the tobacco seedling stage, that is, using predatory mites to prey on thrips, that is, using mites to control insects (such as CN201720932761.X). This method also plays a role in preventing thrips and the tomato spotted wilt disease they spread, and plays a source control role. For example, CN201811375808.2 discloses a method for controlling thrips in the tobacco seedling stage, in which the cucumber blunt mite is used as the control mite for thrips. The insect population reduction rate of this method for seedling thrips is 54.44%; the control effect on seedling thrips is 70.24%.

[0006] Stratiolaelaps scimitus is a fast-moving mite insect that lives on the soil surface. It is used to control fungus gnat larvae, thrips, springtails, putrescent tyrophagous mites, nematodes, etc. on crops such as vegetables, flowers and edible fungi.

[0007] The existing method of using sword-haired handkerchief laelaps to control thrips is: 7 to 10 days after the crop is planted, the occurrence of pest populations is monitored by color plates or visually observed. Once thrips are found, sword-haired handkerchief laelaps can be released for control. Currently, the biological control is mostly carried out by spreading sword-haired handkerchief laelaps at the roots of plants. The dosage of sword-haired handkerchief laelaps is 100 to 200 heads / m 2 At the same time, sprinkle 100-200 Neoseiulus pastoris or Neoseiulus cucurbitae / m on the leaves of the plants. 2 , release once every 2 weeks, and release 2-3 times in a row to improve the control effect.

[0008] The breeding and use environment requirements of the sword-haired handkerchief mite are: temperature 18-30℃, relative humidity 65-95% to ensure its activity and effect.

[0009] As can be seen from the above, the existing sword-haired handkerchief laelaps are mainly used for plant thrips control after planting, and this method is not necessarily suitable for tobacco seedling thrips control in the floating seedbed during the non-planting period. In addition, in the existing method of releasing sword-haired handkerchief laelaps, it is often necessary to release sword-haired handkerchief laelaps together with other mite insects at the same time to obtain a better control effect. The existing release method using only sword-haired handkerchief laelaps cannot obtain a better control effect; at the same time, studies have shown that sword-haired handkerchief laelaps need to live in the soil to prey on the mature larvae and pupae of western flower thrips that pupate in the soil. The tobacco seedling floating bed has a short seedling raising time and a small exposed soil area. The existing sword-haired handkerchief laelaps release method is difficult to ensure that it enters the soil in time to achieve timely killing of various types of mature larvae and pupae of thrips.

[0010] The information disclosed in the background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0011] The present application provides a method for controlling thrips with sword-haired hand mites during the tobacco floating tray seedling raising period, which is used to solve the technical problem of difficulty in controlling various forms of thrips in tobacco seedlings during the floating seedling bed period in the prior art.

[0012] The present application provides a method for controlling thrips with sword-haired handkerchief mites during the tobacco floating tray seedling raising period, comprising the following steps:

[0013] 1) Set up seedbeds in the upwind area that is leeward and sunny, and clear the host plants of thrips around the seedbeds;

[0014] 2) After planting 2 tobacco seeds in each hole of the seedling tray, floating tray seedlings are raised, 32 floating trays are set in each seedling shed, the floating trays are set in a nutrient solution pool, tobacco floating seedling formula fertilizer is added to the nutrient solution pool, multiple seedling sheds are set close to form a seedling shed group, plastic films are vertically set around the seedling shed group, and insect-proof nets are set around the seedling shed group;

[0015] 3) After the emergence rate of tobacco seedlings reaches more than 90%, thinning is carried out. On the second day after thinning, 4 to 12 sword-haired handkerchief mites are scattered in the root soil of the plants on the floating seedling tray at each seedling hole. Normal seedling management is carried out until the tobacco seedling transplanting period.

[0016] Preferably, thinning is performed so that only one relatively robust plant is retained in each hole.

[0017] Preferably, the number of seedling raising holes on the seedling raising tray used is 162 holes.

[0018] Preferably, the plastic film "vertically arranged around the seedling shed group" is a black or silver-black plastic film; and the bottom of the plastic film is arranged in close contact with the ground.

[0019] Preferably, the thrips host plants include at least Bidens pilosa, pepper, eggplant and various flowering plants.

[0020] Preferably, the method for removing thrips host plants includes: manual cleaning and spraying chemical pesticide agents.

[0021] Preferably, the spraying of chemical pesticide reagents is spraying at least one of spinetoram solution, imidacloprid solution and acetamiprid solution in a safe dosage.

[0022] Preferably, the range of thrips host plant removal is at least within 50m around the seedling shed group.

[0023] Preferably, the range of thrips host plant removal is within 50 to 100 m around the seedling shed group.

[0024] Preferably, the thrips host plant manipulation is carried out 10 days before tobacco sowing.

[0025] Preferably, the preparation method of the tobacco floating seedling formula fertilizer solution is as follows: first, water is added to the nutrient solution pool, and then the tobacco floating seedling formula fertilizer is added and stirred to dissolve.

[0026] The beneficial effects of this application include:

[0027] 1) The method for controlling thrips with sword-haired handkerchief mites during the tobacco floating tray seedling period provided in the present application can achieve effective control of thrips in the soil, environment, and leaves during the tobacco floating tray seedling period. The control effect of thrips in the soil such as thrips pupae is between 50% and 80%, and the average control effect is 66.81%; the control effect of thrips monitored by blue insect traps is between 30% and 60%, and the average control effect is 50.82%; the control effect of thrips investigated on leaves is between 30% and 80%, and the average control effect is 54.34%.

[0028] 2) The method for controlling thrips with sword-haired handkerchief mites during the tobacco floating tray seedling period provided in the present application can form a sword-haired handkerchief mites population in the soil of the seedling tray after the sword-haired handkerchief mites are released by this method, thereby achieving effective control of thrips during the seedling period. Moreover, this method only requires the use of sword-haired handkerchief mites to achieve a good control effect, indicating that this method can effectively improve the control of thrips during the tobacco floating tray seedling period by sword-haired handkerchief mites. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a line graph showing the statistical results of the number of Laelaps scaly-haired mites in Treatments 1 to 3 of Example 1 provided in the present application. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments, but the present invention is not limited in any way. Any changes or improvements made based on the teachings of the present invention fall within the protection scope of the present invention.

[0031] Example

[0032] Unless otherwise specified, the materials and instruments used in the following examples were obtained from commercial channels; the detection methods used were all existing methods unless otherwise specified.

[0033] Example 1

[0034] Step 1: Selection of seedbed and prevention of thrips in its surrounding environment:

[0035] 1) Selection of seedbed: The seedbed should be set up in an upwind area that is sheltered from the wind and facing the sun to ensure ventilation and air permeability on the seedbed.

[0036] 2) Clean the surrounding thrips living environment: remove or spray thrips host plants to reduce the source of thrips transmission; no thrips host plants should appear within 50 to 100 meters around the seedbed area. Thrips host plants include: Bidens pilosa, peppers, eggplants and various flowering plants. If thrips host plants appear within 50 to 100 meters around the seedbed, remove them 10 days before sowing tobacco;

[0037] For plants within 50 to 100 meters around the seedbed, 10 days before the tobacco seedlings emerge, chemical control is carried out against thrips. The pesticide used for chemical control is a ethyl spinetoram solution with a safe dosage for spraying. The safe dosage of each pesticide used in the following examples is prepared according to the instructions for use of each pesticide.

[0038] 3) Ground treatment of nursery ground: The seedling sheds are vertically set close to the ground and covered with black or silver-black plastic film with a width of more than one meter. This can improve the prevention and control effect of the environment in the seedling shed and reduce the pollution of foreign thrips.

[0039] Step 2: Planting and raising seedlings

[0040] 1) Use a 162-hole seedling tray with a size of 35 cm*65 cm to grow seedlings, and place two tobacco seeds in each hole when planting.

[0041] 2) After the seedlings are counted and planted, add 7-8 cm deep water to the nutrient solution pool in the seedling shed, apply 1000 g of tobacco floating seedling formula fertilizer to each shed, put 32 floating trays in each shed, set plastic film on the ground around the seedling shed for insulation, leave 10-15 cm at the bottom for ventilation, and set shade nets on the seedling shed for shade.

[0042] 3) In order to prevent pests from invading during the seedling stage, use insect-proof nets with a mesh size of 60 or more and set them at the opening of the seedling shed to achieve the effect of both seedling cultivation and insect prevention.

[0043] Step 3: Release of the sword-haired handkerchief mites

[0044] 1) When more than 90% of tobacco seedlings emerge after tobacco is planted (under natural conditions in Kunming, it takes about 10 days from planting to the emergence rate reaching more than 90%), thin out the seedlings by retaining one tobacco seedling in each hole.

[0045] 2) Inoculation of sword-haired handkerchief laelaps: On the second day after thinning, 4 to 12 sword-haired handkerchief laelaps were spread in the root soil of the plants on the floating seedling tray in each seedling hole. (The sword-haired handkerchief laelaps were raised by the method of Example 1 of CN202310743167.6 to obtain a material for 5,000 sword-haired handkerchief laelaps per bag, and one bag of sword-haired handkerchief laelaps can be spread on nearly 4 seedling floating trays).

[0046] 3) Monitor the occurrence of sword-haired handkerchief laelaps and thrips. Hang a blue board above each seedling bed to monitor the occurrence of thrips. Randomly sample the number of sword-haired handkerchief laelaps and thrips pupae in the seedling holes under three tobacco seedlings on each seedling bed.

[0047] The method provided in Example 1 was applied to floating nursery beds in Kunming to control tobacco seedling thrips, and three treatments were set up by scattering sword-haired handkerchief mites:

[0048] Treatment 1: 4 Laelaps scatted in each hole of the seedling tray;

[0049] Treatment 2: 8 Laelaps scatted in each hole of the seedling tray;

[0050] Treatment 3: 12 Laelaps mites were placed in each hole of the seedling tray;

[0051] Control group: no Laelaps spp. were released; each treatment was repeated 3 times.

[0052] When more than 90% of the tobacco seedlings have emerged and on the second day after thinning, the number of sword-haired handkerchief laelaps is scattered at the base of the tobacco seedlings of each treatment group. The number of sword-haired handkerchief laelaps and thrips is investigated on the 3rd, 5th, 7th, 10th, 15th, 20th, 30th and 40th days after the scattering of sword-haired handkerchief laelaps. The investigation is conducted until the tobacco seedlings grow to the point where they can be transplanted. The population of thrips and sword-haired handkerchief laelaps is monitored and investigated. The number of sword-haired handkerchief laelaps and thrips is obtained by statistics according to the existing method, and 5g of the seedling culture medium for each treatment is taken for statistics.

[0053] The survey results show that after releasing the sword-haired handkerchief laelaps according to the method provided in this application, the sword-haired handkerchief laelaps can colonize in the soil in the seedling tray and maintain the population density. The line graph of the survey results of the number of sword-haired handkerchief laelaps obtained in treatments 1 to 3 is shown in Figure 1 As shown. In treatment 1, the population can be maintained between 5 and 15; in treatment 2, the population can be maintained between 15 and 25; in treatment 3, the population can be maintained between 28 and 37. The number of sword-haired handkerchief mites in each treatment was higher than the release number, indicating that a population was formed.

[0054] The thrips pupae and other thrips stages in the soil in treatments 1 to 3 were counted and the results are shown in Table 1:

[0055] Table 1. The control effect of scattering sword-haired hand mites on thrips pupae in the soil

[0056]

[0057] Note: Pest reduction rate = 100*(initial pest density - late pest density) / initial pest density, control effect = 100*(treatment pest reduction rate - control pest reduction rate) / (100-control pest reduction rate);

[0058] The control effect of thrips pupae and other soil thrips insect stages in the soil was between 50% and 80%, with an average control effect of 66.81% (as shown in Table 1).

[0059] During the sampling survey, the number of thrips on the leaves and blue boards of tobacco seedlings in treatments 1 to 3 was investigated respectively. The results are shown in Tables 2 to 3:

[0060] Table 2. The control effect of scattering sword-haired hand mites on thrips on blue boards

[0061]

[0062]

[0063] Note: Pest reduction rate = 100*(initial pest density - late pest density) / initial pest density, control effect = 100*(treatment pest reduction rate - control pest reduction rate) / (100-control pest reduction rate)

[0064] Table 3. The control effect of scattering sword-haired handkerchief mites on thrips on tobacco leaves

[0065]

[0066] Note: Pest reduction rate = 100*(initial pest density - late pest density) / initial pest density, control effect = 100*(treatment pest reduction rate - control pest reduction rate) / (100 - control pest reduction rate)

[0067] As shown in Tables 2 and 3, the control effect of thrips monitored by the blue trapping board is between 30% and 60%, with an average control effect of 50.82% (Table 2), and the control effect of thrips investigated by leaves is between 30% and 80%, with an average control effect of 54.34% (Table 3). This shows that this method has a good control effect on thrips on tobacco in the seedling stage, and can effectively prevent the occurrence of various diseases and insect pests spread by thrips in the later stage of tobacco (thrips and the viruses they spread). After releasing the sword-haired handkerchief laelaps, this method has a good control effect on thrips on leaves and thrips on blue boards.

[0068] Example 2

[0069] The difference from Example 1 is that the host plants of thrips are eliminated by spraying a safe amount of imidacloprid solution.

[0070] Example 3

[0071] The difference from Example 1 is that the host plants of thrips are eliminated by spraying a safe amount of acetamiprid solution.

[0072] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for controlling thrips with sword-haired handkerchief mites during the tobacco floating tray seedling period, characterized in that: The following steps are involved: 1) Set up seedbeds in the upwind area that is leeward and sunny, and clear the host plants of thrips around the seedbeds; 2) After planting 2 tobacco seeds in each hole of the seedling tray, floating tray seedlings are raised, 32 floating trays are set in each seedling shed, the floating trays are set in a nutrient solution pool, tobacco floating seedling formula fertilizer is added to the nutrient solution pool, multiple seedling sheds are set close to form a seedling shed group, plastic films are vertically set around the seedling shed group, and insect-proof nets are set around the seedling shed group; 3) After the emergence rate of tobacco seedlings reaches more than 90%, thinning is carried out. On the second day after thinning, 4 to 12 sword-haired handkerchief mites are scattered in the root soil of the plants on the floating seedling tray at each seedling hole. Normal seedling management is carried out until the tobacco seedling transplanting period.

2. The method for controlling thrips with sword-haired handkerchief mites during the tobacco floating tray seedling raising period according to claim 1, characterized in that: Thinning should be done by retaining only one stronger plant in each hole.

3. The method for controlling thrips with sword-haired handkerchief mites in the tobacco floating tray seedling stage according to claim 1, characterized in that: The range of thrips host plant removal is at least 50m around the seedling shed group.

4. The method for controlling thrips with sword-haired handkerchief mites in the tobacco floating tray seedling stage according to claim 1, characterized in that: The plastic film "vertically set up plastic film around the seedling shed group" is a black or silver-black plastic film; the bottom of the plastic film is set close to the ground.

5. The method for controlling thrips with sword-haired handkerchief mites in the tobacco floating tray seedling stage according to claim 1, characterized in that: Thrips host plants include at least: Bidens pilosa, peppers, eggplants and various flowering plants.

6. The method for controlling thrips with sword-haired handkerchief mites in the tobacco floating tray seedling stage according to claim 1, characterized in that: Methods for removing thrips host plants include manual cleaning and spraying chemical pesticides.

7. The method for controlling thrips with sword-haired handkerchief mites in the tobacco floating tray seedling stage according to claim 6, characterized in that: The chemical pesticide reagent sprayed is at least one of spinetoram solution, imidacloprid solution and acetamiprid solution in a safe dosage.

8. The method for controlling thrips with sword-haired handkerchief mites in the tobacco floating tray seedling stage according to claim 1, characterized in that: The range of thrips host plant removal is within 50 to 100 meters around the seedling shed group.

9. The method for controlling thrips with sword-haired handkerchief mites in the tobacco floating tray seedling stage according to claim 1, characterized in that: The thrips host plant manipulation was carried out 10 days before tobacco sowing.

10. The method for controlling thrips with sword-haired handkerchief mites in the tobacco floating tray seedling stage according to claim 1, characterized in that: The preparation method of tobacco floating seedling formula fertilizer solution is as follows: first, add water into the nutrient solution pool, then add tobacco floating seedling formula fertilizer, and stir to dissolve.

Images