Indoor evaluation method for benefit-harm ratio of miridae and plant hopper

Abstract

The invention discloses an indoor evaluation method for the benefit-harm ratio of miridae to plant hopper, and relates to the technical field of rice disease and insect pest prevention and control. The specific evaluation method comprises the following steps: planting test rice; a test group, a control group and a blank group are designed, each group is provided with 3-4 repetitions, and the test groups are obtained by respectively inoculating miridae and brood planthopper female adults with different benefit-harm ratios into the test groups; the control group is only inoculated with brood plant hopper female adults with the same number as that of the test groups; the blank group is a female adult without grafting any miridae and brood planthopper; when more than 90% of rice seedlings in the control group wither, starting to record the seedling death rate, and determining the evaluation level and the pest control effect; and when the pest control effect is medium or high, the benefit-pest ratio can effectively control the development of the plant hoppers in a short time. According to the method, the prevention and control effect of the benefit-harm ratio of the miridae and the plant hopper on the plant hopper can be evaluated indoors, and the method is easy to operate, short in time consumption and high in accuracy.

Description

Technical Field

[0001] The invention relates to the technical field of rice pest control, and in particular to an indoor evaluation method for the benefit-harm ratio of blind bugs and plant hoppers. Background Art

[0002] Rice planthoppers are insects of the family Delphacidae in the order Homoptera and are one of the main pests of rice. Rice planthoppers harm rice by sucking plant sap, which can cause yellow leaves or leaf death, resulting in reduced rice production or even no harvest. Common species of rice planthoppers include brown planthoppers, white-backed planthoppers and gray planthoppers. Black-shouldered green stink bugs and Chinese pale-winged stink bugs are important predatory natural enemies of rice planthoppers. They like to eat planthopper eggs and young larvae. On average, each stink bug can suck more than 200 planthopper eggs in its lifetime. Therefore, they play an important role in green control of rice fields. In green control in the field, the benefit-harm ratio of natural enemies to pests is a hot topic of research. If too few natural enemies are released, pests cannot be effectively controlled, and if too many natural enemies are released, the breeding costs will be wasted. Therefore, it is particularly important to evaluate the benefit-harm ratio of natural enemies to pests. At present, the evaluation of the benefit-harm ratio of natural enemies is mainly done by releasing them in the field and recording the population dynamics of natural enemies and pests. However, this evaluation method is easily affected by the environmental climate, takes a long time, and the crop yield in the field control area may be affected, which is not easy to operate. Therefore, developing an indoor method that can be operated to evaluate the benefit-harm ratio of blind bugs and planthoppers for the continuous control of planthoppers will play an important role in future green control. Summary of the invention

[0003] In view of the above shortcomings, the present invention provides an indoor evaluation method for the benefit-harm ratio of blind bugs and rice planthoppers, which solves the problem that the benefit-harm ratio of blind bugs and rice planthoppers can only be evaluated through field release, and realizes rapid and accurate evaluation indoors. The specific technical scheme is as follows:

[0004] An indoor evaluation method for the benefit-harm ratio of blind bugs and plant hoppers comprises the following steps:

[0005] (1) Experimental rice planting: After soaking and germinating the rice seeds, the rice seeds were sown in plastic cups. When the rice seedlings grew to 10-12 cm, the poorly developed rice seedlings were removed and the strong seedlings were retained;

[0006] (2) Experimental design:

[0007] S1. Design 3-4 experimental groups, a control group and a blank group, with 3-4 replicates in each group;

[0008] The test groups are: blind bugs and female adults of egg-bearing plant hoppers with different benefit-harm ratios are introduced into each test group;

[0009] The control group is: only the same number of female adults of egg-bearing plant lice as that of the test group are inoculated;

[0010] The blank group was: no female adults of blind bugs and egg-bearing plant hoppers were inoculated;

[0011] The number of rice seedlings in the test group, the control group and the blank group is the same, and the ratio of the number of female adults of egg-bearing planthoppers to the number of rice seedlings in the test group is 1:1-3;

[0012] S2. When more than 90% of the rice seedlings in the cups of the control group have withered, start recording the seedling death rate of each repetition, determine the evaluation level according to the seedling death rate, calculate the mean of the evaluation level of each group, and determine the pest control effect according to the mean of the evaluation level; when the pest control effect is medium or high, it proves that the benefit-harm ratio of the blind bug to the planthopper can effectively control the development of the planthopper in a short time.

[0013] Preferably, in step (1), the diameter of the plastic cup is 10-14 cm and the height is 15-20 cm.

[0014] Preferably, in step (1), the sowing is performed by sowing 35-45 seeds per cup; and the number of the strong seedlings retained is 25-40 plants.

[0015] Preferably, in step (2), the benefit-harm ratio is the ratio of the number of blind bugs to the number of female adults of egg-bearing planthoppers; the benefit-harm ratio is 1:1-20.

[0016] Preferably, in step (2), the evaluation level is: when the seedling death rate is 0, the evaluation level is 0; when the seedling death rate is below 10.0%, the evaluation level is 1; when the seedling death rate is 11%-25%, the evaluation level is 3; when the seedling death rate is 26%-50%, the evaluation level is 5; when the seedling death rate is 51%-90%, the evaluation level is 7; when the seedling death rate is greater than 90%, the evaluation level is 9.

[0017] Preferably, in step (2), the pest control effect is: when the evaluation level is 0-3, the pest control effect is high; when the evaluation level is 4-6, the pest control effect is medium; when the evaluation level is 7-9, the pest control effect is low.

[0018] Preferably, the blind bug is Lygus sinensis or Lygus nigromaculata; the planthopper is Nilaparvata lugens or Sogatella furcifera.

[0019] Preferably, the temperature during the entire evaluation process is controlled at 22-25° C., the humidity is 70-80%, and the photoperiod L:D is 14:10.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention scientifically and reasonably designs indoor tests, divides the evaluation levels according to the seedling mortality rate, and divides the pest control effects according to the evaluation levels, so as to realize the evaluation of the control effect of blind bugs and planthoppers on rice planthoppers indoors, and solves the problems that the outdoor field evaluation method is greatly affected by the environment, is time-consuming, and is inconvenient to operate. The test shows that when the test rice variety is the insect-susceptible variety TN1, a benefit-harm ratio of 1:2 can achieve a high level of pest control; when the test rice variety is the medium-resistant brown planthopper variety Guiyu No. 11, a benefit-harm ratio of 1:8 can achieve a high level of pest control, and a benefit-harm ratio of 1:12 can achieve a medium level of pest control.

[0022] 2. The test method of the present invention is simple, easy to operate, and short in time. The results are used for field prevention and control, and the prevention and control effect is basically consistent with the indoor test results with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for describing the embodiments are briefly introduced below.

[0024] Figure 1 The death of rice seedlings at different benefit-harm ratios in Example 1 of the present invention.

[0025] Figure 2 The death of rice seedlings at different benefit-harm ratios in Example 2 of the present invention. DETAILED DESCRIPTION

[0026] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0027] Example 1

[0028] (1) Experimental rice planting: After soaking and germination, rice variety TN1 (a well-known insect-susceptible variety, Taichung Native 1) was sown in plastic cups (14 cm in diameter and 20 cm in height), with 40 seeds sown in each cup. After 7 days, when the rice seedlings grew to 10-12 cm, the poorly developed rice seedlings were removed and 30 strong seedlings were left in each row of the cups.

[0029] (2) Experimental design: Design three experimental groups, a control group, and a blank group;

[0030] Experimental group 1: 10 Chinese pale-winged stink bugs (5 males and 5 females) and 10 female brown planthoppers bearing eggs were inoculated into the plastic cups planted with 30 TN1 rice seedlings, with a benefit-harm ratio of 1:1;

[0031] Experimental group 2: 5 Chinese pale-winged stink bugs (3 females and 2 males) and 10 female brown planthoppers bearing eggs were inoculated into the plastic cups planted with 30 TN1 rice seedlings, with a benefit-harm ratio of 1:2;

[0032] Experimental group 3: Two Chinese pale-winged stink bugs (one male and one female) and ten female brown planthoppers bearing eggs were placed in the plastic cups planted with 30 TN1 rice seedlings, with a benefit-harm ratio of 1:5;

[0033] Control group: only 10 female brown planthoppers bearing eggs were inoculated into the plastic cups planted with 30 TN1 rice seedlings;

[0034] Blank group: No blind bugs or female adults of egg-bearing planthoppers were inoculated into the plastic cups planted with 30 TN1 rice seedlings.

[0035] The plants were covered with nylon nets, and four replicates were set for each treatment. Watering was carried out every day. The temperature was controlled at 25°C, the humidity was 70%, and the photoperiod L:D was 14:10 during the entire evaluation process.

[0036] Evaluation method: When more than 90% of the rice seedlings in the cups of the control group withered, start recording the seedling death rate of each repetition, and determine the evaluation level according to the seedling death rate (see Table 1), calculate the mean of the evaluation level of each group, and determine the pest control effect according to the mean of the evaluation level (see Table 2); when the pest control effect is medium or high, it proves that the benefit-harm ratio of the blind bug to the planthopper can effectively control the development of the planthopper in a short time, and the results are shown in Table 3.

[0037] Table 1 Evaluation criteria for the control of planthoppers by blind bugs

[0038] Evaluation level Seedling mortality rate 0 0 1 10.0% or less 3 11％-25％ 5 26％-50％ 7 51％-90％ 9 >90.1

[0039] Table 2 Evaluation of the control effect of blind bugs on planthoppers

[0040] Evaluation level range Pest control effect 0-3 high 4-6 middle 7-9 Low

[0041] Table 3 Evaluation of the pest control effect of different benefit-harm ratios of Lygus sinensis and N. lugens on rice variety TN1

[0042]

[0043] Table 3 shows that the treatments with a benefit-harm ratio of 1:1 and 1:2 had a high level of pest control effect, so it is believed that this benefit-harm ratio can effectively control the development of planthoppers in a short period of time.

[0044] Example 2

[0045] (1) Experimental rice planting: After soaking and germination of rice varieties Guiyu No. 11 (a conventional rice variety known to be moderately resistant to brown planthoppers), seeds were sown in plastic cups (12 cm in diameter and 15 cm in height), with 45 seeds sown in each cup. After 10 days, when the rice seedlings grew to 10-12 cm, the poorly developed rice seedlings were removed, leaving 24 strong seedlings in each row in the cup.

[0046] (2) Experimental design: Design three experimental groups, a control group, and a blank group;

[0047] Experimental group 1: 3 Chinese pale-winged stink bugs (2 females and 1 male) and 24 female brown planthoppers bearing eggs were inoculated into the plastic cups planted with 24 Guiyu No. 11 rice seedlings, with a benefit-harm ratio of 1:8;

[0048] Experimental group 2: Two Chinese pale-winged stink bugs (one male and one female) and 24 female brown planthoppers bearing eggs were placed in the plastic cups planted with 24 Guiyu No. 11 rice seedlings, with a benefit-harm ratio of 1:12;

[0049] Control group: only 24 female brown planthoppers bearing eggs were placed in the plastic cups planted with 24 Guiyu No. 11 rice seedlings;

[0050] Blank group: No blind bugs or female adults of egg-bearing planthoppers were placed in the plastic cups planted with 24 Guiyu No. 11 rice seedlings.

[0051] Since Guiyu No. 11 is a conventional rice variety with moderate resistance to brown planthoppers, the benefit-harm ratio was increased to 1:8 and 1:12 for testing.

[0052] The plants were covered with nylon nets, and four replicates were set for each treatment. Watering was carried out every day. The temperature was controlled at 25°C, the humidity was 70%, and the photoperiod L:D was 14:10 during the entire evaluation process.

[0053] Evaluation method: When more than 90% of the rice seedlings in the cups of the control group withered, the seedling death rate of each repetition was recorded, and the evaluation level was determined according to the seedling death rate (see Table 1), the mean of the evaluation level of each group was counted, and the pest control effect was determined according to the mean of the evaluation level (see Table 2); when the pest control effect was medium or high, it was proved that the benefit-harm ratio of the blind bug to the planthopper could effectively control the development of the planthopper in a short time. The results are shown in Table 4:

[0054] Table 4 Evaluation of the pest control effect of different benefit-harm ratios of Chinese pale-winged stink bug and brown planthopper on rice variety Guiyu 11

[0055]

[0056] Table 4 shows that when the benefit-harm ratio is 1:8, the pest control effect on the rice variety Guiyu No. 11 is at a high level, and when the benefit-harm ratio is 1:12, the pest control effect is at a medium level.

[0057] Field validation test:

[0058] The applicant conducted a field verification test at the Guangxi Academy of Agricultural Sciences Rice Planting Experimental Base (in Nanning City). The experimental fields were four isolated rice fields. The rice was transplanted rice seedlings for about 10 days. The occurrence of planthoppers was similar, with adults being the main cause of damage. The area of ​​the first three fields was about 0.3hm2 , the fourth field area is 0.1hm 2 No pesticides were sprayed on the experimental fields during the experiment, and conventional rice cultivation management was followed. The number of rice planthoppers and blind bugs in the field was investigated using the pot-patting method. Parallel jump sampling was used at 10 points for each treatment, and two rice clumps were investigated at each point. The number of brown planthoppers in the field was investigated on the 1st, 7th and 14th days. Chinese pale-winged blind bugs were released according to the number of planthoppers investigated on the 1st day.

[0059] Experimental plot 1 was Guiyu No. 11, which was inoculated with Chinese pale-winged blind bug at a benefit-harm ratio of 1:8. Experimental plot 2 was Guiyu No. 11, which was inoculated with Chinese pale-winged blind bug at a benefit-harm ratio of 1:12. Experimental plot 3 was TN1 rice, which was inoculated with Chinese pale-winged blind bug at a benefit-harm ratio of 1:5. Experimental plot 4 was the TN1 rice control group, which was not inoculated with Chinese pale-winged blind bug. The results are shown in Table 5.

[0060] Table 5 Field test on the control effect of brown planthopper at different benefit-harm ratios

[0061]

[0062] In the table, capital letters indicate significant differences in the number of brown planthoppers among the four fields; lowercase letters indicate significant differences in the number of brown planthoppers among the other three fields except field 4.

[0063] The results in Table 5 show that releasing Chinese pale-winged stink bugs with different ratios of benefit-harm ratio at the beginning of the migration of brown planthopper adults and the beginning of egg-laying can significantly reduce the number of newly hatched nymphs of brown planthoppers on the 7th day and the number of older nymphs on the 14th day compared with the control plot 4. Especially on Guiyu No. 11 rice, when releasing Chinese pale-winged stink bugs with a benefit-harm ratio of 1:8, the control effect was significant, and the insect population density could be significantly reduced on the 7th day, which is basically consistent with the results of the indoor experiment.

[0064] In summary, the present invention can evaluate the control effect of blind bugs and planthoppers on rice planthoppers by scientifically and reasonably designing indoor tests, dividing the evaluation levels according to the seedling death rate, and dividing the pest control effect according to the evaluation levels, thereby solving the problems of outdoor field evaluation methods being greatly affected by the environment, time-consuming, and inconvenient to operate. The test shows that when the test rice variety is the insect-susceptible variety TN1, a benefit-harm ratio of 1:2 can achieve a high level of pest control; when the test rice variety is the medium-resistant brown planthopper variety Guiyu No. 11, a benefit-harm ratio of 1:8 can achieve a high level of pest control, and a benefit-harm ratio of 1:12 can achieve a medium level of pest control. The test method of the present invention is simple, easy to operate, and time-consuming. The results are used for field control, and the control effect is basically consistent with the indoor test results, with high accuracy.

[0065] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. An indoor evaluation method for the benefit-harm ratio of blind bugs and planthoppers, characterized in that: The following steps are involved: (1) Experimental rice planting: After soaking and germinating the rice seeds, the rice seeds were sown in plastic cups. When the rice seedlings grew to 10-12 cm, the poorly developed rice seedlings were removed and the strong seedlings were retained; (2) Experimental design: S1. Design 3-4 experimental groups, a control group and a blank group, with 3-4 replicates in each group; The test groups are: blind bugs and female adults of egg-bearing plant hoppers with different benefit-harm ratios are introduced into each test group; The control group is: only the same number of female adults of egg-bearing plant lice as that of the test group are inoculated; The blank group was: no female adults of blind bugs and egg-bearing plant hoppers were inoculated; The number of rice seedlings in the test group, the control group and the blank group is the same, and the ratio of the number of female adults of egg-bearing planthoppers to the number of rice seedlings in the test group is 1:1-3; S2. When more than 90% of the rice seedlings in the cups of the control group have withered, start recording the seedling death rate of each repetition, determine the evaluation level according to the seedling death rate, calculate the mean of the evaluation level of each group, and determine the pest control effect according to the mean of the evaluation level; when the pest control effect is medium or high, it proves that the benefit-harm ratio of the blind bug to the planthopper can effectively control the development of the planthopper in a short time.

2. The indoor evaluation method for the benefit-harm ratio of blind bugs and planthoppers according to claim 1, characterized in that: In step (1), the diameter of the plastic cup is 10-14 cm and the height is 15-20 cm.

3. The indoor evaluation method for the benefit-harm ratio of blind bugs and planthoppers according to claim 1, characterized in that: In step (1), the sowing is performed by sowing 35-45 seeds per cup; and the number of the strong seedlings retained is 25-40 plants.

4. The indoor evaluation method for the benefit-harm ratio of blind bugs and planthoppers according to claim 1, characterized in that: In step (2), the benefit-harm ratio is the ratio of the number of blind bugs to the female adults of egg-bearing planthoppers; the benefit-harm ratio is 1:1-20.

5. The indoor evaluation method for the benefit-harm ratio of blind bugs and planthoppers according to claim 1, characterized in that: In step (2), the evaluation levels are: when the seedling death rate is 0, the evaluation level is 0; when the seedling death rate is less than 10.0%, the evaluation level is 1; when the seedling death rate is 11%-25%, the evaluation level is 3; when the seedling death rate is 26%-50%, the evaluation level is 5; when the seedling death rate is 51%-90%, the evaluation level is 7; when the seedling death rate is greater than 90%, the evaluation level is 9.

6. The indoor evaluation method for the benefit-harm ratio of blind bugs and planthoppers according to claim 1, characterized in that: In step (2), the pest control effect is: when the evaluation level is 0-3, the pest control effect is high; when the evaluation level is 4-6, the pest control effect is medium; when the evaluation level is 7-9, the pest control effect is low.

7. The indoor evaluation method for the benefit-harm ratio of blind bugs and planthoppers according to claim 1, characterized in that: The blind bug is Lygus sinensis or Lygus nigromaculata; the planthopper is Nilaparvata lugens or Sogatella furcifera.

8. The indoor evaluation method for the benefit-harm ratio of blind bugs and planthoppers according to claim 1, characterized in that: The temperature during the entire evaluation process was controlled at 22-25°C, the humidity was 70-80%, and the photoperiod L:D was 14:10.

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