Field test research method for preventing and controlling prodenia litura by using noctuid black egg bees

Abstract

The invention relates to the technical field of prodenia litura prevention and control, in particular to a field test research method for prodenia litura prevention and control through noctuid black egg bees, which comprises the following steps: S1, planting a test field: planting 'K326' tobacco with the planting density of 1200 plants per 667 m < 2 > on yellow soil with the pH value of 5.5-7.4; according to the method, the control effect of the noctuid black-egg bees on the prodenia litura is tested by taking the noctuid black-egg bees as an object and adopting a field release test, the optimal field release technology of the optimal release distance, the release number and the release times of the noctuid black-egg bees is obtained, and the control on the field prodenia litura is improved by applying a combined control mode. Reference is provided for field green prevention and control of prodenia litura, and use of chemical pesticides is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of Spodoptera litura prevention and control, and in particular to a field test research method for preventing and controlling Spodoptera litura with black egg wasps. Background Art

[0002] The main damage caused by the Spodoptera litura larvae is that they have extremely strong host-searching abilities and can lay eggs on a variety of host plants. Female adults can reproduce more than 2,000 eggs in their lifetime. Under favorable conditions, the population can grow rapidly, causing serious damage to tobacco yield and quality.

[0003] At present, biological control mainly uses parasitic natural enemies, pathogenic microorganisms and predatory natural enemy insects. Parasitic natural enemies are important biological control resources for tobacco Noctuidae pests. Noctuidae black egg wasp belongs to the family of Hymenoptera. Noctuidae black egg wasp is an egg parasitoid of many important Lepidoptera pests. Noctuidae black egg wasp is highly affected by laboratory temperature and humidity, indicating that climatic conditions are crucial to the success of using Noctuidae black egg wasp to enhance biological control programs. The potential and value of Noctuidae black egg wasp as a biological control agent have been confirmed.

[0004] Beneficial bugs belong to the subfamily Beneficialinae of the family Pentatomidae in the order Hemiptera. Studies have shown that beneficiary bugs can prey on a variety of important agricultural pests, including the fall armyworm, fall armyworm, and diamondback moth.

[0005] Although the noctuid black egg wasp showed a high parasitism rate and control effect on Spodoptera litura in indoor studies, there are many natural factors in the field. Whether its effect on Spodoptera litura can remain the same as that in the indoor field remains to be studied. There are certain shortcomings in a single control method. For example, the noctuid black egg wasp is greatly affected by the weather. In such bad weather, its control effect may be poor. It is particularly important to combine with other natural enemies for control. Summary of the invention

[0006] The purpose of the present invention is to solve the problems in the background technology and to propose a field test research method for controlling Spodoptera litura with black egg wasps.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: The field test research method of the black egg wasp for controlling the cutworm includes the following steps: S1. Planting test field: On yellow soil with a pH of 5.5-7.4, the planting density of "K326" tobacco is 1200 plants / 667m2; S2. Feeding test insect sources: including the following species: a. The Spodoptera litura was reared and propagated in an artificial climate room with a temperature of 27±1℃, a relative humidity of 70%±5%, and a photoperiod of L:D=14h:10h, using 15cm high tobacco leaves. The adults were reared with 10% honey water. b. The fresh egg masses of Spodoptera litura were subcultured indoors and kept in an artificial climate chamber with a temperature of 25±1℃, RH70±5% and a photoperiod of 14L:10D. The adult Spodoptera litura black egg bees were then fed with 10% honey water after emergence. c. The beneficial bugs were raised in an artificial climate chamber at a temperature of 25±1°C, RH70±5%, and a photoperiod of 14L:10D, and the hatched larvae were then fed with armyworms; S3. Evaluate the control effect: a, releasing the noctuid black egg wasp at different distances, quantities, positions and times, determining the optimal field release amount, optimal diffusion distance and optimal release times of the noctuid black egg wasp, obtaining the optimal release technology of the noctuid black egg wasp in the field, and finally obtaining the control effect of the noctuid black egg wasp on the cutworm at different release distances, release quantities, release positions and release times; b. Release the black egg wasp of Spodoptera exigua and the beneficial bug together, that is, test 4 distances and 4 release combinations, obtain the insect population reduction rate and control effect, and finally obtain the effect of the black egg wasp of Spodoptera exigua and the beneficial bug in controlling the Spodoptera litura; S4. Perform data analysis: Excel 2010 was used for data statistics to calculate the insect population reduction rate and control effect of each treatment. SPSS 27.0 was then used for statistical analysis of the data. Finally, Tukey's HSD method was used for significance test (P<0.05).

[0008] Preferably, the fresh egg masses of the Spodoptera litura bee are collected through an egg-laying cloth, and after collection, the number of eggs on the egg-laying cloth is adjusted according to demand, and then placed in a 50 ml centrifuge tube, the tube mouth is sealed with a 150-mesh nylon gauze, and finally the gauze is opened when in use, and the hatched adult bees can fly out.

[0009] Compared with the existing technology, the field test research method for controlling Spodoptera litura by the black egg wasp provided by the present invention has the following advantages: The invention uses the black egg wasp of Spodoptera exigua as the object and adopts a field release experiment to test the control effect of the black egg wasp of Spodoptera exigua on Spodoptera litura, obtains the optimal field release technology of the optimal release distance, release quantity and release times of the black egg wasp of Spodoptera exigua, and applies a combined control method to improve the control of Spodoptera litura in the field, so as to provide a reference for the green control of Spodoptera litura in the field and reduce the use of chemical pesticides. DETAILED DESCRIPTION

[0010] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0011] Field test research methods for the control of Spodoptera litura by the black egg wasp include: S1. Planting test field: The test was conducted in the tobacco field of the Natural Enemy Insect Breeding Center in Jinhua Town, Fenggang County, Zunyi City, Guizhou Province, with an average altitude of 886 meters. The soil texture is yellow loam with a pH of 5.5-7.4. The tobacco variety planted in the test field is "K326", and then transplanting customization began. The planting density is 1,200 plants / 667m2. The tobacco grows well and the cultivation conditions are consistent. No chemical agents are applied during the test. Other operations are the same as the actual production of high-quality flue-cured tobacco; S2. Feeding test insect sources: including the following species: a. The Spodoptera litura was raised and propagated in an artificial climate room with a temperature of 27±1℃, a relative humidity of 70%±5%, and a light cycle of L:D=14h:10h using 15cm high tobacco, wherein the adults were raised with 10% honey water, and the fresh egg masses of the Spodoptera litura bee were collected through an egg-laying cloth, and after collection, the number of eggs on the egg-laying cloth was adjusted according to demand, and then placed in a 50ml centrifuge tube, the tube mouth was sealed with a 150-mesh nylon gauze, and finally the gauze was opened when in use, and the adult bees after eclosion could fly out; b. The fresh egg masses of Spodoptera litura were subcultured indoors and kept in an artificial climate chamber with a temperature of 25±1℃, RH70±5% and a photoperiod of 14L:10D. The adult Spodoptera litura black egg bees were then fed with 10% honey water after emergence. c. The beneficial bugs were raised in an artificial climate chamber at a temperature of 25±1°C, RH70±5%, and a photoperiod of 14L:10D, and the hatched larvae were then fed with armyworms; S3. Evaluate the control effect: a. The experiment set up three release densities (100, 200, 300), seven release distances (0m, 5m, 10m, 15m, 20m, 25m and 30m) and three egg hanging heights (upper, middle and lower). The control was not treated. Each plot was 60m2 and covered with gauze. Each treatment was repeated 6 times, with a total of 18 plots, and the plots were randomly distributed. The egg cloth with the black egg wasp that was about to emerge was placed in the bee tube, and different densities of parasitized egg masses were placed in each. At 0m, 5m, 10m, 15m, 20m, 25m and 30m away from the bee tube, the egg cards with hosts (egg age is the best parasitized egg age of Spodoptera exigua) were randomly hung on the back of tobacco leaves (upper, middle and lower parts) to induce Spodoptera exigua to lay eggs. Two days later, the hanging egg cards were retrieved and brought back to the artificial climate box for cultivation and observation, and the parasitism of host egg masses was recorded, and the insect population reduction rate and control effect were calculated. Based on the field data results of different release amounts and release distances, the optimal field release amount and optimal diffusion distance of Spodoptera exigua were obtained; b. The experiment set up three release times: ① Release only once: release the best release amount of Noctuidae black egg wasp once on the first day; ② Release twice: release the best release amount of Noctuidae black egg wasp twice, with an interval of 1d between each release; ③ Release three times: release the best release amount of Noctuidae black egg wasp three times in a row, once a day. ④ The control was not treated. Each plot has an area of ​​60m2 and is covered with gauze. Each treatment was repeated 6 times, for a total of 18 plots, which were randomly distributed. Put the bee tube with the best release amount into the field, hang a host egg card on the back of the tobacco leaf at the best release distance to lure Noctuidae black egg wasp to lay eggs, retrieve the egg mass on the second day and take it back to the artificial climate chamber for cultivation and observation, and hang a new egg card at the same position at the same time. The operation was continued for three days, and the number of parasitized egg masses was observed and recorded every day to obtain the best release number (200 bees), thereby obtaining the best release technology of Noctuidae black egg wasp in the field; c. The experiment set up 4 distances (0m, 5m, 10m and 15m) and 4 release combinations (Spodoptera exigua + beneficial bugs, Spodoptera exigua, beneficial bugs and control treatments) (see Table 1): Table 1 Experimental treatment design All plots were covered with gauze, and each treatment was repeated 4 times. Treatment ①: Only the black egg wasp of the noctuid wasp was released, and the release was carried out according to the optimal release amount (200 bees) obtained in a. Treatment ②: Only the beneficial stink bug (3 instar) was released, and the benefit-harm ratio was 1:10. Treatment ③: Release the black egg wasp of the noctuid wasp + the beneficial stink bug, first release the black egg mass of the noctuid wasp, and then release the beneficial stink bug 4 days later. Treatment ④: Control treatment, no treatment. Hang an egg card at a distance in all plots, and then release different combinations of natural enemies. After 7 days of the experiment, the number of Spodoptera litura on the tobacco plants was investigated and counted, and the insect population reduction rate and prevention effect were calculated.

[0012] S4. Perform data analysis: Excel 2010 was used for data statistics, and the insect population reduction rate and control effect of each treatment were calculated using the following formula.

[0013] SPSS27.0 was then used to perform statistical analysis on the data, and Tukey's HSD method was used for significance testing (P<0.05), and the following results were obtained: 1. The control effect of the black egg wasp on the Spodoptera litura wasp was significantly affected by different release distances, release quantities and release sites (Table 2 and Table 3): Table 2 The control effect of Spodoptera exigua at different positions and distances against Spodoptera litura

[0014] Table 3 The control effect of different densities of Spodoptera exigua on Spodoptera litura

[0015] At the same release bee density, when the release distance is ≤15m, the control effect of the black egg wasp on the Spodoptera litura in three different positions is significantly higher than that at 20m, 25m and 30m, and there are significant differences in the control effect between the upper, middle and lower positions. At the same release bee density, the control effect of the black egg wasp of the Spodoptera litura will show a downward trend with the increase of time and distance; when the release distance is ≤20m, the control effect of the upper and middle positions is significantly higher than that of the lower part, and the best control effect is on the third day, which is significantly different from the fifth and seventh days. Among them, at the three release densities, the control effect at a distance of 10m reached the highest, which was 41.36±3.35%, 45.14±8.8% and 55.17±7.28% respectively.

[0016] 2. At the same release distance and release position, when the release distance is ≤20m, the control effect of releasing 200 and 300 black egg wasps on Spodoptera litura was significantly higher than that of releasing 100. The control effect of 200 and 300 wasps reached the highest at 10m, which was 45.14±8.8% and 55.17±7.28%, and there was no significant difference between the two (Table 4).

[0017] Table 4 The control effect of different release times of black eggs of Spodoptera litura on Spodoptera litura Note: The numbers in the table are mean values ​​± annotation errors. Capital letters A, B, and C indicate significant differences among different release times (P<0.05). Lowercase letters a, b, c, and d indicate significant differences among different release distances (P<0.05).

[0018] 3. The effect of the joint prevention and control of Spodoptera litura with Noctuidae black egg wasp and beneficial bugs. There are significant differences in the control effect of Noctuidae black egg wasp on Spodoptera litura at different release distances and release methods (Table 5). Under a single release method, there are significant differences in the control effect of beneficial bugs and Noctuidae black egg wasp at different release distances, reaching the maximum at 0m, which is 57.53±1.26%; and when the release distance is ≤10m, the control effect is significantly higher than that at 15m. Under joint prevention and control, the control effect varies significantly between different distances. The control effect decreases with the increase of distance, and the control effect is best at 0m (70.69±2.64%). At the same release distance, the effect of joint prevention and control is significantly different from that of single prevention and control (beneficial bugs or Noctuidae black egg wasp): Table 5 The control effect of the combination of Spodoptera exigua and beneficial bugs on Spodoptera litura Note: The numbers in the table are mean values ​​± annotation errors. Capital letters A, B, and C indicate significant differences between different release distances (P<0.05). Lowercase letters a, b, c, and d indicate significant differences between different release methods (P<0.05). “-” indicates no protective effect.

[0019] Therefore, in this study, the black egg wasp of Spodoptera exigua showed a good parasitic effect on Spodoptera litura in the field. Compared with previous studies, this study investigated the control effect of different release distances, release numbers and release times of the black egg wasp of Spodoptera exigua on Spodoptera litura, as well as the control effect of the combined beneficial bugs on Spodoptera litura; At the same time, in this study, the release density of the noctuid black egg wasp against the cutworm was explored. By analyzing the insect population reduction rate and control effect after the release of natural enemies, the optimal release technology for field control of cutworm was obtained, which laid an important foundation for the field application and promotion of the noctuid black egg wasp. In addition, the overall control effect of the noctuid black egg wasp on the cutworm showed a downward trend with the increase of time and distance. In order to obtain better control effects, exploring the combined use of natural enemies will be an important research direction; similarly, the use of pesticides and natural enemies for joint control is also an important research direction, and the safety of pesticides on natural enemies is also worthy of attention. At present, some scholars have begun to pay attention to the above issues, and evaluated the safety of 8 common control pesticides for fall armyworm on the noctuid black egg wasp, and evaluated the safety of insecticides on the yellow-eyed trichogrammatid. At present, the field application of the noctuid black egg wasp is relatively small, and the combined application with other natural enemies of the noctuidae family is even rarer. In addition, in this study, the control effects of different release distances, release numbers, and release times all showed a trend of first increasing and then decreasing. The reason for this phenomenon may be due to the influence of outdoor temperature deviation, which led to a decrease in the survival rate of Spodoptera exigua in high temperature outdoor environments, and ultimately led to poor control effects in the later stages. Therefore, in order to improve the survival rate of Spodoptera exigua, in this study, the natural enemies took climate factors into full consideration when releasing them, and chose to release Spodoptera exigua in clear, windless weather.

[0020] In summary, in this study, the optimal release technology of Spodoptera litura in the field was explored. The results showed that a set of optimal release technology for Spodoptera litura wasps was obtained. The specific release technology is as follows: the parasitized host eggs are packed in 200 pieces / tube, the tube mouth is sealed with gauze, and a centrifuge tube is placed every 10-15m, and the placement position can be in the middle and upper part of the tobacco plant. Since it is difficult to observe adults in the field, a result trap is needed to determine the period when adults of Spodoptera litura appear in the field. When adults are observed by trapping, the Spodoptera litura wasps can be released. If young larvae are still observed in the field, release them continuously for 2 to 3 times. At the same time, pay attention to the weather conditions when releasing. Do not release on rainy days or high temperatures. It is recommended to release in the early morning or evening.

[0021] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A field trial research method for controlling Spodoptera litura with the black egg wasp, characterized in that: The following steps are involved: S1. Planting test field: On yellow soil with a pH of 5.5-7.4, the planting density of "K326" tobacco is 1200 plants / 667m2; S2. Feeding test insect sources: including the following species: a. The Spodoptera litura was reared and propagated in an artificial climate room with a temperature of 27±1℃, a relative humidity of 70%±5%, and a photoperiod of L:D=14h:10h, using 15cm high tobacco leaves. The adults were reared with 10% honey water. b. The fresh egg masses of Spodoptera litura were subcultured indoors and kept in an artificial climate chamber with a temperature of 25±1℃, RH70±5% and a photoperiod of 14L:10D. The adult Spodoptera litura black egg bees were then fed with 10% honey water after emergence. c. The beneficial bugs were raised in an artificial climate chamber at a temperature of 25±1°C, RH70±5%, and a photoperiod of 14L:10D, and the hatched larvae were then fed with armyworms; S3. Evaluate the control effect: a, releasing the noctuid black egg wasp at different distances, quantities, positions and times, determining the optimal field release amount, optimal diffusion distance and optimal release times of the noctuid black egg wasp, obtaining the optimal release technology of the noctuid black egg wasp in the field, and finally obtaining the control effect of the noctuid black egg wasp on the cutworm at different release distances, release quantities, release positions and release times; b. Release the black egg wasp of Spodoptera exigua and the beneficial bug together, that is, test 4 distances and 4 release combinations, obtain the insect population reduction rate and control effect, and finally obtain the effect of the black egg wasp of Spodoptera exigua and the beneficial bug in controlling the Spodoptera litura; S4. Perform data analysis: Excel 2010 was used for data statistics to calculate the insect population reduction rate and control effect of each treatment. SPSS 27.0 was then used for statistical analysis of the data. Finally, Tukey's HSD method was used for significance test (P<0.05).

2. The field test research method for controlling Spodoptera litura by the black egg wasp of Noctuidae according to claim 1, characterized in that: The fresh egg masses of the Spodoptera litura bee are collected through an egg-laying cloth, and after being collected, the number of eggs on the egg-laying cloth is adjusted according to demand, and then put into a 50ml centrifuge tube, the tube mouth is sealed with a 150-mesh nylon gauze, and finally the gauze is opened when in use, and the adult bees after molting can fly out.

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