Method for synergistically preventing and treating spodoptera frugiperda by using cantheconidea furcellata and high-efficiency and low-toxicity insecticide

Abstract

The invention relates to the field of crop disease and pest control, in particular to a method for synergistically controlling spodoptera frugiperda by using cantheconidea furcellata and a high-efficiency and low-toxicity insecticide. According to the method, in the corn seedling stage and the small horn mouth stage, when the number of spodoptera litura on hundreds of crops is larger than or equal to 30, cantheconidea furcellata adults are released for prevention and control; and spraying a high-efficiency low-toxicity insecticide after 25-32 days of prevention and treatment. According to the invention, by integrating the cantheconidea furcellata and the insecticide which has no direct lethal effect and no obvious sub-lethal effect on the cantheconidea furcellata, the purposes of continuously preventing and controlling the grassland spodoptera litura and reducing the use amount and the use frequency of the pesticide can be achieved.

Description

Technical Field

[0001] The present invention relates to the field of crop pest control, and particularly to a method for synergistically controlling Spodoptera frugiperda using Eocanthecona furcellata and highly effective and low-toxic pesticides. Background Art

[0002] Spodoptera frugiperda belongs to the Noctuidae family of Lepidoptera and is a major migratory pest worldwide. Spodoptera frugiperda has a wide host range and can feed on 353 plant species in 76 families, but mainly feeds on and damages maize.

[0003] Applying chemical pesticides is the main means of controlling Spodoptera frugiperda. Screening highly effective and low-toxic pesticides is an important part of scientifically controlling Spodoptera frugiperda. However, the use of pesticides may kill pest natural enemies and weaken the control effect of natural enemies on Spodoptera frugiperda. In addition, Spodoptera frugiperda has developed varying levels of resistance to commonly used pesticides, increasing the difficulty of control, resulting in an increase in the amount of pesticides used, raising the control cost, and increasing the environmental burden.

[0004] Eocanthecona furcellata is an important predatory natural enemy of Spodoptera frugiperda. Different instars of Eocanthecona furcellata can prey on Spodoptera frugiperda larvae. Adult male and female Eocanthecona furcellata have a good control effect on the older larvae of Spodoptera frugiperda, and the maximum daily predation amounts on the 3rd, 4th, and 5th instar larvae of Spodoptera frugiperda can reach 59, 49, and 14 respectively. In addition, Eocanthecona furcellata has a preference for the 6th instar larvae and prepupae of Spodoptera frugiperda. The control effect of Eocanthecona furcellata on Spodoptera frugiperda can form a good complementary effect with the high control efficacy of pesticides on the younger larvae. However, when testing the control efficacy of pesticides on Spodoptera frugiperda, we often ignore their impact on the important natural enemies of Spodoptera frugiperda. The acute lethal and sublethal effects of pesticides on non-target natural enemy insects usually weaken the control effect of natural enemies on pests, and instead may cause the resurgence of pests, especially migratory pests. Summary of the Invention

[0005] The purpose of the present invention is to provide a comprehensive application of Eocanthecona furcellata and pesticides to improve the control efficiency of Spodoptera frugiperda.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] The present invention provides a method for synergistically controlling Spodoptera frugiperda using Eocanthecona furcellata and highly effective and low-toxic pesticides, including the following steps:

[0008] During the maize seedling stage and the small trumpet stage, when the number of Spodoptera frugiperda insects per 100 plants ≥ 30, release adult Eocanthecona furcellata for control; after 25 - 32 days of control, spray highly effective and low-toxic pesticides.

[0009] Preferably, the density of the adult Eocanthecona furcellata is 30 - 50 individuals per mu.

[0010] Preferably, the male - female ratio of the adult Eocanthecona furcellata is 1:1.

[0011] Preferably, the types of the highly - effective and low - toxicity insecticides are one or more of emamectin benzoate, chlorfenapyr, chlorantraniliprole, and tetramide.

[0012] Preferably, the spraying concentration of the highly - effective and low - toxicity insecticide is 2.50 - 55.00 ppm.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] The present invention combines the natural enemy Eocanthecona furcellata and insecticides, protects and utilizes the control effect of Eocanthecona furcellata on Spodoptera frugiperda, accurately uses highly - effective insecticides, reduces the usage times and amounts of pesticides, improves the prevention and control effect, is conducive to delaying the drug resistance of pesticides, reducing pesticide residues, and helps to improve food safety. Detailed Embodiments

[0015] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0016] Embodiment 1

[0017] 1. Tested Insecticides

[0018] Nine common insecticides used for controlling Spodoptera frugiperda were selected. Information such as the name, manufacturer, active ingredient content, and dosage form of the insecticides is shown in Table 1.

[0019] Table 1 Tested Insecticides

[0020]

[0021]

[0022] 2. Field Control Effect of Insecticides on Spodoptera frugiperda

[0023] The field control effects of 9 insecticides against Spodoptera frugiperda are shown in Table 2 and Table 3. One day after treatment, there were significant differences in the corrected control effects of the 9 insecticides against Spodoptera frugiperda (F = 7.33, df = 8, 18, P < 0.001). Among them, the corrected control effects of chlorantraniliprole, emamectin benzoate, spinetoram and chlorfenapyr were significantly higher than that of lufenuron. Three days after treatment, there were also significant differences in the corrected control effects of the 9 insecticides against Spodoptera frugiperda (F = 7.90, df = 8, 18, P < 0.001). Among them, the corrected control effects of lufenuron and tetraniliprole were significantly lower than those of other insecticides except cyantraniliprole. Seven days after treatment, there were also significant differences in the corrected control effects of the 9 insecticides against Spodoptera frugiperda (F = 11.78, df = 8, 18, P < 0.001). Except that the average corrected control effects of lufenuron, cyantraniliprole, tetraniliprole and broflanilide were between 82.2% and 87.8%, the average corrected control effects of the remaining insecticides were all greater than 91%, and the corrected control effects of chlorantraniliprole, indoxacarb and spinetoram were significantly higher than those of lufenuron, cyantraniliprole and tetraniliprole.

[0024] Generally, in terms of quick-acting property, the order is roughly: chlorantraniliprole, spinetoram, chlorfenapyr > emamectin benzoate, indoxacarb, broflanilide > cyantraniliprole, tetraniliprole > lufenuron. In terms of persistence, the order is roughly: indoxacarb, chlorantraniliprole > chlorfenapyr, spinetoram, emamectin benzoate > broflanilide, tetraniliprole > cyantraniliprole, lufenuron.

[0025] 3. Lethal effects of insecticides on adult Eocanthecona furcellata

[0026] On the first day after female Eocanthecona furcellata were exposed to 9 insecticides (χ 2 = 31.00, df = 8, P < 0.001) and the second day (χ 2 = 41.96, df = 8, P < 0.001), there were significant differences in the mortality rates (Table 4). Among them, after one day of exposure, the mortality rate of female Eocanthecona furcellata caused by spinetoram was significantly higher than that of the other 6 insecticides except indoxacarb and broflanilide; after two days of exposure, the mortality rates of female Eocanthecona furcellata caused by spinetoram and indoxacarb were significantly higher than those of chlorfenapyr, emamectin benzoate, chlorantraniliprole and tetraniliprole.

[0027] On the first day after male Eocanthecona furcellata were exposed to 9 insecticides (χ 2 = 33.26, df = 8, P < 0.001) and the second day (χ 2There were significant differences in mortality rates among them (Table 4). Among them, after one day of exposure, the mortality rate of spinetoram against male Eocanthecona furcellata was significantly higher than that of the other six insecticides except indoxacarb and lufenuron; after two days of exposure, the mortality rates of spinetoram and indoxacarb against male Eocanthecona furcellata were significantly higher than those of the other five insecticides except cyantraniliprole and broflanilide, and the mortality rate of emamectin benzoate against male Eocanthecona furcellata was the lowest, significantly lower than that of other insecticides.

[0028] Comprehensively considering the mortality rates of male and female adult Eocanthecona furcellata in the first two days, the safety order of these insecticides against Eocanthecona furcellata was roughly: emamectin benzoate, chlorfenapyr, chlorantraniliprole, tetraniliprole > cyantraniliprole, broflanilide, lufenuron > indoxacarb, spinetoram.

[0029] 4. Sublethal effects of insecticides on Eocanthecona furcellata

[0030] Combining the control efficacy of insecticides against Spodoptera frugiperda and the safety against Eocanthecona furcellata, emamectin benzoate, chlorfenapyr and chlorantraniliprole were selected to conduct sublethal effect tests.

[0031] 4.1 Effects of insecticides on the predation start time of the F0 generation of Eocanthecona furcellata

[0032] After male and female adult Eocanthecona furcellata were exposed to insecticides, the effects on the predation start time of the F0 generation of adults on the 3rd instar larvae of Spodoptera frugiperda are shown in Table 5. The predation start time of the F0 generation of adults on the 3rd instar larvae of Spodoptera frugiperda was significantly different among different treatments (χ 2 = 135.64, df = 3, 156, P < 0.001). After exposure to insecticides, the predation start time of Eocanthecona furcellata adults was significantly prolonged compared with the control, and the prolonging effect of chlorantraniliprole on the predation start time of Eocanthecona furcellata adults was significantly higher than that of chlorfenapyr and emamectin benzoate. The predation start time of the F0 generation of adults on the 3rd instar larvae of Spodoptera frugiperda was significantly different among different test sites (χ 2 = 91.04, df = 1, 154, P < 0.001), and the predation start time in the insect rearing box was significantly shorter than that on the corn plants. However, there was no significant difference in the predation start time of the F0 generation of adults on the 3rd instar larvae of Spodoptera frugiperda between male and female adults (χ 2 = 350.68, df = 1, 155, P = 0.096).

[0033] After male and female adult Eocanthecona furcellata were exposed to insecticides, the predation start time of the F0 generation of adults on the 3rd instar larvae of Spodoptera frugiperda was between different treatments and the gender of Eocanthecona furcellata (χ 2= 27.16, df = 3, 151, P < 0.001), and there were significant interaction effects between different treatments and test sites (χ 2 = 27.25, df = 3, 148, P < 0.001). Specifically, in the control and emamectin benzoate treatments, there was no significant difference in the predation start time of F0 adults on 3rd instar Spodoptera frugiperda larvae between male and female adults. However, in the chlorfenapyr treatment, the treatment time of female insects was significantly longer than that of male insects, and in the chlorantraniliprole treatment, the treatment time of male insects was significantly longer than that of female insects. In the insect rearing box, the predation start time of Cannibalocoris annulatus was significantly shorter in the chlorfenapyr and emamectin benzoate treatments than in the chlorantraniliprole treatment. On corn plants, there was no significant difference in the predation start time of Cannibalocoris annulatus among the three pesticide treatments.

[0034] 4.2 Effects of insecticides on the reproductive characteristics of F0 generation of Cannibalocoris annulatus

[0035] The number of eggs laid by F0 adults of Cannibalocoris annulatus (F = 1.371, df = 3, 30, P = 0.270), pre-oviposition period (F = 0.762, df = 3, 30, P = 0.524), oviposition duration (χ 2 = 1.490, df = 3, P = 0.684), and number of oviposition days (F = 1.160, df = 3, 30, P = 0.342) showed no significant differences among different treatments (Table 6). In addition, there were no significant differences in the lifespan of F0 female adults (F = 0.803, df = 3, 30, P = 0.502) and male adults (F = 0.824, df = 3, 30, P = 0.491) of Cannibalocoris annulatus after exposure to insecticides.

[0036] 4.2 Effects of insecticides on the growth and development of F1 generation of Cannibalocoris annulatus

[0037] After different pesticide treatments, there were significant differences in the egg hatching rate of F1 generation of Cannibalocoris annulatus (F = 6.532, df = 3, 73, P < 0.001), and only the egg hatching rate in the emamectin benzoate treatment was not significantly different from that of the CK (Table 7). There was no significant difference in the adult emergence rate of F1 generation among different treatments (χ2 = 4.79, df = 3, P = 0.188, Table 7). The egg duration (χ 2 = 34.7, df = 3, P < 0.001), nymph duration (χ 2 = 57.9, df = 3, P < 0.001), and egg-to-adult duration (χ 2 = 61.4, df = 3, P < 0.001) were all significantly different among different treatments, and the development duration in the emamectin benzoate treatment was significantly longer than that of other treatments (Table 7).

[0038] Control effect of the combined application of *Eocanthecona furcellata* (Wolff) and insecticides on *Spodoptera frugiperda* (J. E. Smith)

[0039] By comprehensively evaluating the control efficacy of insecticides against *Spodoptera frugiperda* and the safety to *Eocanthecona furcellata*, emamectin benzoate and chlorfenapyr were selected as the insecticides for combined application with *Eocanthecona furcellata*. Five experimental treatments were set up, namely (1) blank control CK; (2) emamectin benzoate treatment, that is, emamectin benzoate was applied at the seedling stage and small trumpet stage of maize, and then applied again 28 days later; (3) chlorfenapyr treatment, that is, chlorfenapyr was applied at the seedling stage and small trumpet stage of maize, and then applied again 28 days later; (4) *Eocanthecona furcellata* + emamectin benzoate treatment, that is, *Eocanthecona furcellata* was released at the seedling stage and small trumpet stage of maize, and emamectin benzoate was applied 28 days later; (5) *Eocanthecona furcellata* + chlorfenapyr treatment, that is, *Eocanthecona furcellata* was released at the seedling stage and small trumpet stage of maize, and chlorfenapyr was applied 28 days later; (6) emamectin benzoate + *Eocanthecona furcellata* treatment, that is, emamectin benzoate was applied at the seedling stage and small trumpet stage of maize, and *Eocanthecona furcellata* was released 28 days later. A completely randomized design was used, with 3 replicates for each treatment and each replicate being 333.3 square meters. There was a 15-meter interval between each plot. The five-point sampling method was used, and 20 plants were investigated at each point. The recommended application concentrations of emamectin benzoate and chlorfenapyr were 2.50 ppm and 55.00 ppm, respectively. The release amount of adult *Eocanthecona furcellata* was 40 per mu (20 male and 20 female adults).

[0040] Different prevention and control measures had significant effects on the population density of Spodoptera frugiperda (Table 8). Before prevention and control, there was no significant difference in the population base number among different treatment plots (F = 0.263, df = 5, 12, P = 0.925). One day after the first prevention and control, there were significant differences in the population density among different treatment plots (F = 107.3, df = 5, 12, P < 0.001). Among them, the population density of the treatment with insecticide applied in the first prevention and control was significantly less than that of CK and the treatment with Eocanthecona furcellata released. Seven days and 14 days after the first prevention and control, there were significant differences in the population density among different treatment plots (7 days: F = 382.3, df = 5, 12, P < 0.001; 14 days: F = 208.5, df = 5, 12, P < 0.001). Among them, the population density of the treatment with insecticide applied in the first prevention and control was still significantly less than that of CK and the treatment with Eocanthecona furcellata released. However, the population density of the treatment with Eocanthecona furcellata released was significantly less than that of CK. Twenty-one days after the first prevention and control, there were significant differences in the population density among different treatment plots (F = 68.28, df = 5, 12, P < 0.001). Among them, the largest population density was still that of CK, followed by the treatment with Eocanthecona furcellata released, and then the treatment with insecticide applied. The difference in population density between the treatment with Eocanthecona furcellata released and the treatment with insecticide applied gradually narrowed. Twenty-eight days after the first prevention and control, although there were still significant differences in the population density among different treatment plots (F = 26.34, df = 5, 12, P < 0.001), there was no significant difference in population density among the remaining 5 treatments except CK. The second prevention and control measure was implemented 28 days after the first prevention and control. Thirty-five days after the first prevention and control, there were significant differences in the population density among different treatment plots (F = 161.4, df = 5, 12, P < 0.001). Among them, the largest population density was still that of CK, followed by the treatment with emamectin benzoate + Eocanthecona furcellata (i.e., the treatment with Eocanthecona furcellata released in the second prevention and control measure), and then the other 4 treatments, and there was no significant difference in population density among these 4 treatments. Forty-two days and 48 days after the first prevention and control, there were significant differences in the population density among different treatment plots (42 days: F = 114.1, df = 5, 12, P < 0.001; 48 days: F = 116.0, df = 5, 12, P < 0.001), and the treatment with Eocanthecona furcellata + insecticide significantly reduced the population density compared with the treatment with only insecticide or insecticide + Eocanthecona furcellata.

[0041] Except for 21 d (F = 2.331, df = 4, 10, P = 0.127) and 28 d (F = 1.104, df = 4, 10, P = 0.407) after the first prevention and control, different prevention and control measures had significant effects on the field control efficacy of Spodoptera frugiperda (Table 9). Generally, the application of insecticides had obvious control efficacy against Spodoptera frugiperda. Emamectin benzoate and chlorfenapyr had good quick-acting and long-lasting effects on Spodoptera frugiperda. However, the control efficacy decreased to 66.71% - 35.21% from 21 d to 28 d after application. The quick-acting effect of releasing Eocanthecona furcellata was poor, and its long-lasting effect within 14 d was also inferior to that of insecticides. However, the control efficacy after 21 d was comparable to that of applying insecticides, and its advantage of combined use with insecticides gradually emerged 42 d after the first prevention and control. In the combined use of emamectin benzoate and Eocanthecona furcellata, the application of insecticides in the early stage could effectively reduce the population density, but after 35 d and later after the first prevention and control, the control efficacy was inferior to that of the treatment with insecticides applied in the later stage. Specifically as follows: 1 d (F = 1975, df = 4, 10, P < 0.001), 7 d (F = 168.5, df = 4, 10, P < 0.001), and 14 d (F = 37.19, df = 4, 10, P < 0.001) after the first prevention and control, there were significant differences in the field control efficacy of different prevention and control measures against Spodoptera frugiperda, and the control efficacy of the treatment with insecticides applied was significantly greater than that of CK and the treatment with Eocanthecona furcellata released. 35 d (F = 37.19, df = 4, 10, P < 0.001) and 42 d (F = 24.55, df = 4, 10, P < 0.001) after the first prevention and control, there were significant differences in the field control efficacy of different prevention and control measures against Spodoptera frugiperda, and the control efficacy of the treatment with emamectin benzoate + Eocanthecona furcellata was significantly lower than that of the other 4 treatments. 49 d after the first prevention and control, there were significant differences in the field control efficacy of different prevention and control measures against Spodoptera frugiperda (F = 24.25, df = 4, 10, P < 0.001), and the control efficacy of the treatment with Eocanthecona furcellata + insecticides was significantly higher than that of the other 3 treatments.

[0042] Table 2 Field control effect of insecticides against Spodoptera frugiperda

[0043]

[0044] Table 3 Field control effect of insecticides against Spodoptera frugiperda

[0045]

[0046]

[0047] Note: The corrected control efficacy data are mean ± standard error. Different letters after the data in the same column indicate significant differences in the corrected control efficacy of different insecticides on the same day (one-way ANOVA).

[0048] Table 4 Lethal effects of insecticides on adult Eocanthecona furcellata

[0049]

[0050] Note: Data in the table are mean ± standard error. Different letters after data in the same column indicate significant differences in the mortality of E. furcellata among different insecticides on the same day (Kruskal-Wallis test).

[0051] Table 5 Effects of insecticides on the starting time of E. furcellata adults in the F0 generation preying on Spodoptera frugiperda

[0052]

[0053] Note: Data in the table are mean ± standard error

[0054] Table 6 Effects of insecticides on the reproductive characteristics of E. furcellata adults in the F0 generation

[0055]

[0056]

[0057] Note: Data in the table are mean ± standard error. Different letters after data in the same row indicate significant differences in the reproductive characteristics of E. furcellata among different insecticides (one-way ANOVA or Kruskal-Wallis test).

[0058] Table 7 Effects of insecticides on the growth and development of E. furcellata adults in the F1 generation

[0059]

[0060] Note: Data in the table are mean ± standard error. Different letters after data in the same row indicate significant differences in the reproductive characteristics of E. furcellata among different insecticides (one-way ANOVA or Kruskal-Wallis test).

[0061] Table 8 Effects of different control measures on the population density of Spodoptera frugiperda (number per 100 plants)

[0062]

[0063] Note: Data in the table are mean ± standard error. Different letters after data in the same row indicate significant differences in the reproductive characteristics of E. furcellata among different insecticides (one-way ANOVA or Kruskal-Wallis test).

[0064] Table 9 Effects of different control measures on the field control efficacy of Spodoptera frugiperda

[0065]

[0066] Note: The data in the table are mean ± standard error (%). Different letters after the data in the same row indicate significant differences in the field control effects of different control measures on the same day (one-way ANOVA).

[0067] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for synergistically controlling fall armyworm using Pseudocerma sutchuenensis and high-efficiency and low-toxic insecticides, characterized in that: The steps include: During the corn seedling and trumpet-mouth stages, when the number of fall armyworms per 100 plants is ≥30, release adult pronghorn bugs for control; after 25 to 32 days of control, spray high-efficiency, low-toxic insecticides.

2. The method according to claim 1, characterized in that The density of the adult Psoralea corylifolia is 30 to 50 per mu.

3. The method according to claim 2, characterized in that The male-female ratio of the adult Psoralea corylifolia is 1:

1.

4. The method according to claim 1, characterized in that: The type of the high-efficiency and low-toxic insecticide is one or more of avermectin benzoate, chlorfenapyr, chlorfenapyr and tetrazobactam.

5. The method according to claim 4, characterized in that The spraying concentration of the high-efficiency and low-toxic insecticide is 2.50-55.00 ppm.

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