JP7696554B2 - Sex attractant of the fall armyworm, Pseudokirchneriella nigricans - Google Patents

Description

The present invention relates to an attractant for adult males of the fall armyworm, and more specifically, to a composition for attracting males of the fall armyworm, a composition for disrupting male-female mating of the fall armyworm, a composition for enhancing the attractive effect of an attractant for males of the fall armyworm , a device for capturing males of the fall armyworm , a method for attracting males of the fall armyworm , and a method for disrupting male-female mating of the fall armyworm .

The fall armyworm (Spodoptera frugiperda) is a pest thought to be native to Central and South America that attacks a variety of plants, mainly those of the Gramineae family, such as corn and sugarcane. In recent years, its distribution has expanded globally, and its first invasion of Japan was confirmed in 2019. It is a pest with high flying ability, and adults arrive on air currents from both within and outside Japan and lay eggs and cause damage, so it is necessary to accurately understand its arrival and occurrence in order to predict and minimize damage.

Traps that use attractants such as sex pheromones are used as a means of monitoring the arrival and occurrence of pest insects. Sex pheromones are chemical substances that are generally secreted by adult female insects, and they have a species-specific and strong attractant effect on adult male insects of the same species. Therefore, if the chemical structure of sex pheromones could be clarified and they could be industrially synthesized and sex pheromone traps could be supplied, it would be possible to efficiently and easily investigate the occurrence of pest insects (for example, Patent Document 1). It is also known that synthetic sex pheromones can be used as preparations that disrupt the communication of information regarding mating between males and females (for example, Patent Document 2), and registration of such synthetic sex pheromones as pesticides is also underway.

The sex pheromone components produced by adult females of the armyworm moth are (Z)-9-tetradecenyl acetate (Z9-14Ac), (Z)-7-dodecenyl acetate (Z7-12Ac), (Z)-11-hexadecenyl acetate (Z11-16Ac), and (Z)-9-dodecenyl acetate (Z9-12Ac) (see, for example, Non-Patent Document 1). Of these, only two components, Z9-14Ac and Z7-12Ac, are capable of attracting adult males, but a mixture containing all four of the above components is more attractive (see, for example, Non-Patent Document 2). However, sex pheromone traps using a formulation containing the above four ingredients as an attractant often mistakenly attract moths of the genera Mythimuna and Leucania (e.g., Non-Patent Document 2), and are known to be contaminated with the grass cutworm Mythimuna loreyi in particular (e.g., Non-Patent Document 3). The contamination of other species significantly reduces the work efficiency of infestation surveys using pheromone traps.

In addition, Non-Patent Documents 4 and 5 state that synthesized (Z,E)-9,12-tetradecadienyl acetate (Z9E12-14Ac) was used in combination with Z9-14Ac to attract male fall armyworms, but they do not state that Z9E12-14Ac is secreted by female fall armyworms, nor do they state that Z9E12-14Ac has any attraction (cross-reactivity) to fall armyworms.

Patent No. 4734553 JP 2020-66601 A

Tumlinson JH, Mitchell ER, Teal PEA et al (1986) Sex pheromone of fall armyworm, Spodoptera frugiperda (J.E. Smith): Identification of components critical to attraction in the field. J Chem Ecol 12:1909-1926. https://doi.org/10.1007/BF01041855. Fleischer SJ, Harding CL, Blom PR et al (2005) Spodoptera frugiperda pheromone lures to avoid nontarget captures of Leucania phragmatidicola. J Econ Entomol 98:66-71. https://doi.org/10.1093/jee/98.1.66 Wakamura S, Arakaki N, Yoshimatsu S (2020) Sex pheromone of the fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae) of a “Far East” population from Okinawa, Japan. Appl Entomol Zool 56:19-25. https://doi.org/10.1007/s13355-020-00703-9 Mitchell ER, Doolittle RE (1976) Sex pheromones of Spodoptera exigua S. eridania, and S. frugiperda: Bioassay for field activity. J Econ Entomol 69:324-326. https://doi.org/10.1093/jee/69.3.324 Blassioli-Moraes MC, Borges M, Viana AR et al (2016) Identification and field evaluation of the sex pheromone of a Brazilian population of Spodoptera cosmioides. Pesq. Agropec. Bras. 51:545-554. https://doi.org/10.1590/S0100-204X2016000500015

If it were possible to selectively attract male fall armyworms and suppress the erroneous attraction of fall armyworms, it would be possible to efficiently monitor and control fall armyworms. Therefore, an object of the present invention is to provide a composition that selectively attracts male fall armyworms.

As a result of intensive research aimed at solving the above problems, the present inventors have detected and identified trace amounts of Z9E12-14Ac in the sex pheromone gland extract of adult females of the fall armyworm, and have found that this compound enhances the attraction of adult males of the fall armyworm by known sex pheromones and suppresses the erroneous attraction of the fall armyworm, thereby completing the present invention. That is, the present invention provides the following composition, trapping device, and method.
[1] (Z)-9-tetradecenyl acetate (Z9-14Ac),
(Z)-7-dodecenyl acetate (Z7-12Ac),
(Z,E)-9,12- tetradecadienyl acetate ( Z9E12-14Ac ).
[2] The content ratio of Z9-14Ac and Z9E12-14Ac is 1:0.2×10 ⁻⁵ to 0.02 by mass ratio, or
The content ratio of Z9-14Ac, Z7-12Ac, and Z9E12-14Ac is 1:0.1× ^10-2 to 0.1:0.2× ^10-5 to 0.02 by mass ratio;
The composition described in [1] above.
[3] The composition according to [2] above, further comprising (Z)-11-hexadecenyl acetate (Z11-16Ac) and/or (Z)-9-dodecenyl acetate (Z9-12Ac).
[4] The composition according to [1] above, further comprising Z11-16Ac and/or Z9-12Ac.
[5] The composition according to any one of [1] to [4] above, wherein the composition is in the form of a solution or emulsion, or is in the form of being impregnated in a sustained release carrier.
[6] A composition for enhancing the attractant effect of a male attractant for the fall armyworm , comprising Z9E12-14Ac,
The composition, wherein the attractant comprises Z9-14Ac and Z7-12Ac.
[7] The composition according to [6], wherein the attractant further contains Z11-16Ac and/or Z9-12Ac.
[8] A capture device for males of the fall armyworm , including Z9-14Ac, Z7-12Ac, and Z9E12-14Ac.
[9] The capture device described in [8] above, further comprising Z11-16Ac and/or Z9-12Ac.
[10] A method for attracting males of the fall armyworm moth or disrupting male-female mating of the fall armyworm moth , comprising the step of applying a composition containing Z9-14Ac, Z7-12Ac, and Z9E12-14Ac to a location where males of the fall armyworm moth are attracted.
[11] The method according to [10] above, wherein the composition further comprises Z11-16Ac and/or Z9-12Ac.

According to the present invention, by using Z9E12-14Ac in combination with Z9-14Ac and Z7-12Ac, it is possible to improve the attraction and species selectivity of adult males of the fall armyworm. Therefore, it is possible to efficiently monitor and control the fall armyworm.

The present invention will now be described in further detail.
The composition of the present invention comprises
(Z)-9-tetradecenyl acetate (Z9-14Ac),
(Z)-7-dodecenyl acetate (Z7-12Ac),
and (Z,E)-9,12-tetradecadienyl acetate (Z9E12-14Ac). These compounds (hereinafter, the three compounds are collectively referred to as "core compounds") are components contained in the sex pheromone gland extract of adult females of the pest insect , Nectaria campestris , and function as sex pheromones released by the adult females. Therefore, the composition of the present invention can be used to attract males of Nectaria campestris . Therefore, the composition can be used for investigating the occurrence of Nectaria campestris or for attracting and capturing (or attracting and killing) Nectaria campestris.

In addition, if the sex pheromone released by female fall armyworms is artificially filled in their habitat or a place where they are suspected to live, male fall armyworms will be unable to distinguish the female's true habitat and will be unable to reach her. Therefore, the composition of the present invention can also be used to disrupt communication between males and female fall armyworms.

The content ratio of the core compounds is not particularly limited as long as it is capable of attracting males of the fall armyworm or disrupting male-female communication of the fall armyworm , but for example, the content ratio of Z9-14Ac and Z9E12-14Ac may be about 1: about 0.2×10 ^-5 to about 0.02, preferably about 1: about 0.1×10 ^-3 to about 0.01, in mass ratio. Alternatively, the content ratio of Z9-14Ac, Z7-12Ac, and Z9E12-14Ac may be about 1: about 0.1×10 ^-2 to about 0.1: about 0.2×10 ^-5 to about 0.02, preferably about 1: about 0.5×10 ^-2 to about 0.05: about 0.1×10 ^-3 to about 0.01.

In one embodiment, the composition of the present invention further comprises (Z)-11-hexadecenyl acetate (Z11-16Ac) and/or (Z)-9-dodecenyl acetate (Z9-12Ac). These additional compounds are also components contained in the sex pheromone gland extract of adult females of the fall armyworm , and function as sex pheromones released by the adult females. The content ratio of the additional compounds is not particularly limited, and for example, the content ratio of Z9-14Ac and Z11-16Ac may be about 1: about 0.5×10 ^-2 to about 1 by mass, and the content ratio of Z9-14Ac and Z9-12Ac may be about 1: about 0.5×10 ^-3 to about 0.05 by mass.

In one embodiment, the composition of the present invention further comprises an organic solvent. The organic solvent may be any organic solvent commonly used in the art, without particular limitation. For example, the organic solvent may be a hydrocarbon organic solvent such as pentane or hexane.

In one embodiment, the composition of the present invention is in the form of a solution or emulsion. The total concentration of the core compound in the composition of the present invention is not particularly limited as long as the desired action is achieved, but for example, when the purpose is to investigate the occurrence of or attract and capture (or attract and kill) the fall armyworm, the total concentration of the core compound in the composition of the present invention may be, for example, about 0.001 to about 100.0 mg/mL, and preferably about 0.01 to about 10 mg/mL. When disrupting the communication between males and females of the fall armyworm, the total concentration of the core compound in the composition of the present invention may be, for example, about 0.1 to about 1000 mg/mL, and preferably about 0.5 to about 500 mg/mL.

In one embodiment, the composition of the present invention is in a form impregnated in a sustained release carrier. The sustained release carrier may be any of those commonly used in the art, without particular limitation. For example, the sustained release carrier may be a container such as a cap (septum), a thin tube, a laminated bag, or a capsule, made of a material having a release amount control function, such as rubber, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, or polyvinyl chloride, and is preferably a septum or thin tube made of rubber or polyethylene.

The total impregnation amount of the core compound per sustained release carrier is not particularly limited as long as the desired action is achieved, but for example, when the purpose is to investigate the occurrence of or attract and capture (or attract and kill) the fall armyworm, it may be about 0.0001 to about 100 mg, and preferably about 0.001 to about 10 mg, per about 1 cm ³ of sustained release carrier. When the purpose is to disrupt communication between males and females of the fall armyworm, the total impregnation amount of the core compound per sustained release carrier may be, for example, about 1.0 to about 1000 mg, and preferably about 50 to about 500 mg.

The sustained release carrier can be used in combination with a trap for capturing pests (attached to the trap). The trap can be any trap commonly used in the art, without any particular limitations. For example, the trap may be a sticky trap, a water basin trap, or a suction trap, and is preferably a sticky trap. There is no particular limitation on the number of sustained release carriers attached to the trap, and it may be adjusted appropriately depending on the size and purpose of use of each, but for example, about 1 to about 10 sustained release carriers may be attached to the trap.

The composition of the present invention, particularly the composition impregnated in the sustained release carrier, may be installed outdoors. The installation density of the sustained release carrier outdoors is not particularly limited, but for example, when one sustained release carrier is attached to the trap for the purpose of investigating the occurrence of the fall armyworm or attracting and capturing (or killing) the fall armyworm, the installation density of the sustained release carrier outdoors may be, for example, about 1 to about 1000 per 10 ares, preferably about 10 to about 500 per 10 ares. The interval between the sustained release carriers is not particularly limited, but may be, for example, about 1 to about 100 m, preferably about 5 to about 15 m. When disrupting communication between males and females of the fall armyworm, the installation density of the sustained release carrier outdoors may be, for example, about 50 to about 500 per 10 ares, and the interval between the sustained release carriers may be, for example, about 0.5 to 100 m, preferably about 1.4 to about 10 m.

The installation position of the composition of the present invention, particularly the composition impregnated in the sustained release carrier, is not particularly limited, but may be, for example, at a height of about 10 to about 200 cm above the ground, and preferably at a height of about 30 to about 160 cm. In addition, the installation time of the composition is not particularly limited, but may be, for example, during the arrival of adult fall armyworms.

In one embodiment, the composition of the present invention is in a form impregnated into agricultural or horticultural materials such as nets and ropes. When materials impregnated with the composition of the present invention are widely installed in a field, they are particularly useful for disrupting mating between males and females of the fall armyworm. The method of impregnating the materials is not particularly limited, and for example, the composition in a solution state may be impregnated by spraying or applying it to the materials. The amount of the core compound to be sprayed or applied is not particularly limited as long as the desired effect is achieved, and for example, when disrupting mating between males and females of the fall armyworm, the total amount of the core compound impregnated in the materials when the materials are installed in a field may be about 2.5 to about 250 g per 10 ares.

The composition of the present invention may further contain any excipients and/or additives commonly used in the art, and may further contain other active ingredients that attract moths and/or other active ingredients that disrupt male-female communication of moths, so long as the purpose of the present invention is not impaired.

In another aspect, the present invention also relates to a composition for enhancing the attractant effect of an attractant for males of Fall Armyworm , comprising Z9E12-14Ac. The attractant comprises Z9-14Ac and Z7-12Ac, and may further comprise Z11-16Ac and/or Z9-12Ac, if desired. Z9E12-14Ac can selectively enhance the attractiveness of males of Fall Armyworm without falsely attracting males of Fall Armyworm. The ratio of each compound used is not particularly limited, and is as described above for the content ratio of each compound in the composition for attracting males of Fall Armyworm or the composition for disrupting male-female mating of Fall Armyworm .

In another aspect, the present invention also relates to a trapping device for males of the fall armyworm , comprising Z9-14Ac, Z7-12Ac, and Z9E12-14Ac. The trapping device can be used for investigating the occurrence of the fall armyworm or for attracting and trapping (or killing) the fall armyworm. The content ratio of the above three compounds is not particularly limited and is as described above for the composition of the present invention.

In one embodiment, the trapping device of the present invention may further comprise the sustained release carrier and/or the trap described above. The installation time of the trapping device of the present invention is not particularly limited, but may be installed, for example, during the arrival time of adult fall armyworms. In another embodiment, the trapping device of the present invention further comprises Z11-16Ac and/or Z9-12Ac. The content ratio of these additional compounds is not particularly limited and is as described above for the composition of the present invention.

In another aspect, the present invention also relates to a method for attracting males of the fall armyworm or a method for disrupting male-female mating of the fall armyworm , comprising a step of applying a composition containing Z9-14Ac, Z7-12Ac, and Z9E12-14Ac to a place where males of the fall armyworm are attracted. The composition used in the method of the present invention is as described above as the composition of the present invention. The method of applying the composition is not particularly limited, and may be, for example, a method of diluting the composition in a solvent capable of uniformly dispersing the composition and spraying it on a target place, or a method of impregnating the composition into the above-mentioned sustained release carrier and placing it on a target place.

The present invention will be described in detail below with reference to examples, but the scope of the present invention is not limited to these examples.

1. Analysis of sex pheromone gland extracts from adult females of the fall armyworm Emerged adult females of the fall armyworm were isolated from adult males and fed a 10% honey solution at 23°C. The lights in the rearing room were turned on at 6 am and turned off at 10 pm. Between 11 pm and 12 pm on the second to fourth day after emergence, abdominal terminal segments containing sex pheromone glands were excised from 112 adult females. These were immersed in approximately 4 mL of hexane for 30 minutes and then filtered to obtain a crude extract.

The crude extract was concentrated to approximately 0.03 mL using a rotary evaporator and then injected into a column chromatograph packed with silica gel (0.2 g). The extract was then fractionated and eluted using 2 mL of hexane containing 0, 5, 15, or 50% diethyl ether.

Tridecyl acetate (20 ng) was added to the 5% diethyl ether fraction as an internal standard, and the fraction was reconcentrated to approximately 0.1 mL using a rotary evaporator. 0.003 mL of the fraction was analyzed using a gas chromatograph-mass spectrometer (Agilent) equipped with a DB-WAX column (inner diameter 0.25 mm, length 30 m). When the temperature in the column oven was raised from an initial temperature of 60°C (held for 1 minute) to 230°C at a rate of 10°C per minute, the known sex pheromone components Z9-14Ac, Z7-12Ac, Z11-16Ac, and Z9-12Ac were detected at 18.0 minutes, 15.4 minutes, 20.3 minutes, and 15.6 minutes, respectively. Furthermore, trace components with EI mass spectra similar to these components were detected at 18.9 minutes. The content ratio of this trace component was approximately 0.2% of the peak area ratio in the gas chromatogram relative to Z9-14Ac, which had the highest content.

The EI mass spectrum [m/z (relative intensity %)] of the above minor components was as follows:
43 (92.9), 55 (60.7), 67 (100), 81 (95.0), 95 (56.8), 107 (19.2), 121 (26.0), 135 (16.7), 149 (8.5), 163 (3.3), 192 (12.8), 252 (1.0)
Since this spectrum and retention time in gas chromatography matched those of the synthetic product Z9E12-14Ac, the minor component was identified as Z9E12-14Ac.

2. Attraction test 1
Several compounds among Z9-14Ac, Z7-12Ac, Z11-16Ac, Z9-12Ac, and Z9E12-14Ac were mixed to prepare 0.2 mL of a hexane solution (attractant), and the attractant was impregnated into a rubber septum (test groups A to E). Then, one rubber septum was attached to a commercially available SE trap (adhesive plate; 24 cm x 30 cm) as an attractant source to prepare a trapping device. Fifteen of these trapping devices were placed outdoors and left for one week, and the number of captured male adults of the fall armyworm and the white armyworm was counted. This test was repeated six times for nine of the trapping devices, and 21 times for six of the trapping devices. The composition of each attractant (content of the above compound) and the results are shown in Table 1.

Conventional attractants containing Z9-14Ac, Z7-12Ac, Z11-16Ac, and Z9-12Ac (test group A) attracted more Fall Armyworms than attractants containing Z9-14Ac and Z7-12Ac (test group B), but at the same time, they also mistakenly attracted Fall Armyworms. In contrast, as can be seen from a comparison between test groups B and D, the addition of Z9E12-14Ac improved the attractiveness of Fall Armyworms only, without increasing the attractiveness of Fall Armyworms. Furthermore, a comparison between test groups A and C showed that the addition of Z9E12-14Ac suppressed the attractiveness of Fall Armyworms, but increased the attractiveness of Fall Armyworms.

3. Attraction test 2
The trapping devices were prepared in the same manner as in Attraction Test 1, except that the attractant of Test Group D and attractants with different contents of Z9E12-14Ac (Test Groups F to H) were used. Six of these trapping devices were set up outdoors and left for one week, and the number of captured adult males of the armyworm and the white armyworm was counted, and this test was repeated eight times. The composition of each attractant and the results are shown in Table 2.

All test groups were able to attract the fall armyworm, and the false attraction of the fall armyworm was suppressed. In particular, when the content of Z9E12-14Ac was 0.2% of the content of Z9-14Ac, the attraction of the fall armyworm was significantly higher.

4. Attraction Test 3
In order to confirm the contribution of each compound contained in the attractant, the attraction of the fall armyworm by the attractants of test groups B, D, and E, the attractant containing Z9-14Ac (test group I), and the attractant containing Z9-14Ac and Z9E12-14Ac (test group J) was investigated using a wind tunnel in a laboratory. Specifically, air was flowed at a constant wind speed (0.25 cm per second) in a wind tunnel (length 66 cm x diameter 11.5 cm) installed in a laboratory, and a rubber septum impregnated with each attractant was placed on the upwind side as an attractant source, and the flight behavior of male fall armyworm adults released on the downwind side was observed. The composition of each attractant and the results are shown in Table 3.

Compared to a negative control attractant that did not contain any of the compounds (Test Group E), only the attractant containing the core compounds Z9-14Ac, Z7-12Ac, and Z9E12-14Ac (Test Group D) significantly activated upwind flight behavior, and the combination of just two of these components did not significantly activate upwind flight behavior. The attractant of Test Group B attracted a certain number of fall armyworms in the outdoor attraction test 1, but in the wind tunnel test conducted in a limited space in the laboratory, no statistically significant difference was observed in the response to the negative control (Test Group E), which is thought to be the result of random flight behavior. Despite these limitations, when the above core compounds were used simultaneously, a significant difference was observed in the attractant activity for adult males of the fall armyworm, and the attractant effect of the combination of the three compounds that make up the core compound is remarkable and could not have been predicted from conventional technology. In other words, Z9E12-14Ac can significantly enhance the attractant effect of attractants containing Z9-14Ac and Z7-12Ac.

From the above, it was found that the attraction and species selectivity of adult male fall armyworms can be improved by using Z9E12-14Ac in combination with Z9-14Ac and Z7-12Ac. This makes it possible to efficiently monitor and control fall armyworms.

Claims (14)

(Z)-9-tetradecenyl acetate (Z9-14Ac),
(Z)-7-dodecenyl acetate (Z7-12Ac),
(Z,E)-9,12-tetradecadienyl acetate (Z9E12-14Ac) , and
The content ratio of Z9-14Ac, Z7-12Ac, and Z9E12-14Ac is 1:0.1×10-2 ^to 0.1:0.2× ^10-5 to 0.02 by mass ratio;
A composition for attracting male fall armyworms and/or disrupting male-female mating of fall armyworms . The content ratio of Z9-14Ac , Z7-12Ac, and Z9E12-14Ac is 1:0.5×10-2 ^to 0.05:0.1× ^10-3 to 0.01 by mass ratio;
The composition of claim 1. The composition according to claim 2, further comprising (Z)-11-hexadecenyl acetate (Z11-16Ac) and/or (Z)-9-dodecenyl acetate (Z9-12Ac). The composition of claim 1 further comprising Z11-16Ac and/or Z9-12Ac. The composition according to any one of claims 1 to 4, wherein the composition is in the form of a solution or emulsion, or is impregnated in a sustained release carrier. A composition for enhancing the attractant effect of a male attractant of the fall armyworm , comprising Z9E12-14Ac,
The attractant comprises Z9-14Ac and Z7-12Ac; and
The composition , wherein the amount of Z9E12-14Ac relative to the attractant is such that the content ratio of Z9-14Ac, Z7-12Ac, and Z9E12-14Ac is 1:0.1×10 ⁻² to 0.1:0.2×10 ⁻⁵ to 0.02 by mass . The amount of Z9E12-14Ac relative to the attractant is such that the content ratio of Z9-14Ac, Z7-12Ac, and Z9E12-14Ac is 1:0.5×10 in mass ratio. ^-2 ~0.05: 0.1 x 10 ^-3 The composition of claim 6, in an amount of from about 0.01 to about 0.01. The composition of claim 6 or 7 , wherein the attractant further comprises Z11-16Ac and/or Z9-12Ac. A trapping device for males of the fall armyworm , comprising Z9-14Ac, Z7-12Ac, and Z9E12-14Ac ,
A capture device, in which the content ratio of Z9-14Ac, Z7-12Ac, and Z9E12-14Ac is 1:0.1×10 ⁻² to 0.1:0.2×10 ⁻⁵ to 0.02 by mass . The content ratio of Z9-14Ac, Z7-12Ac, and Z9E12-14Ac is 1:0.5×10 by mass ratio. ^-2 ~0.05: 0.1 x 10 ^-3 10. The capture device of claim 9, wherein the .alpha.- The capture device of claim 9 or 10 , further comprising Z11-16Ac and/or Z9-12Ac. 1. A method for attracting males of Fall Armyworm or disrupting male-female mating of Fall Armyworm , comprising the step of applying a composition comprising Z9-14Ac, Z7-12Ac, and Z9E12-14Ac to a locus for attracting males of Fall Armyworm ,
The method as described above , wherein the content ratio of Z9-14Ac, Z7-12Ac, and Z9E12-14Ac in the composition is, in mass ratio, 1:0.1×10 ⁻² to 0.1:0.2×10 ⁻⁵ to 0.02. The content ratio of Z9-14Ac, Z7-12Ac, and Z9E12-14Ac in the composition is 1:0.5×10 by mass ratio. ^-2 ~0.05: 0.1 x 10 ^-3 The method of claim 12, wherein the ratio is 0.01 to 0.01. The method of claim 12 or 13 , wherein the composition further comprises Z11-16Ac and/or Z9-12Ac.