Use of phenylacetonitrile as a synergist for Ips subelongatus Motschulsky attractant

Abstract

The present invention provides the use of phenylacetonitrile as a synergist for the attractant of Ips typographus. The attractant composed of (S)-(–)-ipsenol, (S)-(+)-ipsdienol and phenylacetonitrile provided by the present invention can increase the trapping amount by 3-5 times compared with the attractant composed of (S)-(–)-ipsenol and (S)-(+)-ipsdienol, and also has a better attracting effect compared with the attractant added with myrcene and (S)-β-pinene. The attractant of the present invention also has the advantages of strong specificity, long effective period, good stability, environmental friendliness, etc., and is suitable for population monitoring and large-area green prevention and control of Ips typographus without being affected by terrain and topography. And due to the reduction in the use of (S)-(–)-ipsenol and (S)-(+)-ipsdienol, the cost of the attractant for Ips typographus is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of biological control, and particularly relates to the use of phenylacetonitrile as a synergist for Ips subelongatus Motschulsky attractant. Background Art

[0002] Ips subelongatus Motschulsky belongs to the genus Ips of the family Curculionidae in the order Coleoptera. For a long time, the larch forest ecosystem in China has been severely damaged by Ips subelongatus Motschulsky; this pest mainly bores into the phloem of various larches and can cause the death of larches in a short period. The main hosts of Ips subelongatus Motschulsky include Larix gmelinii Kuzen., L. olgensis Henry, L. principis-rupprechtii Mayr., L. kaempferi Carr., etc. Recent studies have shown that Ips subelongatus Motschulsky has the phenomenon of transferring hosts and can damage Pinus sylvestris var. mongolica Litv., Picea sp. and other Pinaceae plants, especially when the population density is large.

[0003] At present, the population monitoring and control of Ips subelongatus mainly rely on the trapping with its aggregation pheromone, and it has been widely promoted and applied in Jilin, Heilongjiang, Inner Mongolia, Hebei, Xinjiang and other places. So far, the research on the aggregation pheromone of Ips subelongatus mainly includes the structural identification of aggregation pheromone, the behavioral activity test and the field application level. For example, the components of the aggregation pheromone of Ips subelongatus (European population) were identified as (-)-ipsenol, (+)-ipsdienol and 3-methyl-3-buten-1-ol (Francke et al., 1983). After 2000, a large number of studies confirmed that the essential components of the aggregation pheromone of Ips subelongatus in Northeast China were 97% (S)-(-)-ipsenol and 97% (S)-(+)-ipsdienol, and 3-methyl-3-buten-1-ol had no obvious synergistic effect on these two components (Zhang et al., 2007; Song et al., 2011; Chen et al., 2016; Fang et al., 2020). In addition, there have also been certain research progresses in the electrophysiological activity test, trapping or repelling test of Ips subelongatus using allelochemicals. For example, the terpenoid volatiles of larch (such as S-α-pinene, 3-carene, p-cymene, terpinolene) can stimulate the antennal potential activity of Ips subelongatus (Chen Dafeng et al., 2013), and S-β-pinene and myrcene have the effect of enhancing trapping, while S-α-pinene, R-α-pinene and terpinolene have neither synergistic effect nor inhibitory effect (Li Yejing et al., 2016; Fang et al., 2020); in addition, trans-verbenol, cis-3-hexen-1-ol, linalool and cis-verbenol all have very strong inhibitory effects on the aggregation behavior of Ips subelongatus. Thus, in order to improve the comprehensive management level against Ips subelongatus, scientific researchers have always been very concerned about the research on the aggregation pheromone, synergist and repellent of Ips subelongatus. However, the current R & D in this area mainly focuses on host and plant green leaf volatiles, and it is completely unknown whether other types of chemical volatile components have a high synergistic effect on the components of the aggregation pheromone of Ips subelongatus.

[0004] In addition, the production costs of 97% (S)-(-)-ipsenol and 97% (S)-(+)-ipsdienol are relatively high. Therefore, finding allelochemicals that can significantly enhance the effect is also very crucial for reducing the usage amounts of these two essential components, which helps to reduce the production and application costs of the lures for Ips subelongatus. In short, in order to significantly increase the trapping amount of the aggregation pheromone lures for Ips subelongatus in the field, a practical biological control product is urgently needed. Summary of the Invention

[0005] To solve the above problems, the present invention provides the following technical solutions:

[0006] The present invention provides a use of phenylacetonitrile as a synergist for Ips typographus attractant. The Ips typographus attractant includes (S)-(–)-ipsenol and (S)-(+)-ipsdienol. Specifically, the mass ratio of phenylacetonitrile to (S)-(–)-ipsenol and (S)-(+)-ipsdienol is 0.04 - 4:0.02 - 0.04:0.02 - 0.04.

[0007] The present invention also provides an Ips typographus attractant, which includes the following components in parts by weight: 0.02 - 0.04 parts of 97% (S)-(–)-ipsenol, 0.02 - 0.04 parts of 97% (S)-(+)-ipsdienol, and 0.04 - 4 parts of phenylacetonitrile. Preferably, the attractant includes the following components in parts by weight: 0.02 parts of 97% (S)-(–)-ipsenol, 0.02 parts of 97% (S)-(+)-ipsdienol, and 4 parts of phenylacetonitrile.

[0008] The present invention also provides a lure core for attracting Ips typographus, and the aforementioned attractant is provided in the lure core.

[0009] Specifically, the lure core further includes one or both of the following (1) - (2):

[0010] (1) The dosage of 97% (S)-(–)-ipsenol in a single lure core is 20 mg; the dosage of 97% (S)-(+)-ipsdienol is 20 mg; the dosage of phenylacetonitrile is 4000 mg;

[0011] (2) The lure core further includes a slow-release carrier, and the slow-release carrier is a polyethylene plastic bag; a degreased cotton is arranged inside the slow-release carrier, and the aforementioned attractant is adsorbed on the degreased cotton.

[0012] More specifically, the dosage of degreased cotton in a single lure core is 3 g; and / or, the thickness of the polyethylene plastic bag is 20 silk, the length is 150 mm, and the width is 70 mm.

[0013] The present invention also provides a preparation method of the aforementioned lure core, which includes the following steps:

[0014] Place absorbent cotton in a polyethylene plastic bag, then drop the aforementioned attractant onto the absorbent cotton, and seal it to obtain the lure core. Specifically, dissolve 20 mg of 97% (S)-(–)-ipsenol and 20 mg of 97% (S)-(+)-ipsdienol in 4000 mg of phenylacetonitrile according to the required amount. After mixing the above solution evenly, directly drop it into the absorbent cotton in a black polyethylene plastic bag carrier with a thickness of 20 filaments, and seal it with an aluminum foil bag to prepare the lure core.

[0015] The present invention also provides an application of the aforementioned lure core in trapping Ips acuminatus. Specifically, the application includes: hanging the lure core in the forest, and the number of lures hung per mu is 2 - 3. More specifically, a funnel-shaped Ips beetle trap is used, the flared mouth connecting the collection bottle is sleeved on the lower part of the funnel and connected to the collection bottle. The lure core is preferably fixed at the upper-middle part of the trap, and then the trap is hung in an open area of the forest. Hang 1 lure core at the middle position of the top of the trap, the height of the collection bottle of the trap from the ground is 50 cm, and the distance between the traps is 30 - 50 m.

[0016] The beneficial effects of the present invention are as follows:

[0017] The high-efficiency attractant provided by using phenylacetonitrile as a synergist in the present invention can attract a large number of Ips acuminatus, and has the advantages of strong specificity, long-lasting effect, good stability, environmental friendliness, etc. It is suitable for population monitoring and large-area control of Ips acuminatus, and is not affected by terrain and topography. And because the usage amounts of (S)-(–)-ipsenol and (S)-(+)-ipsdienol are reduced, the cost is lowered. Description of the Drawings

[0018] Figure 1 It is the test result of the bioactivity evaluation of different dosages of phenylacetonitrile in the attractant in Example 1 on Ips acuminatus;

[0019] Figure 2 It is the evaluation of the synergistic effect of phenylacetonitrile on different dosages of aggregation pheromone lures of Ips acuminatus in Example 2;

[0020] Figure 3 It is the test result of the long-term synergistic effect evaluation of phenylacetonitrile on the attractant of Ips acuminatus in Example 3;

[0021] Figure 4 It is the comparison of the influence of phenylacetonitrile and other plant-derived synergists on the attracting effect of aggregation pheromone lures of Ips acuminatus in Example 4;

[0022] Figure 5 It is the influence of phenylacetonitrile on the attracting effect of aggregation pheromone lures of Ips acuminatus at different experimental sites in Example 5. Detailed Embodiments

[0023] The technical solutions provided by the present invention will be described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0024] The larch bark beetle aggregation pheromone attractants prepared in the following examples all use commercially available 97% (S)-(–)-ipsenol, with a chemical purity and isomeric purity both greater than 97%, 97% (S)-(+)-ipsdienol, with a chemical purity and isomeric purity both greater than 97%; commercially available phenylacetonitrile, with a chemical purity and isomeric purity both greater than 95%; commercially available myrcene, with a chemical purity and isomeric purity both greater than 95%; commercially available (S)-β-pinene, with a chemical purity and isomeric purity both greater than 95%. Example 1: Influence of different dosages of phenylacetonitrile on the attracting effect of larch bark beetle aggregation pheromone lure cores

[0025] The following 6 treatments were prepared according to the test requirements:

[0026] Treatment 1: Blank treatment, the lure core carrier only contains absorbent cotton and does not add any chemical components;

[0027] Treatment 2: Add 4000 mg of phenylacetonitrile to the lure core carrier;

[0028] Treatment 3: Add 20 mg of 97% (S)-(–)-ipsenol and 20 mg of 97% (S)-(+)-ipsdienol to the lure core carrier;

[0029] Treatment 4: Add 20 mg of 97% (S)-(–)-ipsenol and 20 mg of 97% (S)-(+)-ipsdienol to the lure core carrier; then add 40 mg of phenylacetonitrile;

[0030] Treatment 5: Add 20 mg of 97% (S)-(–)-ipsenol and 20 mg of 97% (S)-(+)-ipsdienol to the lure core carrier; then add 400 mg of phenylacetonitrile;

[0031] Treatment 6: Add 20 mg of 97% (S)-(–)-ipsenol and 20 mg of 97% (S)-(+)-ipsdienol to the lure core carrier; then add 4000 mg of phenylacetonitrile.

[0032] (1) 97% (S)-(–)-ipsenol, 97% (S)-(+)-ipsdienol, and phenylacetonitrile were prepared according to the above ratios to obtain attractants with different ratios.

[0033] (2) Preparation and storage of lure cores: The attractants with different treatments mixed evenly were respectively added to the absorbent cotton in a 20-filament black polyethylene plastic bag weighing 3 g. The prepared lure cores were sealed and packaged with aluminum foil bags and stored refrigerated at 4°C.

[0034] (3) Field application of the lure core:

[0035] a) Experiment time and location: From July 1st to August 1st, 2020, at Saihanba Mechanical Forest Farm, Chengde City, Hebei Province.

[0036] b) Fabrication of the trap: The trap is mainly a funnel-shaped bark beetle trap, purchased from Beijing ZhongJieSiFang Biological Technology Co., Ltd. The bottom of the funnel trap is connected to the insect collection bottle.

[0037] c) Suspension of the lure core: Hang 1 lure core at the middle position from the top of the funnel-shaped bark beetle trap.

[0038] d) Field setting of the trap: Set 3 replicates for each experimental treatment. The traps are set at the edge of the larch forest, and the distance between the traps is approximately 30 m. Insert two bamboo poles with a length of 2 m and a diameter of 5 cm into the soil to a depth of about 50 cm. The distance between the two bamboo poles is 30 cm, and then fix the trap between the two bamboo poles. The insect collection bottle of the trap is 50 cm above the ground.

[0039] e) Data investigation and emptying of the trap: Set 3 replicates for each treatment in this experiment. The average number of Ips typographus trapped in each treatment is the average of the numbers trapped in 3 traps. According to the weather conditions, observe the number of bark beetles in the insect collection bottle every 2 - 3 days. After counting, take the trapped bark beetles to the laboratory in a plastic box.

[0040] From the analysis of the trapping effect (such as Figure 1As can be seen from the figure (shown), the blank treatment (Treatment 1) does not have attractive biological activity against Ips typographus, and the use of phenylacetonitrile alone (Treatment 2) has no attractive activity against Ips typographus. However, Treatment 3 has a good trapping effect on Ips typographus, with an average trapping amount of 39 individuals. The trapping effects of Treatments 4, 5, and 6 on Ips typographus are better than that of Treatment 3, especially for Treatment 6 compared with Treatment 3, and the synergistic effect is very significant. This experiment shows that two aggregation pheromone components, 97% (S)-(–)-ipsenol and 97% (S)-(+)-ipsdienol, have good attractive effects on Ips typographus. When phenylacetonitrile is added to these two components, the formulated high-efficiency attractant core for Ips typographus can significantly increase the trapping amount, with the highest increase of 4 - 5 times. This experiment shows that phenylacetonitrile alone cannot attract Ips typographus, while the mixture of 97% (S)-(–)-ipsenol, 97% (S)-(+)-ipsdienol, and phenylacetonitrile can trap a large number of Ips typographus in the forest, indicating that phenylacetonitrile is a highly efficient synergist for the aggregation pheromone components of Ips typographus, and its synergistic effect is concentration-dependent. The attractive biological activity is more obvious at the dose of 20 mg of (S)-(–)-ipsenol, 20 mg of (S)-(+)-ipsdienol, and 4000 mg of phenylacetonitrile.

[0041] In addition, only Ips typographus was trapped in the traps of Treatments 3 - 6 in this example, indicating that phenylacetonitrile does not affect the specificity of the attractant for Ips typographus, and it also proves that this attractant core has very strong specificity.

[0042] Example 2. Evaluation of the synergistic effect of phenylacetonitrile on aggregation pheromone cores with different dosages for Ips typographus

[0043] Prepare the following 5 treatments according to the test requirements:

[0044] Treatment 1: Blank treatment, the attractant core is only sterile absorbent cotton;

[0045] Treatment 2: Add 20 mg of 97% (S)-(–)-ipsenol and 20 mg of 97% (S)-(+)-ipsdienol to the attractant core carrier;

[0046] Treatment 3: Add 40 mg of 97% (S)-(–)-ipsenol and 40 mg of 97% (S)-(+)-ipsdienol to the attractant core carrier;

[0047] Treatment 4: Add 20 mg of 97% (S)-(–)-ipsenol, 20 mg of 97% (S)-(+)-ipsdienol, and 4000 mg of phenylacetonitrile to the attractant core carrier;

[0048] Treatment 5: Add 40 mg of 97% (S)-(–)-ipsenol, 40 mg of 97% (S)-(+)-ipsdienol, and 4000 mg of phenylacetonitrile to the lure carrier;

[0049] (1) Prepare lures with different ratios by mixing 97% (S)-(–)-ipsenol, 97% (S)-(+)-ipsdienol, and phenylacetonitrile according to the above ratios.

[0050] (2) Preparation and storage of lure cores: Add the lure to 3 g of sterile absorbent cotton, and then place it in a 20-mil black polyethylene plastic bag. The prepared lure cores are sealed with aluminum foil and refrigerated at 4°C.

[0051] (3) Field application of lure cores:

[0052] a) Experiment time and location: From July 15th to August 15th, 2020, at Saihanba Mechanical Forest Farm, Chengde City, Hebei Province.

[0053] b) Fabrication of traps: The trap is mainly a funnel-shaped ips beetle trap, purchased from Beijing Zhongjie Sifang Biotechnology Co., Ltd. The bottom of the funnel trap is connected to a collection bottle.

[0054] c) Suspension of lure cores: Suspend 1 lure core at the middle position from the top of the funnel-shaped ips beetle trap.

[0055] d) Field setting of traps: Set 3 replicates for each experimental treatment. The traps are set at the edge of the larch forest, and the distance between traps is approximately 30 m. Insert two 2-m long bamboo poles with a diameter of 5 cm into the soil about 50 cm deep, with a distance of 30 cm between the two bamboo poles, and then fix the trap between the two bamboo poles. The collection bottle of the trap is 50 cm above the ground.

[0056] e) Data investigation and emptying of traps: Set 3 replicates for each treatment in this experiment. The average number of Ips typographus trapped in each treatment is the average of 3 traps. According to the weather conditions, observe the number of ips beetles in the collection bottle every 2 - 3 days. After counting, take the trapped Ips typographus to the laboratory in a plastic box.

[0057] From the analysis of the trapping effect (such as Figure 2As can be seen from the figure (not shown), Treatment 1 (blank treatment) could not attract Ips typographus; Treatment 2 (20 mg of 97% (S)-(–)-ipsenol and 20 mg of 97% (S)-(+)-ipsdienol) had a good trapping effect. When both (S)-(–)-ipsenol and (S)-(+)-ipsdienol were increased to 40 mg (Treatment 3), the trapping effect on Ips typographus increased by 4 times, and the average number of trapped insects reached 159. The average number of trapped Ips typographus by the Ips typographus attractant prepared with 20 mg of 97% (S)-(–)-ipsenol, 20 mg of 97% (S)-(+)-ipsdienol and 4000 mg of phenylacetonitrile (Treatment 4) was 219, which was significantly higher than that of Treatment 2 and Treatment 3, and there was little difference in the trapping amount from Treatment 5 (40 mg of 97% (S)-(–)-ipsenol, 40 mg of 97% (S)-(+)-ipsdienol, 4000 mg of phenylacetonitrile). This shows that phenylacetonitrile as a synergist can reduce the usage amount of the aggregation pheromone components of Ips typographus, has an obvious synergistic effect, the addition of phenylacetonitrile can reduce the production cost of the Ips typographus attractant, and can also achieve a good prevention and control effect.

[0058] Secondly, the species of bark beetles in the traps of Treatments 2 - 5 in this example were all Ips typographus, indicating that this lure core has very strong specificity.

[0059] Example 3. Evaluation of the long-term synergistic effect of phenylacetonitrile on the Ips typographus attractant

[0060] Prepare the following 3 treatments according to the test requirements:

[0061] Treatment 1: Blank treatment, the lure core is only sterile absorbent cotton;

[0062] Treatment 2: Add 20 mg of 97% (S)-(–)-ipsenol and 20 mg of 97% (S)-(+)-ipsdienol to the lure core carrier;

[0063] Treatment 3: Add 20 mg of 97% (S)-(–)-ipsenol, 20 mg of 97% (S)-(+)-ipsdienol and 4000 mg of phenylacetonitrile to the lure core carrier.

[0064] (1) Prepare attractants with different ratios by mixing 97% (S)-(–)-ipsenol, 97% (S)-(+)-ipsdienol and phenylacetonitrile according to the above ratios.

[0065] (2) Preparation and storage of the lure core: Add the attractant to 3 g of sterile absorbent cotton, and then place it in a 20-mesh black polyethylene plastic bag. The prepared lure core is sealed with aluminum foil paper and refrigerated at 4°C.

[0066] (3) Field application of the lure core:

[0067] a) Experiment time and location: From June 5th to August 20th, 2021, at Saihanba Mechanical Forest Farm, Chengde City, Hebei Province.

[0068] b) Fabrication of the trap: The trap is mainly a funnel-shaped bark beetle trap, purchased from Beijing Zhongjie Sifang Biotechnology Co., Ltd. The bottom of the funnel trap is connected to the insect collection bottle.

[0069] c) Suspension of the lure core: Hang 1 lure core at the middle position from the top of the funnel-shaped bark beetle trap.

[0070] d) Field setting of the trap: Set 3 replicates for each experimental treatment. The traps are set at the edge of the larch forest, and the distance between the traps is approximately 30 m. Insert two bamboo poles with a length of 2 m and a diameter of 5 cm into the soil layer about 50 cm deep, with a distance of 30 cm between the two bamboo poles. Then fix the trap between the two bamboo poles, and the insect collection bottle of the trap is 50 cm above the ground.

[0071] e) Data investigation and emptying of the trap: Set 3 replicates for each treatment in this experiment. The average number of Ips subelongatus captured in each treatment is the average of the numbers captured by 3 traps. According to the weather conditions, observe the number of Ips subelongatus in the insect collection bottle every 6 - 7 days. After counting, put the captured bark beetles into a plastic box and take them to the laboratory.

[0072] From the analysis of the insect trapping effect (such as Figure 3As can be seen from the figure (not shown), Treatment 2 had a good trapping effect throughout the investigation period, indicating that the lure core of the Ips typographus attractant composed of 20 mg of 97% (S)-(–)-ipsenol and 20 mg of 97% (S)-(+)-ipsdienol had a good long-lasting period. The trapping effect of Treatment 3 on Ips typographus was better than that of Treatment 2. In the early stage of the investigation (early June), since the flight period of Ips typographus in the forest had just begun, the number of trapped insects was small. Although phenylacetonitrile had a certain synergistic effect on the lure core of the Ips typographus aggregation pheromone, there was no obvious difference from the control group (Treatment 2). As the flight period of Ips typographus advanced, especially when it entered the peak flight period, phenylacetonitrile showed a very good synergistic effect on the attraction of Ips typographus, and the trapping amount increased by 2 - 6 times, and the synergistic long-lasting period reached more than 50 days. This experiment shows that the Ips typographus attractant prepared with 97% (S)-(–)-ipsenol, 97% (S)-(+)-ipsdienol and phenylacetonitrile can significantly increase the trapping amount of Ips typographus, and its synergistic attraction to the Ips typographus aggregation pheromone is long-term, indicating that phenylacetonitrile can be used as a good synergistic attractant in the trapping and control of Ips typographus, and the long-term trapping data can also accurately show the population dynamics during the flight period of Ips typographus.

[0073] In addition, during the entire trapping period, only Ips typographus was trapped in the traps of Treatments 2 - 3 in this example, indicating that this lure core has very strong specificity.

[0074] Example 4. Comparison of the influence of phenylacetonitrile and other plant-derived synergistic agents on the attraction effect of the Ips typographus aggregation pheromone lure core

[0075] Prepare the following 5 treatments according to the test requirements:

[0076] Treatment 1: Blank treatment, the lure core is only sterile absorbent cotton;

[0077] Treatment 2: Add 20 mg of 97% (S)-(–)-ipsenol and 20 mg of 97% (S)-(+)-ipsdienol to the lure core carrier;

[0078] Treatment 3: Add 20 mg of 97% (S)-(–)-ipsenol, 20 mg of 97% (S)-(+)-ipsdienol and 4000 mg of (S)-β-pinene to the lure core carrier;

[0079] Treatment 4: Add 20 mg of 97% (S)-(–)-ipsenol, 20 mg of 97% (S)-(+)-ipsdienol and 4000 mg of myrcene to the lure core carrier;

[0080] Treatment 5: Add 20 mg of 97% (S)-(–)-ipsenol, 20 mg of 97% (S)-(+)-ipsdienol, and 4000 mg of phenylacetonitrile to the lure core.

[0081] (1) Prepare attractants with different ratios by formulating 97% (S)-(–)-ipsenol, 97% (S)-(+)-ipsdienol, phenylacetonitrile, myrcene, or (S)-β-pinene according to the above ratios.

[0082] (2) Preparation and storage of lure cores: Add the attractant to 3 g of sterile absorbent cotton, and then place it in a 20-mil black polyethylene plastic bag. The prepared lure cores are sealed with aluminum foil and refrigerated at 4°C.

[0083] (3) Field application of lure cores:

[0084] a) Experiment time and location: From June 25 to July 25, 2022, in Saihanba Mechanical Forest Farm, Chengde City, Hebei Province.

[0085] b) Fabrication of traps: The trap is mainly a funnel-shaped ips beetle trap, purchased from Beijing ZhongJieSiFang Biotechnology Co., Ltd. The bottom of the funnel trap is connected to a collection bottle.

[0086] c) Suspension of lure cores: Suspend 1 lure core at the middle position from the top of the funnel-shaped ips beetle trap.

[0087] d) Field setting of traps: Set 3 replicates for each experimental treatment. The traps are set at the edge of the larch forest, and the distance between traps is about 30 m. Insert two 2-m long bamboo poles with a diameter of 5 cm into the soil about 50 cm deep, with a distance of 30 cm between the two bamboo poles, and then fix the trap between the two bamboo poles. The collection bottle of the trap is 50 cm above the ground.

[0088] e) Data investigation and emptying of traps: Set 3 replicates for each treatment in this experiment. The average number of Ips typographus captured in 3 traps is taken for each treatment. According to the weather conditions, observe the number of Ips typographus in the collection bottle every 7 days. After counting, put the captured Ips typographus into a plastic box and take it to the laboratory.

[0089] From the analysis of the trapping effect (as Figure 4 shown), it can be seen that Treatment 2 and after adding myrcene (Treatment 4), (S)-β-pinene (Treatment 3), or phenylacetonitrile (Treatment 5) all have good trapping effects. From the perspective of the trapping quantity, adding phenylacetonitrile has the best attracting effect on Ips typographus, followed by myrcene and (S)-β-pinene respectively.

[0090] This experiment shows that the larch bark beetle attractant formulated with 97% (S)-(–)-ipsenol, 97% (S)-(+)-ipsdienol, and benzonitrile can significantly increase the trapping amount of the larch bark beetle. Moreover, benzonitrile has a better attracting effect on the larch bark beetle compared to the two volatiles, myrcene and (S)-β-pinene, indicating that benzonitrile can be used as an excellent attracting synergist in the trapping and control of the larch bark beetle.

[0091] Example 5. Influence of Benzonitrile on the Attracting Effect of the Aggregation Pheromone Lure Core of the Larch Bark Beetle at Different Locations

[0092] Prepare the following 3 treatments according to the test requirements:

[0093] Treatment 1: Blank treatment, the lure core is only sterile absorbent cotton.

[0094] Treatment 2: 20 mg of 97% (S)-(–)-ipsenol and 20 mg of 97% (S)-(+)-ipsdienol.

[0095] Treatment 3: 20 mg of 97% (S)-(–)-ipsenol, 20 mg of 97% (S)-(+)-ipsdienol, and 4000 mg of benzonitrile.

[0096] (1) Prepare the attractants with different ratios by formulating 97% (S)-(–)-ipsenol, 97% (S)-(+)-ipsdienol, and benzonitrile according to the above ratios.

[0097] (2) Preparation and preservation of the lure core: Add the attractant to 3 g of sterile absorbent cotton, and then place it in a 20 s black polyethylene plastic bag. The prepared lure core is sealed with aluminum foil and refrigerated at 4°C.

[0098] (3) Field application of the lure core:

[0099] a) Experiment time and location: Saihanba Mechanical Forest Farm, Chengde City, Hebei Province (July 16 - August 15, 2023), Mengjiagang Forest Farm, Huanan County, Jiamusi City, Heilongjiang Province (July 5 - August 5, 2023), Dajizi Forest Farm, Keshiketeng Banner, Inner Mongolia (July 15 - August 15, 2023);

[0100] b) Manufacture of the trap: The trap is mainly a funnel-shaped bark beetle trap, purchased from Beijing Zhongjie Sifang Biotechnology Co., Ltd. The bottom of the funnel trap is connected to the insect collection bottle.

[0101] c) Suspension of the lure core: Suspend 1 lure core at the middle position from the top of the funnel-shaped bark beetle trap.

[0102] d) Field setting of the trap: For each experimental treatment at the above 3 experimental sites, 3 replicates were set. The traps were set at the edge of the larch forest, and the distance between the traps was approximately 30 m. Insert two bamboo poles with a length of 2 m and a diameter of 5 cm into the soil layer about 50 cm deep, with a distance of 30 cm between the two bamboo poles. Then fix the trap between the two bamboo poles, and the insect collection bottle of the trap was 50 cm above the ground.

[0103] e) Data investigation and emptying of the trap: For this experiment, 3 replicates were set for each treatment, and the average number of Ips typographus trapped in each treatment was the average of 3 traps. According to the weather conditions, the number of Ips typographus in the insect collection bottle was observed once every 7 days. After counting, the trapped Ips typographus were put into a plastic box and taken to the laboratory.

[0104] From the analysis of the trapping effect (as Figure 5 shown), it can be seen that the synergistic effect of phenylacetonitrile on the aggregation pheromone lure core of Ips typographus is stable in 3 places, namely Saihanba Mechanical Forest Farm in Chengde City, Hebei Province, Mengjiagang Forest Farm in Huanan County, Jiamusi City, Heilongjiang Province, and Dajuziliang Forest Farm in Keshiketeng Banner, Inner Mongolia, and the synergy can reach 3 - 5 times. This experiment shows that the Ips typographus attractant prepared with 97% (S)-(–)-ipsenol, 97% (S)-(+)-ipsdienol and phenylacetonitrile can significantly increase the trapping amount of Ips typographus at different locations, indicating that the synergistic effect of phenylacetonitrile on the aggregation pheromone lure core of Ips typographus is relatively stable.

[0105] Secondly, only Ips typographus was trapped in the trap of this embodiment, indicating that this lure core has very strong specificity.

[0106] In summary, the Ips typographus lure core provided by the present invention is easy to process and produce, with low cost, and the release of the 3 components on the slow-release bag is stable, and the effective period is more than 50 days, which can meet the need for a large number of trapping and prevention and control of Ips typographus during the flying period. The lure core provided by the present invention is an efficient, long-lasting and environment-friendly Ips typographus lure core, which can significantly increase the trapping number of Ips typographus, can realize the large-scale trapping and prevention and control of Ips typographus, and has remarkable results, with broad industrialization prospects and is suitable for large-scale popularization and application in production.

[0107] 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. Use of phenylacetonitrile as a synergist for Ips typographus attractant, wherein the Ips typographus attractant comprises (S)-(–)-ipsenol and (S)-(+)-ipsdienol.

2. The use according to claim 1, characterized in that the mass ratio of phenylacetonitrile to (S)-(–)-ipsenol and (S)-(+)-ipsdienol is 0.04 - 4:0.02 - 0.04:0.02 - 0.

04.

3. An Ips typographus attractant, characterized in that it comprises the following components in parts by weight: 0.02 - 0.04 parts of 97% (S)-(–)-ipsenol, 0.02 - 0.04 parts of 97% (S)-(+)-ipsdienol, and 0.04 - 4 parts of phenylacetonitrile.

4. The Ips typographus attractant according to claim 3, characterized in that it comprises the following components in parts by weight: 0.02 parts of 97% (S)-(–)-ipsenol, 0.02 parts of 97% (S)-(+)-ipsdienol, and 4 parts of phenylacetonitrile.

5. A lure core for attracting Ips typographus, characterized in that the attractant described in claim 3 or 4 is provided in the lure core.

6. The lure core according to claim 5, characterized in that it comprises one or both of the following (1) - (2): (1) The dosage of 97% (S)-(–)-ipsenol in a single lure core is 20 mg; the dosage of 97% (S)-(+)-ipsdienol is 20 mg; the dosage of phenylacetonitrile is 4000 mg; (2) The lure core further comprises a slow - release carrier, the slow - release carrier is a polyethylene plastic bag; a degreased cotton is arranged inside the slow - release carrier, and the attractant is adsorbed on the degreased cotton.

7. The lure core according to claim 6, characterized in that the dosage of degreased cotton in a single lure core is 3 g; and / or, the thickness of the polyethylene plastic bag is 20 silk, the length is 150 mm, and the width is 70 mm.

8. A preparation method of the lure core according to claim 7, characterized in that it comprises the following steps: Placing the degreased cotton in a polyethylene plastic bag, then dropping the attractant on the degreased cotton, and sealing to obtain the lure core.

9. Application of the lure core according to any one of claims 5 - 7 in trapping Ips typographus.

10. The application according to claim 9, characterized in that the application comprises: hanging the lure core in the forest, and the number of lures hung per mu is 2 - 3.

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