Attractant for millettia migo in foxtail millet and use method of attractant

Abstract

The invention belongs to the technical field of agricultural planting, and particularly relates to an attractant for millettia migo in foxtail millet and a using method thereof.The attractant is prepared from, by mass, 5-10 parts of foxtail millet leaf extract, 30-40 parts of n-hexane, 1-2 parts of dispersing agent and 1-2 parts of amylodextrin; the foxtail millet leaf extract is prepared from 2-ethyl hexanol, nonanal, 1-octylene-3-ol, myrcene, tridecane, tetradecane and eudesmol. According to the attractant, the foxtail millet leaf extract is used as a main material, and other alcohol, aldehyde and alkene additives are used as auxiliary materials, so that substances with an attraction effect on the foxtail millet can be volatilized and diffused, the attraction force of the attractant on the foxtail millet is far greater than that of foxtail millet seedlings, and the foxtail millet seedlings are prevented from being damaged by the foxtail millet seedlings.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural planting, and particularly relates to an attractant for millet mudworm in millet and a use method thereof. Background Art

[0002] Oulema tristis Herbst, also known as millet leaf beetle, belongs to the family Oulema of the order Coleoptera. It is distributed in Heilongjiang, Jilin, Liaoning, Inner Mongolia, Ningxia, Gansu, Shaanxi, Shanxi, Hebei, Henan, Beijing and other regions in my country. The insect mainly harms millet, but can also harm sorghum, broomcorn millet and various weeds of the Gramineae family. The larvae are the main cause of damage. The larvae often hide in the heart leaves and lick the mesophyll, causing wide white stripe-like food marks. In severe cases, it can cause heart dryness, rotten seedlings or the whole plant to die. Adults can also cause certain damage, feeding on the mesophyll along the veins, leaving only the epidermis, forming long white stripes, and in severe cases, the leaves are broken and filamentous.

[0003] In recent years, the implementation of farming systems such as returning straw to the fields and no-till sowing has provided convenient conditions for the overwintering of millet mudworms. In the areas where the disease has occurred, there are 300 to 600 insects per 100 plants, more than 20 insects per single plant, and the rate of damaged plants is over 90%. It has become the main pest on millet and poses a serious threat to the yield and quality of millet.

[0004] Because the larvae of millet mudworms hide in the heart leaves of millet, their symptoms are not obvious and it is difficult to attract people's attention. When millet enters the jointing stage, white scorched leaves appear in large numbers, and the best prevention and control period has been missed. In production, the main focus is on preventing and controlling overwintering adults, but adults have a long survival time and can gradually migrate into millet fields, making it difficult to spray chemical pesticides for prevention and control. In addition, excessive use of chemical pesticides will bring about a series of negative impacts such as ecological environmental safety, food safety, and pest resistance. Therefore, it is very necessary to develop green prevention and control technologies that are conducive to sustainable development. Summary of the invention

[0005] In order to solve the problems existing in the above-mentioned prior art, the present invention provides an attractant for millet mudworm in millet and a use method thereof. By using millet leaf extract as the main ingredient and other alcohol, aldehyde and olefin additives as the auxiliary ingredients, the substances in the leaves that have an attractant effect on millet mudworm can be volatilized and diffused, so that the attractant has a much greater attraction to millet mudworm than the millet seedlings, thereby preventing the millet mudworm from harming the millet seedlings.

[0006] The specific technical solution adopted by the present invention is:

[0007] An attractant for millet mudworm in millet, comprising the following components by weight: 5-10 parts of millet leaf extract, 30-40 parts of n-hexane, 1-2 parts of dispersant and 1-2 parts of starch dextrin;

[0008] The foxtail millet leaf extract includes 2-ethylhexanol, nonanal, 1-octen-3-ol, myrcene, tridecane, tetradecane and eucalyptol.

[0009] Furthermore, an attractant for millet mud moth in millet includes the following components, measured by mass: 5-10 parts of millet leaf extract, 0.5-1.5 parts of trans-2-hexenal, 1-1.5 parts of citral, 0.5-1 parts of ocimene, 30-40 parts of n-hexane, 1-2 parts of dispersant and 1-2 parts of starch dextrin.

[0010] The method for obtaining millet leaf extract comprises the following steps:

[0011] A1. Place millet seedling leaves in a flange reactor and seal it with a sealing film. Connect the lower end of the reactor to activated carbon, and the upper end to the air inlet pipe and adsorbent tube. After connecting the atmospheric sampler, use a flow meter to check the air tightness of the device.

[0012] A2, flange reactor pre-evacuated for 30-40 minutes, connected to adsorption column, collected for 18-24 hours;

[0013] A3. After the collection is completed, the volatile substances collected in the adsorption column are eluted with n-hexane, which is the millet leaf extract.

[0014] The air flow rate of the atmospheric sampler described in step A1 is 500 mL / min.

[0015] The preparation method of the attractant comprises the following steps:

[0016] B1. First, add the millet leaf extract to 20-25 parts of n-hexane and stir evenly to obtain an attractant base solution;

[0017] B2, adding trans-2-hexenal, citral and ocimene to the remaining n-hexane, and then adding a dispersant and stirring evenly to obtain an auxiliary liquid;

[0018] B3. Mix the attractant base liquid and the auxiliary liquid, add the dispersant and stir evenly, then add starch dextrin in batches and stir evenly to obtain the attractant.

[0019] The method of using the attractant specifically includes the following steps:

[0020] S1, adding the attractant into the slow-release carrier, and then sealing it to make the attractant core;

[0021] S2. Place the lure core on the trap and hang it in the rice field.

[0022] Furthermore, the sustained-release carrier is a polyethylene bottle.

[0023] Furthermore, the traps are arranged in a rectangular array in the valley field, with a density of 80-120 m 2 Set up a set of traps.

[0024] The beneficial effects of the present invention are:

[0025] 1. The present invention studies the ingredients of millet leaves, screens out volatile ingredients with attractant activity to millet mudworms, and develops an attractant. The attractant ingredients are derived from plant leaves, are non-toxic and have no residue, and will not cause environmental pollution. At the same time, the attractant can kill adult insects and reduce the population of their offspring. It has important prevention and control value and is an ideal green prevention and control technology.

[0026] 2. In the present invention, millet leaf extract is used as the main ingredient and other alcohol, aldehyde and olefin additives are used as the auxiliary ingredients. The substances in the leaves that have an attractant effect on millet mudworms can be volatilized and diffused, so that the attractant has a much greater attraction to millet mudworms than millet. The attractant is used to lure millet mudworms and capture them, thereby preventing millet mudworms from feeding and damaging millet.

[0027] 3. In the present invention, n-hexane is used as a solvent and a dispersant is added, so that the active substances in the components can be better dissolved. At the same time, n-hexane itself has good volatility, which further improves the attractant's attracting effect on millet mudworms. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The EAG responses of male and female adults of O. chinensis to different doses of seven volatiles;

[0029] Figure 2 The behavioral responses of female adults of O. chinensis to seven volatile standard substances with different mass concentrations;

[0030] Figure 3 The behavioral responses of male adults of O. millet to seven volatile standard substances with different mass concentrations. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. 1. Specific embodiments

[0033] 1. Extraction of millet leaf extract

[0034] The following steps are involved:

[0035] A1. Place millet seedling leaves in a flange reactor and seal it with a sealing film. Connect the lower end of the reactor to activated carbon, and the upper end to the air inlet pipe and adsorbent tube. After connecting the atmospheric sampler, use a flow meter to check the air tightness of the device.

[0036] The air flow rate of the atmospheric sampler is 500mL / min;

[0037] A2, flange reactor pre-evacuated for 30 minutes and then connected to adsorption column, collecting from 8 am to 8 am the next day, for 24 hours;

[0038] A3. After the collection is completed, the volatile substances collected in the adsorption column are eluted with 1 mL of chromatographically pure n-hexane, which is the millet leaf extract.

[0039] 2. Preparation of attractants

[0040] Example 1

[0041] B1. First, add 8 parts of leaf extract to 25 parts of n-hexane and stir evenly to obtain an attractant base solution;

[0042] B2. Add 2 parts of dispersant into the attractant base liquid and stir evenly, then add 1.5 parts of starch dextrin in batches and stir evenly to obtain the attractant.

[0043] Example 2

[0044] B1. First, add 5 parts of leaf extract to 20 parts of n-hexane and stir evenly to obtain an attractant base solution;

[0045] B2. Add 1 part of dispersant into the attractant base liquid and stir evenly, then add 1 part of starch dextrin in batches and stir evenly to obtain the attractant.

[0046] Example 3

[0047] B1. First, add 10 parts of leaf extract to 30 parts of n-hexane and stir evenly to obtain an attractant base solution;

[0048] B2, adding 1.5 parts of trans-2-hexenal, 1.5 parts of citral and 1 part of ocimene to 10 parts of n-hexane, stirring evenly to obtain an auxiliary liquid;

[0049] B3. Mix the attractant base liquid and the auxiliary liquid and add 2 parts of dispersant and stir evenly. Then add 2 parts of starch dextrin in batches and stir evenly to obtain the attractant.

[0050] Example 4

[0051] B1. First, add 6 parts of leaf extract to 15 parts of n-hexane and stir evenly to obtain an attractant base solution;

[0052] B2, adding 1.2 parts of trans-2-hexenal, 1.5 parts of citral and 0.6 parts of ocimene to 15 parts of n-hexane, stirring evenly to obtain an auxiliary liquid;

[0053] B3. Mix the attractant base liquid and the auxiliary liquid and add 1.5 parts of dispersant and stir evenly. Then add 1 part of starch dextrin in batches and stir evenly to obtain the attractant.

[0054] Example 5

[0055] B1. First, add 8 parts of leaf extract to 25 parts of n-hexane and stir evenly to obtain an attractant base solution;

[0056] B2, adding 1 part of trans-2-hexenal, 1.2 parts of citral and 0.8 parts of ocimene to 10 parts of n-hexane, stirring evenly to obtain an auxiliary liquid;

[0057] B3. Mix the attractant base liquid and the auxiliary liquid and add 2 parts of dispersant and stir evenly. Then add 1.5 parts of starch dextrin in batches and stir evenly to obtain the attractant.

[0058] Comparative Example 1

[0059] The difference between Comparative Example 1 and Example 3 is that Comparative Example 1 does not contain millet leaf extract, and the specific steps are as follows:

[0060] B1, add 1.5 parts of trans-2-hexenal, 1.5 parts of citral and 1 part of ocimene to 20 parts of n-hexane, stir evenly to obtain an attractant base liquid;

[0061] B3. Add 1 part of dispersant into the attractant base liquid and stir evenly, then add 1 part of starch dextrin in batches and stir evenly to obtain the attractant.

[0062] 2. Performance Test

[0063] 1. Identification of millet volatile components:

[0064] The collection of volatiles adopts the "dynamic headspace collection method". When collecting, first wrap the roots of the plants with aluminum foil, tilt the lower half of the flange reactor cover appropriately, gently put the plants along the cover, cover the upper half of the reactor cover, and seal it with a sealing film. The lower end of the reactor is connected to activated carbon, and the upper end of the reactor is connected to the air inlet pipe and the adsorbent tube. When pumping, the air flow rate of the atmospheric sampler is 500mL / min, and the air tightness of the device is checked with a flow meter. The silicone tubes used to connect the entire device are all Teflon hoses without volatile gases. In order to avoid the generation of miscellaneous odors in the entire device, connect the collection system, pre-pump for 30 minutes, and then connect the adsorption column. The collection time for all plants is set to 24h. After the collection is completed, the adsorption column is immediately removed, and the plant volatile substances collected in the adsorption column are eluted into the injection bottle with 1mL of chromatographic pure hexane, and stored at -20℃ for use. At the same time, collect air (empty flange reactor without plants) for 24h as a blank control.

[0065] The millet volatile samples collected by dynamic headspace were analyzed by GC-MS, and 18 compound components were identified by searching the NIST14 spectral library and combining the standard mass spectrum and retention time. The percentage content of each component was calculated by peak area normalization method. The analysis results are shown in Table 1. The types of millet volatiles mainly include aldehydes, alkenes, alcohols and alkanes, and the relative content of alcohols and alkenes is the highest, accounting for more than 85%, which is significantly higher than other types of compounds.

[0066] Table 1

[0067] Serial number Compound Retention time (minutes) Relative content (%) 1 Decane 3.494 0.50 2 α-Pinene 3.785 2.13 3 Undecane 4.769 0.06 4 1,3,5-Octatriene 4.955 14.72 4 β-Pheretene 5.345 0.47 6 β-Myrcene 6.156 0.94 7 Limonene 6.902 2.53 8 Dodecane 7.015 0.87 9 Eucalyptol 7.179 3.85 10 Styrene 8.142 1.19 11 Tridecane 9.356 5.89 12 Nonanal 11.497 0.83 13 Tetradecane 11.801 6.17 14 1-Octen-3-ol 12.950 10.15 15 2-Ethylhexanol 13.910 17.33 16 β-elemene 16.426 24.51 17 β-cubane 19.362 6.16 18 β-cadinene 20.240 1.69

[0068] 2. Electroantennary Potential Experiment:

[0069] Each volatile standard compound was diluted with n-hexane to prepare 5 series of concentrations (100, 10, 1, 0.1 and 0.01 μg / mL), with n-hexane as the blank control. The entire antennae of active male and female adults of the millet mudworm were cut off from the base, the ends were cut off, and the two ends of the antennae were connected to the electrodes coated with conductive glue with insect pins, and the electrophysiological activity test was carried out after the baseline was stable.

[0070] Take 10 μL of the sample solution to be tested and evenly apply it on a filter paper strip (5.0 cm × 0.5 cm). After the solvent evaporates, put it into a Pasteur tube, and then connect the Pasteur tube to the stimulating airflow. Adjust the continuous airflow flow to 500 mL / min, the stimulating airflow to 40 mL / min, the stimulation time to 0.1 s each time, and the interval between 2 stimulations to 30 s to restore the sensitivity of the antennae. Test 5 antennae of each male and female adult of each sample. Use n-hexane as the control, and test the control once before and after the test sample. During the test, the ambient temperature was 25°C ± 1°C, and the humidity was 60% to 70%. See the test results. Figure 1 , wherein the volatiles used in Figures AG are A: 2-ethylhexanol; B: nonanal; C: 1-octen-3-ol; D: myrcene; E: tridecane; F: tetradecane; and G: eucalyptol.

[0071] The results showed that male and female adults of the millet mudworm had no obvious EAG reaction to the three volatiles of tridecane, tetradecane and eucalyptol, and the EAG reaction value remained basically unchanged with the increase of the concentration of the volatiles. Male and female adults of the millet mudworm produced strong EAG reactions to the four volatiles of 2-ethylhexanol, nonanal, 1-octen-3-ol and myrcene, and the EAG reaction increased with the increase of the concentration of the volatiles. There was basically no EAG reaction at a low concentration, and a strong EAG reaction was produced at the maximum test concentration of 100μL / mL. Among them, the female adults of the millet mudworm reacted more strongly to nonanal and 1-octen-3-ol than to 2-ethylhexanol and myrcene.

[0072] 3. The tropism behavior of the millet mudworm to seven volatile substances:

[0073] The Y-type olfactometer was used to measure the directional behavioral responses of male and female adults of S. millet to seven plant volatiles. The Y-type olfactometer was made of colorless transparent glass with an inner diameter of 3 cm. The straight tube at the base was 25 cm long, the two arms were 20 cm long, and the angle between the two arms was 75°. Before the test, the Y-type tube was connected to the odor source with an equal length silicone tube. The QC-1B atmospheric sampler was used as the airflow power system. The odor source was connected to a vacuum pump. Before the airflow entered the odor source, it first passed through an activated carbon filter device and a distilled water washing bottle to purify the airflow and increase the humidity of the airflow. The gas flow rate was controlled at 200 mL / min. 20 μL of volatile solution was taken as the odor source, and filter paper strips with volatiles were placed on both sides of the Y-type tube. The atmospheric sampler was turned on and ventilated for 10 minutes to allow the odor to fill the entire device. Then a single head of S. millet adult was introduced into the olfactometer using a centrifuge tube, and the behavioral response of the insect was observed within 10 minutes.

[0074] The evaluation criteria are as follows: if the insect flies to more than 1 / 2 of a side arm and stays for more than 30 seconds or flies directly to the end of the arm, it is recorded as a reaction to the volatiles. If within 10 minutes, the insect only wanders in the straight tube or moves quickly between the two arms, it is considered to have no obvious preference for the volatiles and is recorded as no reaction. 50 female and male adults of millet mudworms were tested for each odor source combination. Each adult was tested only once. After testing 5 test insects, the two arms of the "Y" type olfactometer were swapped. After measuring 10 test insects, the "Y" type olfactometer was cleaned with acetone and dried.

[0075] Figure 2 The results show that the female adults of the millet mudworm responded to seven different concentrations of volatile standard substances. The results show that 0.01, 0.1, 1, 10, 100 μg / mL of 2-ethylhexanol, nonanal, 1-octen-3-ol and myrcene all had extremely significant attractant effects (P<0.01). Eucalyptol had extremely significant attractant effects at concentrations of 10 and 100 μg / mL (P<0.01). Tetradecane had significant attractant effects on the insect at concentrations of 10 and 100 μg / mL (P<0.05). Tridecane had significant attractant effects on the insect only at a concentration of 100 μg / mL (P<0.05).

[0076] Figure 3The results show the behavioral responses of male adults of the millet mudworm to seven different concentrations of volatile standards. The results show that myrcene has a very significant attraction to male adults at 5 concentrations of 0.01, 0.1, 1, 10, and 100 μg / mL (P<0.01). 1-Octene-3-ol has a very significant attraction to male adults at 4 concentrations of 0.1, 1, 10, and 100 μg / mL (P<0.01). 2-Ethylhexanol and nonanal have a very significant attraction to male adults at 3 concentrations of 1, 10, and 100 μg / mL (P<0.01). Eucalyptol has a very significant attraction at 10 and 100 μg / mL (P<0.01). Tridecane and tetradecane have a significant attraction to the insect only at a concentration of 100 μg / mL (P<0.05).

[0077] 4. Tests of Examples and Comparative Examples

[0078] The attractants prepared in Examples 1-5 and Comparative Example 1 were made into lure cores and placed in traps, and the rice field was divided into regions 1-7. Then, the trap prepared in Example 1 was placed in region 1, and the trap prepared in Example 2 was placed in region 2, and so on. Region 7 was used as a blank control group, and no trap was placed.

[0079] Field management was carried out in areas 1-7 with the same management parameters such as irrigation and fertilization. No pesticides were sprayed or artificial insect trapping was performed during the period. The growth of millet and the number of millet mudworms caught by traps were counted every 7 days. Table 2 shows the growth of millet, and Table 3 shows the number of millet mudworms caught.

[0080] Table 2

[0081]

[0082] Table 3

[0083]

[0084] It can be seen from Table 2 and Table 3 that the attractants prepared in Examples 3-5 have a greater attracting effect on millet mudworms. This is because the combination of trans-2-hexenal, citral and ocimene increases the volatilization effect of millet leaf volatiles, thereby improving the attracting effect on millet mudworms.

Claims

1. An attractant for millet mudworm in millet, characterized in that: The invention comprises the following components by weight: 5-10 parts of millet leaf extract, 30-40 parts of n-hexane, 1-2 parts of dispersant and 1-2 parts of starch dextrin; The foxtail millet leaf extract includes 2-ethylhexanol, nonanal, 1-octen-3-ol, myrcene, tridecane, tetradecane and eucalyptol.

2. The attractant for Ophiopogon fusiformis in millet according to claim 2, characterized in that: The invention comprises the following components by weight: 5-10 parts of millet leaf extract, 0.5-1.5 parts of trans-2-hexenal, 1-1.5 parts of citral, 0.5-1 parts of ocimene, 30-40 parts of normal hexane, 1-2 parts of dispersant and 1-2 parts of starch dextrin.

3. The attractant for Ophiocordyceps sinensis in millet according to claim 1, characterized in that: The method for obtaining the millet leaf extract comprises the following steps: A1. Place millet seedling leaves in a flange reactor and seal it with a sealing film. Connect the lower end of the reactor to activated carbon, and the upper end to the air inlet pipe and adsorbent tube. After connecting the atmospheric sampler, use a flow meter to check the air tightness of the device. A2, flange reactor pre-evacuated for 30-40 minutes, connected to adsorption column, collected for 18-24 hours; A3. After the collection is completed, the volatile substances collected in the adsorption column are eluted with n-hexane, which is the millet leaf extract.

4. The attractant for Ophiocordyceps sinensis in millet according to claim 3, characterized in that: The air flow rate of the atmospheric sampler described in step A1 is 500 mL / min.

5. A method for preparing an attractant for Ophiocordyceps sinensis in millet according to claim 2, characterized in that: The preparation method of the attractant comprises the following steps: B1. First, add the millet leaf extract to 20-25 parts of n-hexane and stir evenly to obtain an attractant base solution; B2, adding trans-2-hexenal, citral and ocimene to the remaining n-hexane, stirring evenly to obtain an auxiliary liquid; B3. Mix the attractant base liquid and the auxiliary liquid, add the dispersant and stir evenly, then add starch dextrin in batches and stir evenly to obtain the attractant.

6. A method for using the attractant for millet mudworm in millet according to claim 1, characterized in that: The method for using the attractant specifically comprises the following steps: S1, adding the attractant into the slow-release carrier, and then sealing it to make the attractant core; S2. Place the lure core on the trap and hang it in the rice field.

7. The method for using the attractant for Ophiocordyceps sinensis in millet according to claim 6, characterized in that: The sustained-release carrier is a polyethylene bottle.

8. The method for using the attractant for Ophiocordyceps sinensis in millet according to claim 6, characterized in that: The traps are arranged in a rectangular array in the valley field, with a density of 80-120 m 2 Set up a set of traps.

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