Patent Application
20240389558
This application is based upon and claims priority to Chinese Patent Application No. 202310608005.1, filed on May 26, 2023, the entire contents of which are incorporated herein by reference.
The present disclosure belongs to the technical field of biological control of agricultural pests, and specifically relates to a method for mass rearing of Telenomus remus.
Tobacco pests have always been a major problem affecting the production quality and benefit of flue-cured tobacco. Tobacco pests are mainly pests of the Noctuidae family in the order Lepidoptera. Spodoptera litura is present in all major flue-cured tobacco production areas in China. Spodoptera litura has characteristics such as many annual rearing generations, large occurrence quantity, strong concealment, and sudden outbreaks, and may cause huge economic losses to tobacco farmers. Pests of the Noctuidae family also threaten large agricultural systems other than tobacco systems. Spodoptera frugiperda is a major migratory pest widely present in the Americas. Spodoptera frugiperda spreads rapidly in China due to its characteristics, such as a wide suitable growth area range, strong migration, and high reproductivity, and causes major hazards to crops such as corn and rice. A large number of egg masses laid by adult noctuids is a source of hazards caused by noctuids in the field. Therefore, an egg stage is an important window period for the control of noctuids, and the use of efficient parasitoids for eggs of noctuids is particularly important for the long-term control of pests in the Noctuidae family.
The Telenomus remus, a member of the Scelionidae family in the order Hymenoptera, is a major parasitoid for eggs of pests in the Noctuidae family. As early as the 1970s, there had been relevant research reports on Telenomus remus outside China. So far, many countries in Latin America have achieved some success in controlling Spodoptera frugiperda by breeding Telenomus remus on a large scale with eggs of Spodoptera frugiperda or other hosts of the Noctuidae family. Some scholars in Brazil have successfully bred Telenomus remus with Corcyra cephalonica eggs. However, recent studies by Huo Liangxiao et al. and Dai Peng et al. have shown that the current breeding of Telenomus remus with Corcyra cephalonica eggs in China is unsuccessful. Some scholars in China have bred Telenomus remus with Spodoptera exigua eggs and have systematically observed the morphological characteristics of pest states during the ontogenetic process of Telenomus remus and the development stages of Telenomus remus. Huo Liangxiao et al. have bred Telenomus remus with Spodoptera litura and have observed biological characteristics of parasitism of Telenomus remus in Spodoptera litura. However, currently, Telenomus remus is still bred on a small scale in China. Thus, the establishment of a mass breeding technology system for Telenomus remus in China is of great significance for the long-term control of pests in the Noctuidae family. The screening of a desirable rearing host is a primary problem to be solved in many technologies to allow the mass breeding of Telenomus remus.
The technical problem to be solved by the present disclosure is to overcome the deficiencies in the prior art and to provide a method for mass rearing of Telenomus remus. In the present disclosure, the mass rearing of Telenomus remus is allowed creatively by screening egg sizes of Corcyra cephalonica eggs, which is of great significance for the long-term control of pests of the Noctuidae family.
To solve the above technical problem, the present disclosure adopts the following technical solutions:
A method for mass rearing of Telenomus remus is provided, including the following steps:
Preferably, a feed formula for feeding the Corcyra cephalonica in the step (2) includes the following components: a flour, a wheat bran, a soybean powder, a yeast powder, and a multivitamin; and
Preferably, the feed formula for feeding the Corcyra cephalonica in the step (2) includes the following components in weight percentages:
Preferably, the vitamin C, the riboflavin, the niacin, the calcium pantothenate, the pyridoxine, the biotin, the folic acid, the cobalamin, and the glucose in the multivitamin are in a weight ratio of (8-20):(15-40):(35-60):(35-60):(8-20):(0.1-5):(8-20):(0.1-5):(700-800).
Preferably, the establishing a Telenomus remus population of a Corcyra cephalonica strain in the step (1) includes the following steps:
Preferably, specific operations of the preparing a crude extract of Spodoptera litura eggs in the step (a) are as follows: collecting eggs laid by Spodoptera litura on the day, placing the eggs in a container, and adding a solvent to the container; sealing the container, gently shaking the container, and allowing the container to stand; and collecting a resulting supernatant.
Preferably, the Spodoptera litura is Spodoptera litura laying 500±50 eggs on the day, and a ratio of the female Telenomus remus to the Corcyra cephalonica eggs is 1:(8-12).
Preferably, the solvent is n-hexane, and the solvent is added in a volume of 2 μL to 10 μL.
Preferably, the female Telenomus remus of the Corcyra cephalonica strain inoculated in the step (3) are female Telenomus remus of the Corcyra cephalonica strain that undergo emergence within 24 h.
Preferably, in the step (3), a ratio of the female Telenomus remus of the Corcyra cephalonica strain to the Corcyra cephalonica eggs is 1:(8-12).
Due to the adoption of the above technical solutions, the present disclosure has the following advantages compared with the prior art:
FIGURE shows an impact of a crude extract of Spodoptera litura eggs on a residence time of Telenomus remus.
In order to make the technical solutions and beneficial effects of the present disclosure clear and comprehensible, specific embodiments are listed below for detailed description. It should be understood that these embodiments are provided merely to illustrate the present disclosure rather than limit the scope of the present disclosure. Any product that is the same as or similar to the product of the present disclosure and is obtained in light of the present disclosure or by combining the present disclosure with other features of the prior art shall fall within the protection scope of the present disclosure.
If specific techniques or conditions are not indicated in the following embodiments, an embodiment is usually implemented in accordance with the conventional techniques or conditions described in the literature in the prior art, or in accordance with conditions proposed by a product specification and a manufacturer.
Unless otherwise indicated, starting raw materials, materials, and reagents are commercially available or are synthesized according to known methods.
The present disclosure provides a method for mass rearing of Telenomus remus, including the following steps:
In some specific embodiments, a feed formula for feeding the Corcyra cephalonica in the step (2) includes the following components: a flour, a wheat bran, a soybean powder, a yeast powder, and a multivitamin.
In some specific embodiments, the multivitamin includes vitamin C, riboflavin, niacin, calcium pantothenate, pyridoxine, biotin, folic acid, cobalamin, and glucose.
In some specific embodiments, the feed formula for feeding the Corcyra cephalonica in the step (2) includes the following components in weight percentages:
In some specific embodiments, a weight percentage of the flour can be 65% to 90%, 70% to 90%, 70% to 85%, 75% to 85%, or 78% to 82% and more specifically can be 78%, 79%, 80%, 81%, or 82%.
In some specific embodiments, a weight percentage of the wheat bran can be 4% to 12% or 5% to 10% and more specifically can be 5%, 6%, 7%, 8%, 9%, or 10%.
In some specific embodiments, a weight percentage of the soybean powder can be 4% to 18%, 6% to 16%, or 8% to 12% and more specifically can be 8%, 9%, 10%, 11%, or 12%.
In some specific embodiments, a weight percentage of the yeast powder can be 1% to 5% and more specifically can be 1%, 2%, 3%, 4%, or 5%.
In some specific embodiments, a weight percentage of the multivitamin can be 0.5% to 1.8%, 0.7% to 1.5%, or 0.8% to 1.2% and more specifically can be 0.8%, 0.9%, 1%, 1.1%, or 1.2%.
In some specific embodiments, the vitamin C, the riboflavin, the niacin, the calcium pantothenate, the pyridoxine, the biotin, the folic acid, the cobalamin, and the glucose in the multivitamin can be in a weight ratio of (8-20):(15-40):(35-60):(35-60):(8-20):(0.1-5):(8-20):(0.1-5):(700-800), (10-18):(15-30):(40-60):(40-60):(10-18):(0.1-3):(10-18):(0.1-3):(700-800), or (10-15):(20-30):(45-55):(45-55):(10-15):(0.5-2):(10-15):(0.5-2):(700-800).
In a specific embodiment, the feed formula for feeding the Corcyra cephalonica in the step (2) includes the following components in weight percentages: the flour: 80%, the wheat bran: 7%, the soybean powder: 10%, the yeast powder: 2%, and the multivitamin: 1%, and the vitamin C, the riboflavin, the niacin, the calcium pantothenate, the pyridoxine, the biotin, the folic acid, the cobalamin, and the glucose in the multivitamin are in a weight ratio of 12.5:25:50:50:12.5:1:12.5:1:(700-800).
In some specific embodiments, a preparation method of a feed for feeding the Corcyra cephalonica in the step (2) includes the following steps:
In some specific embodiments, the establishing a Telenomus remus population of a Corcyra cephalonica strain in the step (1) includes the following steps:
In some specific embodiments, specific operations of the preparing a crude extract of Spodoptera litura eggs in the step (a) are as follows: eggs laid by Spodoptera litura on the day are collected and placed in a container, a solvent is added to the container, the container is sealed, gently shaken, and allowed to stand, and a resulting supernatant is collected.
In some specific embodiments, the Spodoptera litura is Spodoptera litura laying 500±50 eggs on the day, and a ratio of the female Telenomus remus to the Corcyra cephalonica eggs is 1:(8-12) and more specifically 1:8, 1:9, 1:10, 1:11, or 1:12.
In some specific embodiments, the solvent is n-hexane, and the n-hexane is added in a volume of 2 mL to 10 mL, 2 mL to 8 mL, or 2 mL to 6 mL and more specifically 2 mL, 3 mL, 4 mL, 5 mL, or 6 mL. If the amount of the solvent is too large, a concentration of the extract will be reduced, a concentration process will be long, and the volatilization will be severe. If the amount of the solvent is too small, the extract cannot cover the eggs.
In some specific embodiments, in the step (c), the crude extract of the Spodoptera litura eggs is added in a volume of 10 μL to 30 μL, 12 μL to 28 μL, 15 μL to 25 μL, or 18 μL to 22 μL and more specifically 18 μL, 19 μL, 20 μL, 21 μL, or 22 μL. If the amount of the crude extract is too large, a surface of the Corcyra cephalonica eggs will be in a wet state, and thus wings of Telenomus remus will stick to the surface, resulting in a failed parasitism. If the amount of the crude extract is too small, there will be an insufficient attraction effect.
In some specific embodiments, the female Telenomus remus inoculated in the step (c) is female Telenomus remus that undergo emergence within 24 h.
In some specific embodiments, environmental conditions of the artificial climate chamber in the step (4) are as follows: a temperature: 26±1° C., a relative humidity: 65±5%, and a photoperiod: L: D=14:10; and more specifically are as follows: a temperature: 27° C., a relative humidity: 70%, and a photoperiod: L: D=14:10 h.
In some specific embodiments, the female Telenomus remus of the Corcyra cephalonica strain inoculated in the step (3) is female Telenomus remus of a Corcyra cephalonica strain that undergo emergence within 24 h.
In some specific embodiments, in the step (3), a ratio of the female Telenomus remus of the Corcyra cephalonica strain to the Corcyra cephalonica eggs is 1:(8-12) and more specifically 1:8, 1:9, 1:10, 1:11, or 1:12.
The present disclosure also provides a feed formula and method for increasing a length of a long axis of a Corcyra cephalonica egg.
The feed formula for increasing a length of a long axis of a Corcyra cephalonica egg includes the following components: a flour, a wheat bran, a soybean powder, a yeast powder, and a multivitamin.
In some specific embodiments, the multivitamin includes vitamin C, riboflavin, niacin, calcium pantothenate, pyridoxine, biotin, folic acid, cobalamin, and glucose.
In some specific embodiments, the feed formula includes the following components in weight percentages:
In some specific embodiments, a weight percentage of the flour can be 65% to 90%, 70% to 90%, 70% to 85%, 75% to 85%, or 78% to 82% and more specifically can be 78%, 79%, 80%, 81%, or 82%.
In some specific embodiments, a weight percentage of the wheat bran can be 4% to 12% or 5% to 10% and more specifically can be 5%, 6%, 7%, 8%, 9%, or 10%.
In some specific embodiments, a weight percentage of the soybean powder can be 4% to 18%, 6% to 16%, or 8% to 12% and more specifically can be 8%, 9%, 10%, 11%, or 12%.
In some specific embodiments, a weight percentage of the yeast powder can be 1% to 5% and more specifically can be 1%, 2%, 3%, 4%, or 5%.
In some specific embodiments, a weight percentage of the multivitamin can be 0.5% to 1.8%, 0.7% to 1.5%, or 0.8% to 1.2% and more specifically can be 0.8%, 0.9%, 1%, 1.1%, or 1.2%.
In some specific embodiments, the vitamin C, the riboflavin, the niacin, the calcium pantothenate, the pyridoxine, the biotin, the folic acid, the cobalamin, and the glucose in the multivitamin can be in a weight ratio of (8-20):(15-40):(35-60):(35-60):(8-20):(0.1-5):(8-20):(0.1-5):(700-800), (10-18):(15-30):(40-60):(40-60):(10-18):(0.1-3):(10-18):(0.1-3):(700-800), or (10-15):(20-30):(45-55):(45-55):(10-15):(0.5-2):(10-15):(0.5-2):(700-800).
In a specific embodiment, the feed formula includes the following components in weight percentages: the flour: 80%, the wheat bran: 7%, the soybean powder: 10%, the yeast powder: 2%, and the multivitamin: 1%, and the vitamin C, the riboflavin, the niacin, the calcium pantothenate, the pyridoxine, the biotin, the folic acid, the cobalamin, and the glucose in the multivitamin are in a weight ratio of 12.5:25:50:50:12.5:1:12.5:1:(700-800).
A preparation method of the feed formula includes the following steps:
The method for increasing a length of a long axis of a Corcyra cephalonica egg is as follows: the Corcyra cephalonica egg is fed with the above feed formula under the following conditions: a temperature: 25±1° C., a relative humidity: 65%±5%, and a photoperiod: 14:10. The following raw materials, materials, or reagents are adopted in the examples below:
Telenomus remus is collected from egg masses of Spodoptera frugiperda in a corn field in Ruili City of Yunnan Province. A Telenomus remus population is established indoors. Spodoptera litura is collected from a tobacco field in Kunming City of Yunnan Province. A Spodoptera litura population is established indoors through sub-cultivation. Spodoptera litura eggs are egg masses collected indoors on the day. Corcyra cephalonica is provided by the Yunnan Agricultural University and has been bred indoors until now. Corcyra cephalonica eggs are eggs collected indoors on the day.
Establishment of a Telenomus remus Population of a Corcyra cephalonica Strain
About 500 Spodoptera litura eggs laid on the day were selected, swept off by a brush pen, and placed in a vial, then 4 mL of n-hexane was added to the vial, and the vial was sealed, shaken gently for 1 min, and then allowed to stand for 10 min. A resulting supernatant (namely, a crude extract of the Spodoptera litura eggs) was drawn out by a glass syringe, concentrated to 2 mL under high-purity nitrogen, and stored in a refrigerator at −18° C. for later use. Since volatiles could easily cause a contamination to affect an analysis result, the crude extract was concentrated by the inventors. Given a balance between a concentration and a number of use times, the crude extract was concentrated to 2 mL.
The experiment was conducted in a darkroom with red light.
1-1. Impact of the Crude Extract of Spodoptera litura Eggs on a Residence Time of Telenomus remus
In a treatment group, Corcyra cephalonica eggs laid on the day were collected and fixed on a sticker with a side length of 1 cm (about 120 to 150 eggs), then 20 μL of the crude extract was taken and added dropwise to the Corcyra cephalonica eggs, a female Telenomus remus that would undergo emergence within 24 h was placed in the middle of an egg mass, and timing was started to record a residence time of the female Telenomus remus on the egg mass. If the female Telenomus remus left a filter paper within 5 min and did not return within 20 min, the observation would be stopped. If the female Telenomus remus returned within 20 min, the observation would continue. In this experiment, Corcyra cephalonica eggs were adopted as a control group (the control group was different from the treatment group in that the crude extract was not added dropwise). Positions of the treatment group and the control group were exchanged after every 5 Telenomus remus were tested to avoid an impact of positions, wind, or the like on a result. In this experiment, 20 female Telenomus remus were tested, namely, 20 replicates.
1-2. Parasitism States of Telenomus remus in Corcyra cephalonica Eggs
In a treatment group, Corcyra cephalonica eggs laid on the day were collected and fixed on a sticker with a side length of 1 cm (about 120 to 150 eggs), then 20 μL of the crude extract was taken and added dropwise to the Corcyra cephalonica eggs, then female Telenomus remus that would undergo emergence within 24 h were inoculated according to a Telenomus remus/egg ratio of 1:10, and 15% honey water was added to provide nutrients for the female Telenomus remus. After 48 h of a parasitism, the Corcyra cephalonica eggs were taken out and fed in an artificial climate chamber under the environmental conditions of 27° C., RH=70%, and L: D=14:10 h, and spawn larvae were swept out in time. Egg masses were continuously cultivated until eggs turned black, indicating that the eggs were successfully parasitized. After 8 d of a parasitism, a parasitism state was observed under a stereoscopic microscope and a number of parasitic eggs was counted. Then, a parasitism was continued until Telenomus remus of a Corcyra cephalonica strain successfully emerged. In this experiment, Corcyra cephalonica eggs were adopted as a control group (the control group was different from the treatment group in that the crude extract was not added dropwise).
Parasitism rate (%)=number of parasitic eggs/number of total eggs*100%
Emergence rate (%)=number of emerged adult Telenomus remus/number of parasitic eggs*100%
2-1. The Impact of the Crude Extract of Spodoptera litura Eggs on a Residence Time of Telenomus remus is shown in the FIGURE.
It can be seen from the FIGURE that the use of the crude extract of Spodoptera litura eggs has a great impact on a residence time of Telenomus remus with a significant difference (P<0.05), and a residence time of Telenomus remus in the treatment group is 200 s and is 152 s higher than 48 s of the control group.
2-2. Parasitism States of Telenomus remus in Corcyra cephalonica Eggs are Shown in Table 1.
It can be seen from Table 1 that, in the treatment group, after the crude extract of Spodoptera litura eggs is added dropwise to the Corcyra cephalonica eggs, a small number of the Corcyra cephalonica eggs can be parasitized by Telenomus remus, but the emergence is unsuccessful, and after a parasitism rate is greatly increased during the 6th-generation and 7th-generation parasitisms and emergence is successful, an emergence rate is as high as about 25%, and then an emerged adult Telenomus remus is used as a parent seed Telenomus remus for continuous parasitism. An F1 generation has been bred, and the F1 generation refers to a first batch of bred Telenomus remus. However, Corcyra cephalonica eggs in the control group do not undergo a parasitism after 7 times of parasitism operations.
Impact of a size of Corcyra cephalonica eggs on a parasitism of Telenomus remus in the Corcyra cephalonica eggs
1-1. Preparation of a Feed for Corcyra cephalonica
The feed for Corcyra cephalonica was prepared as follows: A wheat bran was steamed for 60 min in a steaming box at 100° C., and a flour, a soybean powder, and a corn powder each were baked for 60 min in an oven at 100° C.; the treated components each were cooled and placed in a plastic box for later use; and then according to formulas A, B, C, D, and E, components of each formula were poured into a feed tray according to a specified ratio and thoroughly mixed to obtain five feeds A, B, C, D, and E for Corcyra cephalonica, respectively.
1-2. Impacts of Different Feed Formulas on Biological Indexes of Corcyra cephalonica
2,000 Corcyra cephalonica eggs were placed in each feed and fed under the following conditions: a temperature: 25±1° C., a relative humidity: 65%±5%, and a photoperiod: 14:10. The Corcyra cephalonica eggs were observed at any time, and the feed was added on time. Then a growth state of Corcyra cephalonica was observed every day. After Corcyra cephalonica adults emerged, 10 pairs of Corcyra cephalonica adults were randomly selected and placed in a plastic box to lay eggs, 20 eggs were selected from Corcyra cephalonica eggs collected on the first day and tested for a particle size, and then a number of eggs laid every day was counted until the Corcyra cephalonica adults died. Within 12 h after death of the Corcyra cephalonica adults, 10 intact Corcyra cephalonica adults were selected and tested for a body length.
1-3. Impact of a Size of Corcyra cephalonica Eggs on a Parasitism of Telenomus remus in the Corcyra cephalonica Eggs
10 pairs of Corcyra cephalonica adults were randomly selected from Corcyra cephalonica adults cultivated by each of two formulas to lay eggs, and eggs laid on the first day were adopted as test eggs. Corcyra cephalonica eggs obtained from formulas A and C were fixed on a sticker with a side length of 1 cm (about 120 to 150 eggs), then female Telenomus remus of a Corcyra cephalonica strain (obtained in Example 1) that would undergo emergence within 24 h were inoculated according to a Telenomus remus/egg ratio of 1:10, and 15% honey water was added to provide nutrients for the female Telenomus remus. After 48 h of a parasitism, the Corcyra cephalonica eggs were taken out and each were fed in an artificial climate chamber under the environmental conditions of 27° C., RH=70%, and L: D=14:10 h, and spawn larvae were swept out in time. After 8 d of a parasitism, a parasitism state was observed under a stereoscopic microscope and a number of parasitic eggs was counted. A parasitism rate and an emergence rate were calculated. For the subsequent 20th-generation to 30th-generation parasitisms, female Telenomus remus emerging in the previous generation were used to parasitize Corcyra cephalonica eggs, and then a parasitism rate and an emergence rate were detected every 5 generations.
Size of Female Corcyra cephalonica are Shown in Table 2.
It can be seen from Table 2 that Corcyra cephalonica fed with the formulas C, D, and E is better than Corcyra cephalonica fed with the formula A in terms of an egg yield, an adult body length, and an egg size.
2-2. An impact of a size of Corcyra cephalonica eggs on a parasitism of Telenomus remus in the Corcyra cephalonica eggs is shown in Table 3.
The above results show that, when large Corcyra cephalonica eggs are used as a substitute host, a parasitism rate of Telenomus remus for the Corcyra cephalonica eggs and an emergence rate of Telenomus remus are significantly increased after 30 consecutive generations of feeding of the Telenomus remus, which can allow the mass rearing.
It should be understood that the above embodiments are illustrative and are not intended to include all possible embodiments covered by the claims. Without departing from the scope of the present disclosure, various modifications and changes may be made on the basis of the above embodiments. Similarly, individual technical features of the above embodiments may be arbitrarily combined to produce an additional embodiment of the present disclosure that may not be explicitly described. Therefore, the above embodiments only express several implementations of the present disclosure, and do not limit the protection scope of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202310608005.1 | May 2023 | CN | national |
