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Geoff M. Gurr - One of the best experts on this subject based on the ideXlab platform.
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Alyssum (Lobularia maritima) selectively attracts and enhances the performance of Cotesia vestalis, a parasitoid of Plutella xylostella.
Scientific Reports, 2020Co-Authors: Yanting Chen, Olivia L. Reynolds, Wenbin Chen, Weiyi He, Geoff M. GurrAbstract:: The use of Nectar-providing Plants to nourish natural enemies of pest species has become a widely-used approach in conservation biological control to reduce pest damage without the indiscriminate use of insecticides. Choice of plant species is crucial to maximize benefits, but suitable species are yet to be identified for many important crop-pest systems. Here we explored the suitability of three candidate Nectar Plants for use in brassica vegetables to suppress the globally significant pest, Plutella xylostella L. (Lepidoptera: Plutellidae), using the widely-distributed parasitoid, Cotesia vestalis (Haliday) (Hymenoptera: Braconidae). Volatiles of alyssum (Lobularia maritima (L.) Desv) (Brassicaceae) were attractive to the parasitoid and access to flowering shoots increased adult longevity and realized fecundity of C. vestalis. Moreover, adult diamondback moth derived no benefit from this flower. In contrast, buckwheat (Fagopyrum esculentum Moench) (Polygonaceae), a species widely used in conservation biological control in other systems, increased the longevity and fecundity of both pest and parasitoid, rendering it less suitable. A third plant, heronsbill (Portulaca grandiflora Hook.) (Portulacaceae) denied benefit to the pest and promoted longevity of the parasitoid under no-choice conditions but did not improve fecundity and was repellent to female parasitoids under choice conditions. The contrasting effects of this set of Plants illustrate the need to test multiple response variables and effects on both pest and natural enemy when seeking optimal Nectar Plants for use in a novel conservation biological control system.
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Relevance of the ecological traits of parasitoid wasps and Nectariferous Plants for conservation biological control: a hybrid meta-analysis.
Pest Management Science, 2020Co-Authors: Xusong Zheng, Guihua Chen, Zhongxian Lu, Geoff M. GurrAbstract:BACKGROUND: Ecosystem services are key to human survival. In agriculture, they offer potential to intensify production while reducing reliance on hazardous inputs, including pesticides. Nectar Plants can nourish natural enemies of pests and thereby promote the ecosystem service of biological control. To date, however, the selection of optimal Plants has been reliant on laborious testing of multiple candidate species for use in each new agroecosystem. We report a hybrid meta-analysis of published literature, employing Bayesian network analysis. RESULTS: The hybrid meta-analysis identified the particular plant and parasitoid traits that were most predictive of promoted or suppressed parasitoid longevity. Integrating trait effects identified a combination of plant-parasitoid traits that had the highest impact on parasitoid longevity: compound umbel or raceme inflorescence form and shallow corolla, together with high potential fecundity of the parasitoid. CONCLUSION: Unlike earlier analyses focusing on taxonomic categories, we analysed effect sizes in relation to the ecological traits of parasitoids and Plants. This generated the first generalizable guidelines for selecting Nectar Plants as well as appropriate parasitoid targets for the enhancement of biological control. Within the guidelines, optimal outcomes resulted when Plants with compound umbel or raceme inflorescences and shallow corollas were combined with fecund parasitoids. More widely, this type of ecological trait-based meta-analysis opens a new avenue for optimising the delivery of other types of ecosystem services. This article is protected by copyright. All rights reserved.
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selection of Nectar Plants for use in ecological engineering to promote biological control of rice pests by the predatory bug cyrtorhinus lividipennis heteroptera miridae
PLOS ONE, 2014Co-Authors: Zhongxian Lu, Xusong Zheng, Yajun Yang, Guihua Chen, Geoff M. Gurr, Hongxing Xu, K. L. Heong, Helen NicolAbstract:Ecological engineering for pest management involves the identification of optimal forms of botanical diversity to incorporate into a farming system to suppress pests, by promoting their natural enemies. Whilst this approach has been extensively researched in many temperate crop systems, much less has been done for rice. This paper reports the influence of various plant species on the performance of a key natural enemy of rice planthopper pests, the predatory mirid bug, Cyrtorhinus lividipennis. Survival of adult males and females was increased by the presence of flowering Tagetes erecta, Trida procumbens, Emilia sonchifolia (Compositae), and Sesamum indicum (Pedaliaceae) compared with water or nil controls. All flower treatments resulted in increased consumption of brown plant hopper, Nilaparvata lugens, and for female C. lividipennis, S. indicum was the most favorable. A separate study with a wider range of plant species and varying densities of prey eggs showed that S. indicum most strongly promoted predation by C. lividipennis. Reflecting this, S. indicum gave a relatively high rate of prey search and low prey handling time. On this basis, S. indicum was selected for more detailed studies to check if its potential incorporation into the farming system would not inadvertently benefit Cnaphalocrocis medinalis and Marasmia patnalis, serious Lepidoptera pests of rice. Adult longevity and fecundity of both pests was comparable for S. indicum and water treatments and significantly lower than the honey solution treatment. Findings indicate that S. indicumis well suited for use as an ecological engineering plant in the margins of rice crops. Sesame indicum can be a valuable crop as well as providing benefits to C. lividipennis whilst denying benefit to key pests.
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laboratory screening supports the selection of sesame sesamum indicum to enhance anagrus spp parasitoids hymenoptera mymaridae of rice planthoppers
Biological Control, 2013Co-Authors: Geoff M. Gurr, Xusong Zheng, Guihua Chen, Zhongxian Lu, Hongxing Xu, K. L. Heong, Yajun YangAbstract:Abstract Planthopper (Delphacidae) pests have broken out frequently in Asia over the last decade leading to interest in enhancing the impact of natural enemies by growing Nectar Plants on the bunds that border rice fields. Such targeted use of plant diversity is popular in other crop systems but there is a marked lack of information on the scope for its use in rice, particularly the important aspect of which plant species to use. This study used Y-tube olfactometer assays to measure the response of two important parasitoids of delphacid pests to candidate Nectar Plants. Anagrus optabilis exhibited significant attraction to the air from six of the seven plant species whilst Anagrus nilaparvatae appeared more selective, exhibiting attraction to only seven of the 23 Plants screened and repulsion to one. Sesamum indicum , Emilia sonchifolia , and Impatiens balsamena were the only three Plants attractive to both parasitoids. Laboratory longevity of adult female A. nilaparvatae and A. optabilis with access to sesame flowers was significantly greater than with access to sesame from which the flowers were removed plus water. Similarly, both parasitoids parasitized significantly more brown planthopper ( Nilaparvatae lugens ) eggs in the presence of sesame flowers. Handling time of A. nilaparvatae was reduced from 31.29 to 18.36 min by access to sesame Nectar. Findings show that sesame has a marked beneficial effect on key parameters of Anagrus spp. and justifies further evaluation of its utility as a Nectar plant to improve biological control in Asian rice systems.
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parasitoids of the rice leaffolder cnaphalocrocis medinalis and prospects for enhancing biological control with Nectar Plants
Agricultural and Forest Entomology, 2012Co-Authors: Geoff M. Gurr, Donna M Y Read, Josie Lynn A Catindig, Jiuan Cheng, K. L. HeongAbstract:1 The rice leaffolder Cnaphalocrocis medinalis (Guenee) (Lepidoptera: Pyralidae) is a serious rice pest in Asia. The conspicuous foliar damage caused by C. medinalis larvae leads to early-season insecticide applications that disrupt the biological control of this and other pest species. 2 Despite the often dramatic impact of C. medinalis, rice Plants can tolerate severe defoliation with no impact on grain yield, although persuading farmers to withhold insecticide application has proven very difficult. 3 The present review assesses the prevention of damage caused by C. medinalis via biological control using parasitoids. Information on the indigenous parasitoids of C. medinalis is drawn together for the first time from the non-English literature published in Asia. This is integrated with the wider English language literature to provide a comprehensive analysis of the parasitoid fauna. 4 Survey studies have been conducted in many Asian countries in recent decades, showing that parasitoids of rice pests can achieve high rates of parasitism but are far from consistent as a mortality factor. There is much less work available on the biology of leaffolder parasitoids in rice and there is an unexpected dearth of studies regarding increasing their performance by providing Nectar sources, which is a widely explored approach for other crop systems. 5 It is concluded that the recently reported work in which Nectar Plants are established on rice bunds to support planthopper parasitoids may have significant benefit for leaffolder parasitoids. The use of plant species, however, that are selective in not allowing adult moths to feed will be essential.
Zhi-hua Ye - One of the best experts on this subject based on the ideXlab platform.
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The role of Nectar Plants in severe outbreaks of armyworm Mythimna separata (Lepidoptera: Noctuidae) in China.
Bulletin of Entomological Research, 2006Co-Authors: Gao-ping Wang, Qing-wen Zhang, Zhi-hua YeAbstract:: The period from March to mid April, when oriental armyworm Mythimna separata (Walker) moths migrate from South China to Central China over several nights, is an important window of time in annual armyworm population increase. The presence of Nectar sources along the pathway of the migratory population is a prerequisite for moths to reach target habitats and lay eggs. Using flowering periods and geographic distributions, the major spring Nectar Plants suitable for M. separata moths were identified from among 102 species/varieties of apicultural Nectar Plants. The Nectar Plants proposed as important to M. separata include milk vetch Astragalus sinicus L., rape Brassica napa L. and six other species. Spearman's rank correlation analyses were conducted between the annual population size of M. separata and the acreages of milk vetch and rape in the daily stopover areas for migrating populations of M. separata during 1950-1979. The Spearman's coefficient between milk vetch and M. separata was 0.6259 and the correlation was highly significant (P
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the role of Nectar Plants in severe outbreaks of armyworm mythimna separata lepidoptera noctuidae in china
Bulletin of Entomological Research, 2006Co-Authors: Gao-ping Wang, Qing-wen Zhang, Zhi-hua YeAbstract:: The period from March to mid April, when oriental armyworm Mythimna separata (Walker) moths migrate from South China to Central China over several nights, is an important window of time in annual armyworm population increase. The presence of Nectar sources along the pathway of the migratory population is a prerequisite for moths to reach target habitats and lay eggs. Using flowering periods and geographic distributions, the major spring Nectar Plants suitable for M. separata moths were identified from among 102 species/varieties of apicultural Nectar Plants. The Nectar Plants proposed as important to M. separata include milk vetch Astragalus sinicus L., rape Brassica napa L. and six other species. Spearman's rank correlation analyses were conducted between the annual population size of M. separata and the acreages of milk vetch and rape in the daily stopover areas for migrating populations of M. separata during 1950-1979. The Spearman's coefficient between milk vetch and M. separata was 0.6259 and the correlation was highly significant (P<0.001). Further regression analysis with data from 1950-1979 and from 1980-1992 also revealed a close relationship between annual acreage of damaged crops/wheat and acreage of milk vetch. These results strongly suggest that the unprecedented enlargement in the geographic distribution of milk vetch from Central China into South China was the key factor in the frequent severe oriental armyworm outbreaks that occurred during 1966-1977. This is thought to be the first report in the world that reveals the key role of Nectar sources in long distance, regional scale, migration of moths. The argument for the key role of milk vetch is supported by the simultaneous decline in the level of damage inflicted by M. separata and the acreage of milk vetch after 1980.
Yajun Yang - One of the best experts on this subject based on the ideXlab platform.
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selection of Nectar Plants for use in ecological engineering to promote biological control of rice pests by the predatory bug cyrtorhinus lividipennis heteroptera miridae
PLOS ONE, 2014Co-Authors: Zhongxian Lu, Xusong Zheng, Yajun Yang, Guihua Chen, Geoff M. Gurr, Hongxing Xu, K. L. Heong, Helen NicolAbstract:Ecological engineering for pest management involves the identification of optimal forms of botanical diversity to incorporate into a farming system to suppress pests, by promoting their natural enemies. Whilst this approach has been extensively researched in many temperate crop systems, much less has been done for rice. This paper reports the influence of various plant species on the performance of a key natural enemy of rice planthopper pests, the predatory mirid bug, Cyrtorhinus lividipennis. Survival of adult males and females was increased by the presence of flowering Tagetes erecta, Trida procumbens, Emilia sonchifolia (Compositae), and Sesamum indicum (Pedaliaceae) compared with water or nil controls. All flower treatments resulted in increased consumption of brown plant hopper, Nilaparvata lugens, and for female C. lividipennis, S. indicum was the most favorable. A separate study with a wider range of plant species and varying densities of prey eggs showed that S. indicum most strongly promoted predation by C. lividipennis. Reflecting this, S. indicum gave a relatively high rate of prey search and low prey handling time. On this basis, S. indicum was selected for more detailed studies to check if its potential incorporation into the farming system would not inadvertently benefit Cnaphalocrocis medinalis and Marasmia patnalis, serious Lepidoptera pests of rice. Adult longevity and fecundity of both pests was comparable for S. indicum and water treatments and significantly lower than the honey solution treatment. Findings indicate that S. indicumis well suited for use as an ecological engineering plant in the margins of rice crops. Sesame indicum can be a valuable crop as well as providing benefits to C. lividipennis whilst denying benefit to key pests.
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laboratory screening supports the selection of sesame sesamum indicum to enhance anagrus spp parasitoids hymenoptera mymaridae of rice planthoppers
Biological Control, 2013Co-Authors: Geoff M. Gurr, Xusong Zheng, Guihua Chen, Zhongxian Lu, Hongxing Xu, K. L. Heong, Yajun YangAbstract:Abstract Planthopper (Delphacidae) pests have broken out frequently in Asia over the last decade leading to interest in enhancing the impact of natural enemies by growing Nectar Plants on the bunds that border rice fields. Such targeted use of plant diversity is popular in other crop systems but there is a marked lack of information on the scope for its use in rice, particularly the important aspect of which plant species to use. This study used Y-tube olfactometer assays to measure the response of two important parasitoids of delphacid pests to candidate Nectar Plants. Anagrus optabilis exhibited significant attraction to the air from six of the seven plant species whilst Anagrus nilaparvatae appeared more selective, exhibiting attraction to only seven of the 23 Plants screened and repulsion to one. Sesamum indicum , Emilia sonchifolia , and Impatiens balsamena were the only three Plants attractive to both parasitoids. Laboratory longevity of adult female A. nilaparvatae and A. optabilis with access to sesame flowers was significantly greater than with access to sesame from which the flowers were removed plus water. Similarly, both parasitoids parasitized significantly more brown planthopper ( Nilaparvatae lugens ) eggs in the presence of sesame flowers. Handling time of A. nilaparvatae was reduced from 31.29 to 18.36 min by access to sesame Nectar. Findings show that sesame has a marked beneficial effect on key parameters of Anagrus spp. and justifies further evaluation of its utility as a Nectar plant to improve biological control in Asian rice systems.
Zhongxian Lu - One of the best experts on this subject based on the ideXlab platform.
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Relevance of the ecological traits of parasitoid wasps and Nectariferous Plants for conservation biological control: a hybrid meta-analysis.
Pest Management Science, 2020Co-Authors: Xusong Zheng, Guihua Chen, Zhongxian Lu, Geoff M. GurrAbstract:BACKGROUND: Ecosystem services are key to human survival. In agriculture, they offer potential to intensify production while reducing reliance on hazardous inputs, including pesticides. Nectar Plants can nourish natural enemies of pests and thereby promote the ecosystem service of biological control. To date, however, the selection of optimal Plants has been reliant on laborious testing of multiple candidate species for use in each new agroecosystem. We report a hybrid meta-analysis of published literature, employing Bayesian network analysis. RESULTS: The hybrid meta-analysis identified the particular plant and parasitoid traits that were most predictive of promoted or suppressed parasitoid longevity. Integrating trait effects identified a combination of plant-parasitoid traits that had the highest impact on parasitoid longevity: compound umbel or raceme inflorescence form and shallow corolla, together with high potential fecundity of the parasitoid. CONCLUSION: Unlike earlier analyses focusing on taxonomic categories, we analysed effect sizes in relation to the ecological traits of parasitoids and Plants. This generated the first generalizable guidelines for selecting Nectar Plants as well as appropriate parasitoid targets for the enhancement of biological control. Within the guidelines, optimal outcomes resulted when Plants with compound umbel or raceme inflorescences and shallow corollas were combined with fecund parasitoids. More widely, this type of ecological trait-based meta-analysis opens a new avenue for optimising the delivery of other types of ecosystem services. This article is protected by copyright. All rights reserved.
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selection of Nectar Plants for use in ecological engineering to promote biological control of rice pests by the predatory bug cyrtorhinus lividipennis heteroptera miridae
PLOS ONE, 2014Co-Authors: Zhongxian Lu, Xusong Zheng, Yajun Yang, Guihua Chen, Geoff M. Gurr, Hongxing Xu, K. L. Heong, Helen NicolAbstract:Ecological engineering for pest management involves the identification of optimal forms of botanical diversity to incorporate into a farming system to suppress pests, by promoting their natural enemies. Whilst this approach has been extensively researched in many temperate crop systems, much less has been done for rice. This paper reports the influence of various plant species on the performance of a key natural enemy of rice planthopper pests, the predatory mirid bug, Cyrtorhinus lividipennis. Survival of adult males and females was increased by the presence of flowering Tagetes erecta, Trida procumbens, Emilia sonchifolia (Compositae), and Sesamum indicum (Pedaliaceae) compared with water or nil controls. All flower treatments resulted in increased consumption of brown plant hopper, Nilaparvata lugens, and for female C. lividipennis, S. indicum was the most favorable. A separate study with a wider range of plant species and varying densities of prey eggs showed that S. indicum most strongly promoted predation by C. lividipennis. Reflecting this, S. indicum gave a relatively high rate of prey search and low prey handling time. On this basis, S. indicum was selected for more detailed studies to check if its potential incorporation into the farming system would not inadvertently benefit Cnaphalocrocis medinalis and Marasmia patnalis, serious Lepidoptera pests of rice. Adult longevity and fecundity of both pests was comparable for S. indicum and water treatments and significantly lower than the honey solution treatment. Findings indicate that S. indicumis well suited for use as an ecological engineering plant in the margins of rice crops. Sesame indicum can be a valuable crop as well as providing benefits to C. lividipennis whilst denying benefit to key pests.
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laboratory screening supports the selection of sesame sesamum indicum to enhance anagrus spp parasitoids hymenoptera mymaridae of rice planthoppers
Biological Control, 2013Co-Authors: Geoff M. Gurr, Xusong Zheng, Guihua Chen, Zhongxian Lu, Hongxing Xu, K. L. Heong, Yajun YangAbstract:Abstract Planthopper (Delphacidae) pests have broken out frequently in Asia over the last decade leading to interest in enhancing the impact of natural enemies by growing Nectar Plants on the bunds that border rice fields. Such targeted use of plant diversity is popular in other crop systems but there is a marked lack of information on the scope for its use in rice, particularly the important aspect of which plant species to use. This study used Y-tube olfactometer assays to measure the response of two important parasitoids of delphacid pests to candidate Nectar Plants. Anagrus optabilis exhibited significant attraction to the air from six of the seven plant species whilst Anagrus nilaparvatae appeared more selective, exhibiting attraction to only seven of the 23 Plants screened and repulsion to one. Sesamum indicum , Emilia sonchifolia , and Impatiens balsamena were the only three Plants attractive to both parasitoids. Laboratory longevity of adult female A. nilaparvatae and A. optabilis with access to sesame flowers was significantly greater than with access to sesame from which the flowers were removed plus water. Similarly, both parasitoids parasitized significantly more brown planthopper ( Nilaparvatae lugens ) eggs in the presence of sesame flowers. Handling time of A. nilaparvatae was reduced from 31.29 to 18.36 min by access to sesame Nectar. Findings show that sesame has a marked beneficial effect on key parameters of Anagrus spp. and justifies further evaluation of its utility as a Nectar plant to improve biological control in Asian rice systems.
Gao-ping Wang - One of the best experts on this subject based on the ideXlab platform.
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identification of summer Nectar Plants contributing to outbreaks of mythimna separata walker lepidoptera noctuidae in north china
Journal of Integrative Agriculture, 2018Co-Authors: Gao-ping Wang, H E Hanlin, Peiwen Zhou, L I Weizheng, Guohui YuanAbstract:Abstract The presence of adequate Nectar sources along the migratory pathway is a prerequisite for moths of oriental armyworm, Mythimna separata, to reach target habitats and lay eggs. Identification of plant species and assessment of their suitability as wild Nectar sources along the summer migration pathway of adult M. separata are critical steps in making effective forecasts of second- and third-generation armyworm outbreaks in North China. We explored five aspects of moth-Nectar source relationships: (1) Field investigations in 2014 and 2015 showed that the florescence of chaste tree, Vitex negundo var. heterophylla, a primary Nectar plant in apiculture, coincided with the summer migration of oriental armyworm moths. The flowers of chaste tree opened day and night and M. separata moths were found actively flying around and resting on tree. (2) Identification of moth-borne pollen by scanning electronic microscopy (SEM) micrographs in 2015 and 2016 revealed that 15.4% of 369 moths trapped by blacklight traps, 17.1% of 557 moths captured by vertical-pointing searchlight traps and 24.4% of 311 moths caught by pheromone traps were found with pollen attached to their proboscis. A total of 228 pollen-carrying individuals out of 1 237 armyworm moths were captured by the three types of traps. The three highest percentages of pollen-bearing armyworm moths were carrying pollen of Toona sp. (59.65%), Ligustrum sp. (27.19%) and Syringa sp. (4.39%). In total, 14 types of pollen were detected where three were identified to species, 10 to genus and one as an unknown species. (3) Analysis of geographical distribution, flowering periods and relative abundances of candidate Nectar Plants suggested that Chinese toon, Toona sinensis, and privet, Ligustrum lucidum, were two important Nectar plant species. (4) Analysis on relationship between pollen and ovarian development showed that 14, 15 and 10 females carrying pollen of T. sinensis had ovaries at developmental stages I, II and III, respectively. Many T. sinensis pollen grains were present on the proboscises of female moths. (5) Comparison of trap effectiveness between blacklight and vertical-pointing searchlight traps indicated blacklight traps caught the highest proportion (35.2%) of female in ovarian stage V, whereas vertical-pointing searchlight traps caught the highest proportion (43.5%) of female in ovarian stage I with additional proportions of decreasing percentages for stages II, III and IV. Integrated analysis on these five aspects suggests that T. sinensis is an important, suitable summer Nectar source that potentially influences migration and reproduction of M. separata moths and thus contributes to outbreaks of this pest. The vertical-pointing searchlight trap was the most effective tool for monitoring the migratory flight of adult M. separata Privet, Ligustrum lucidum, and clove, Syringa sp., are possible suitable summer Nectar Plants that need further study to elucidate their importance. The reason why field investigation results on chaste tree differed from the results of moth-borne pollen analyses was discussed.
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The role of Nectar Plants in severe outbreaks of armyworm Mythimna separata (Lepidoptera: Noctuidae) in China.
Bulletin of Entomological Research, 2006Co-Authors: Gao-ping Wang, Qing-wen Zhang, Zhi-hua YeAbstract:: The period from March to mid April, when oriental armyworm Mythimna separata (Walker) moths migrate from South China to Central China over several nights, is an important window of time in annual armyworm population increase. The presence of Nectar sources along the pathway of the migratory population is a prerequisite for moths to reach target habitats and lay eggs. Using flowering periods and geographic distributions, the major spring Nectar Plants suitable for M. separata moths were identified from among 102 species/varieties of apicultural Nectar Plants. The Nectar Plants proposed as important to M. separata include milk vetch Astragalus sinicus L., rape Brassica napa L. and six other species. Spearman's rank correlation analyses were conducted between the annual population size of M. separata and the acreages of milk vetch and rape in the daily stopover areas for migrating populations of M. separata during 1950-1979. The Spearman's coefficient between milk vetch and M. separata was 0.6259 and the correlation was highly significant (P
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the role of Nectar Plants in severe outbreaks of armyworm mythimna separata lepidoptera noctuidae in china
Bulletin of Entomological Research, 2006Co-Authors: Gao-ping Wang, Qing-wen Zhang, Zhi-hua YeAbstract:: The period from March to mid April, when oriental armyworm Mythimna separata (Walker) moths migrate from South China to Central China over several nights, is an important window of time in annual armyworm population increase. The presence of Nectar sources along the pathway of the migratory population is a prerequisite for moths to reach target habitats and lay eggs. Using flowering periods and geographic distributions, the major spring Nectar Plants suitable for M. separata moths were identified from among 102 species/varieties of apicultural Nectar Plants. The Nectar Plants proposed as important to M. separata include milk vetch Astragalus sinicus L., rape Brassica napa L. and six other species. Spearman's rank correlation analyses were conducted between the annual population size of M. separata and the acreages of milk vetch and rape in the daily stopover areas for migrating populations of M. separata during 1950-1979. The Spearman's coefficient between milk vetch and M. separata was 0.6259 and the correlation was highly significant (P<0.001). Further regression analysis with data from 1950-1979 and from 1980-1992 also revealed a close relationship between annual acreage of damaged crops/wheat and acreage of milk vetch. These results strongly suggest that the unprecedented enlargement in the geographic distribution of milk vetch from Central China into South China was the key factor in the frequent severe oriental armyworm outbreaks that occurred during 1966-1977. This is thought to be the first report in the world that reveals the key role of Nectar sources in long distance, regional scale, migration of moths. The argument for the key role of milk vetch is supported by the simultaneous decline in the level of damage inflicted by M. separata and the acreage of milk vetch after 1980.
