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Ward SE, Hoffmann AA, Van Helden M, Slavenko A, Umina PA. The effects of insecticide seed treatments on the parasitism and predation of Myzus persicae (Homoptera: Aphididae) in canola. J Econ Entomol 2024; 117:102-117. [PMID: 38142133 DOI: 10.1093/jee/toad236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 11/27/2023] [Accepted: 12/07/2023] [Indexed: 12/25/2023]
Abstract
The green peach aphid, Myzus persicae (Sulzer) (Homoptera: Aphididae), is a major pest of brassica plants, with the ability to transmit > 100 viruses. Although the adoption of Integrated Pest Management is increasing, chemical treatment remains the predominant method used to control M. persicae globally. Insecticide seed treatments, typically with neonicotinoid active ingredients, have become commonplace in canola crops, and are viewed as a "softer" alternative to foliar sprays but may nevertheless impact natural enemies of M. persicae. In this study, the effects of canola seed treatments, containing imidacloprid, thiamethoxam, and a mixture of thiamethoxam + lambda-cyhalothrin, were investigated on the parasitoid wasp, Aphidius colemani Viereck (Hymenoptera: Braconidae) and the green lacewing, Mallada signatus (Schneider) (Neuroptera: Chrysopidae), both important natural enemies of M. persicae. Laboratory trials were undertaken using whole plants, with lethal and sublethal effects assessed by measuring several traits. Compared with untreated plants, more aphid mummies were produced and more A. colemani were reared on plants treated with thiamethoxam + lambda-cyhalothrin and more aphid mummies were produced on imidacloprid plants. Imidacloprid reduced the time A. colemani spent searching for M. persicae and thiamethoxam reduced its cleaning time. However, after A. colemani were removed from treated plants, there were no such effects observed, suggesting these impacts were relatively short-lived. We found no significant effects of seed treatments on M. signatus. These results point to the complexity of ecotoxicology studies involving multiple trophic levels and indicate that seed treatments may have variable impacts on key fitness traits of natural enemies.
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Affiliation(s)
- Samantha E Ward
- Cesar Australia, Level 1, 95 Albert Street, Brunswick, VIC 3056, Australia
- Pest and Environmental Adaptation Research Group, School of BioSciences, Bio21 Institute, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Ary A Hoffmann
- Pest and Environmental Adaptation Research Group, School of BioSciences, Bio21 Institute, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Maarten Van Helden
- Entomology, South Australian Research and Development Institute, Waite Building, Waite Road, Urrbrae, SA 5064, Australia
- School of Agriculture, Food and Wine, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Alex Slavenko
- Cesar Australia, Level 1, 95 Albert Street, Brunswick, VIC 3056, Australia
| | - Paul A Umina
- Cesar Australia, Level 1, 95 Albert Street, Brunswick, VIC 3056, Australia
- Pest and Environmental Adaptation Research Group, School of BioSciences, Bio21 Institute, The University of Melbourne, Parkville, VIC 3010, Australia
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Ward SE, Umina PA, Parry H, Balfour‐Cunningham A, Cheng X, Heddle T, Holloway JC, Langley C, Severtson D, Helden MV, Hoffmann AA. Is what you see what you get? The relationship between field observed and laboratory observed aphid parasitism rates in canola fields. Pest Manag Sci 2022; 78:3596-3607. [PMID: 35604048 PMCID: PMC9545395 DOI: 10.1002/ps.7002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 05/17/2022] [Accepted: 05/23/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Estimating parasitoid abundance in the field can be difficult, even more so when attempting to quantify parasitism rates and the ecosystem service of biological control that parasitoids can provide. To understand how 'field observed' parasitism rates (in-field mummy counts) of the green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae) translate to 'laboratory observed' parasitism rates (laboratory-reared parasitoid counts), field work was undertaken in Australian canola fields, over the winter growing season. RESULTS Overall, laboratory observed parasitism was on average 2.4 times higher than field observed parasitism, with rates an average of four-fold higher in fields from South Australia. Total field observed and laboratory observed parasitism rates (OPRs) of M. persicae varied considerably across regions, but less so among fields within regions. As crop growth stage progressed, the incidence of field observed mummies increased. The incidence of total parasitoids reared also increased with crop growth stage, averaging 3.4% during flowering and reaching 14.4% during podding/senescing. Although there was a greater diversity of reared parasitoid species at later crop growth stages, the laboratory OPR was unaffected by parasitoid species. Diaeretiella rapae was the most commonly reared parasitoid, increasing in absolute abundance with crop growth stage. CONCLUSION These findings indicate that field mummy counts alone do not provide a clear representation of parasitism within canola fields. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Affiliation(s)
| | - Paul A. Umina
- School of BioSciences, Bio21 InstituteThe University of MelbourneParkvilleVictoriaAustralia
- Cesar AustraliaLevel 1, 95 Albert StreetBrunswickVictoriaAustralia
| | - Hazel Parry
- CSIRO Entomology, Black MountainCanberraACTAustralia
| | - Amber Balfour‐Cunningham
- Department of Primary Industries and Regional Development75 York RoadNorthamWestern AustraliaAustralia
| | - Xuan Cheng
- School of BioSciences, Bio21 InstituteThe University of MelbourneParkvilleVictoriaAustralia
| | - Thomas Heddle
- South Australian Research and Development Institute, EntomologyUrrbraeSouth AustraliaAustralia
| | - Joanne C. Holloway
- New South Wales Department of Primary Industries, Wagga Wagga Agricultural InstituteWagga WaggaNew South WalesAustralia
| | - Caitlin Langley
- New South Wales Department of Primary Industries, Wagga Wagga Agricultural InstituteWagga WaggaNew South WalesAustralia
| | - Dustin Severtson
- Department of Primary Industries and Regional Development75 York RoadNorthamWestern AustraliaAustralia
| | - Maarten Van Helden
- South Australian Research and Development Institute, EntomologyUrrbraeSouth AustraliaAustralia
- The University of AdelaideAdelaideSouth AustraliaAustralia
| | - Ary A. Hoffmann
- School of BioSciences, Bio21 InstituteThe University of MelbourneParkvilleVictoriaAustralia
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Van Helden M, Heddle T, Umina PA, Maino JL. Economic Injury Levels and Dynamic Action Thresholds for Diuraphis noxia (Hemiptera: Aphididae) in Australian Cereal Crops. J Econ Entomol 2022; 115:592-601. [PMID: 35061905 DOI: 10.1093/jee/toab272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Indexed: 06/14/2023]
Abstract
The Russian wheat aphid (Diuraphis noxia [Kurdjumov, Hemiptera: Aphididae], RWA) was first detected in Australia in 2016 and is threatening an annual cereal industry valued at nearly 10 billion AUD per annum. Considerable uncertainty surrounds the economic risk of D. noxia to Australian cereals, which limits cost-effective farm management decisions. Through a series of inoculated and non-inoculated field trials in 2018 and 2019 in south-eastern Australia, we generated a range of D. noxia pressure metrics under different growing conditions for barley, wheat, and durum wheat. Relative yield loss was best explained by the 'percentage of tillers with D. noxia' (%TwRWA) with 0.28% yield loss per percent of tillers with D. noxia, which is significantly lower than 0.46-0.48% for susceptible winter wheat varieties in dryland conditions in the United States. Highest infestation levels were typically reached around GS40-50. To develop an action threshold, we calculated the rate of increase in the %TwRWA through time at 0.021% per day per %TwRWA (with little variation across sites). This allowed prediction of the expected maximum %TwRWA based on observations post tillering (GS30) and the expected duration before GS50 is reached. For earlier growth stages (<GS30), we were unable to determine yield impact and action thresholds since cereal plants produce many new tillers between GS20 and GS30, which may compensate for feeding damage as reported in other studies. This research should improve the cost-effectiveness of management decisions involving D. noxia in Australian cereal production systems.
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Affiliation(s)
- Maarten Van Helden
- Entomology, South Australian Research and Development Institute, Main Waite Building, Waite Road, Urrbrae, SA 5064, Australia
- School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Waite Road, Urrbrae, SA 5064, Australia
| | - Thomas Heddle
- Entomology, South Australian Research and Development Institute, Main Waite Building, Waite Road, Urrbrae, SA 5064, Australia
| | - Paul A Umina
- Bio21 Institute, School of Biosciences, University of Melbourne, Melbourne, VIC 3010, Australia
- Cesar Australia, 95 Albert Street, Brunswick, VIC 3056, Australia
| | - James L Maino
- Cesar Australia, 95 Albert Street, Brunswick, VIC 3056, Australia
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Villate L, Morin E, Demangeat G, Van Helden M, Esmenjaud D. Control of Xiphinema index populations by fallow plants under greenhouse and field conditions. Phytopathology 2012; 102:627-634. [PMID: 22376084 DOI: 10.1094/phyto-01-12-0007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The dagger nematode Xiphinema index has a high economic impact in vineyards by direct pathogenicity and above all by transmitting the Grapevine fanleaf virus (GFLV). Agrochemicals have been largely employed to restrict the spread of GFLV by reducing X. index populations but are now banned. As an alternative to nematicides, the use of fallow plants between two successive vine crops was assessed. We selected plant species adapted to vineyard soils and exhibiting negative impact on nematodes and we evaluated their antagonistic effect on X. index in greenhouse using artificially infested soil, and in naturally infested vineyard conditions. The screening was conducted with plants belonging to the families Asteraceae (sunflower, marigold, zinnia, and nyjer), Poaceae (sorghum and rye), Fabaceae (white lupin, white melilot, hairy vetch, and alfalfa), Brassicaceae (rapeseed and camelina), and Boraginaceae (phacelia). In the greenhouse controlled assay, white lupin, nyjer, and marigold significantly reduced X. index populations compared with that of bare soil. The vineyard assay, designed to take into account the aggregative pattern of X. index distribution, revealed that marigold and hairy vetch are good candidates as cover crops to reduce X. index populations in vineyard. Moreover, this original experimental design could be applied to manage other soilborne pathogens.
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