Pub Date : 2024-05-15DOI: 10.30843/nzpp.2024.77.11778
Richard Falloon, Iain Kirkwood, Catia Delmiglio, C. Bleach, Jana Monk, Scott Clelland
Pomovirus solani (common name: potato mop-top virus, PMTV) was first recorded in New Zealand on 11 September 2018. In contrast, Spongospora subterranea, the vector of PMTV, was first recorded in New Zealand in 1909, and is widespread causing important diseases of potato. PMTV causes distortion on potato leaves, shoots and tubers, and was designated at the time of first record as an Unwanted Organism by the New Zealand Ministry for Primary Industries. Spongospora subterranea and PMTV can survive for long periods in soil and in alternative hosts, so multi-year non-potato crop rotations are important for limiting the diseases caused by these pathogens. Both pathogens can also survive in wastes from potato processing factories, so disposal of processing effluent should be avoided on paddocks likely to be used for potato crops. The first observation and timely reporting of PMTV symptoms by a potato processing company instigated an official biosecurity response to the virus ‘incursion’, although PMTV may have been present 1 or 2 years prior to this first record. Rapid establishment of a PMTV Technical Advisory Group, including relevant international expertise, and the advice it provided, effectively directed the prompt response to the PMTV ‘incursion’, and the Ministry for Primary Industries and Potatoes New Zealand (Inc.) swiftly and effectively developed capability for monitoring and management of the ‘incursion’. Efforts since then by the New Zealand potato industry have reduced potential impacts of PMTV in this country, as demonstrated by low incidence of the virus in seed potato crops in 2019/20 and 2020/21. This low incidence indicates that PMTV is not adversely affecting potato productivity in New Zealand, and that management of the virus ‘incursion’ has been effective.
{"title":"Potato mop-top virus: knowledge review, and evaluation of the biosecurity response to ‘incursion’ of this virus in New Zealand","authors":"Richard Falloon, Iain Kirkwood, Catia Delmiglio, C. Bleach, Jana Monk, Scott Clelland","doi":"10.30843/nzpp.2024.77.11778","DOIUrl":"https://doi.org/10.30843/nzpp.2024.77.11778","url":null,"abstract":"Pomovirus solani (common name: potato mop-top virus, PMTV) was first recorded in New Zealand on 11 September 2018. In contrast, Spongospora subterranea, the vector of PMTV, was first recorded in New Zealand in 1909, and is widespread causing important diseases of potato. PMTV causes distortion on potato leaves, shoots and tubers, and was designated at the time of first record as an Unwanted Organism by the New Zealand Ministry for Primary Industries. Spongospora subterranea and PMTV can survive for long periods in soil and in alternative hosts, so multi-year non-potato crop rotations are important for limiting the diseases caused by these pathogens. Both pathogens can also survive in wastes from potato processing factories, so disposal of processing effluent should be avoided on paddocks likely to be used for potato crops. The first observation and timely reporting of PMTV symptoms by a potato processing company instigated an official biosecurity response to the virus ‘incursion’, although PMTV may have been present 1 or 2 years prior to this first record. Rapid establishment of a PMTV Technical Advisory Group, including relevant international expertise, and the advice it provided, effectively directed the prompt response to the PMTV ‘incursion’, and the Ministry for Primary Industries and Potatoes New Zealand (Inc.) swiftly and effectively developed capability for monitoring and management of the ‘incursion’. Efforts since then by the New Zealand potato industry have reduced potential impacts of PMTV in this country, as demonstrated by low incidence of the virus in seed potato crops in 2019/20 and 2020/21. This low incidence indicates that PMTV is not adversely affecting potato productivity in New Zealand, and that management of the virus ‘incursion’ has been effective.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"5 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140975104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-18DOI: 10.30843/nzpp.2024.77.11777
J. Tyson, K. Mellow
Vine decline and trunk diseases have been observed in New Zealand kiwifruit orchards since the year 2000. In 2019, a block of Actinidia chinensis var. deliciosa ‘Hayward’ vines that were being re-grafted was noted to have differences in colouration of the internal wood of the cut trunks, with dark cores often corresponding with less vigorous vines and/or vines with trunk disorders. Cross-sections of 10 symptomatic and 10 externally asymptomatic trunks were taken from 1–1.5 m above the soil and fungal isolations made across the width of the trunks. Fungi found within the symptomatic vines included Neobulgaria alba, Ilyonectria spp., Neonectria microconidia, Gliomastix murorum, Clonostachys sp. and Penicillium sp. There was a wide variety of symptoms and fungal profiles seen. However, Neobulgaria alba often closely matched the stained areas seen in the wood and was not recovered from the asymptomatic vines. The most common fungus in the asymptomatic vines was Chaetomium sp. These isolations revealed a group of fungal genera that were associated with diseased trunks of kiwifruit at this site. Pathogenicity testing is needed to confirm which of these fungi are secondary invaders and which are primary pathogens of this host.
{"title":"Fungi found in association with discoloured wood of kiwifruit vines in New Zealand","authors":"J. Tyson, K. Mellow","doi":"10.30843/nzpp.2024.77.11777","DOIUrl":"https://doi.org/10.30843/nzpp.2024.77.11777","url":null,"abstract":"Vine decline and trunk diseases have been observed in New Zealand kiwifruit orchards since the year 2000. In 2019, a block of Actinidia chinensis var. deliciosa ‘Hayward’ vines that were being re-grafted was noted to have differences in colouration of the internal wood of the cut trunks, with dark cores often corresponding with less vigorous vines and/or vines with trunk disorders. Cross-sections of 10 symptomatic and 10 externally asymptomatic trunks were taken from 1–1.5 m above the soil and fungal isolations made across the width of the trunks. Fungi found within the symptomatic vines included Neobulgaria alba, Ilyonectria spp., Neonectria microconidia, Gliomastix murorum, Clonostachys sp. and Penicillium sp. There was a wide variety of symptoms and fungal profiles seen. However, Neobulgaria alba often closely matched the stained areas seen in the wood and was not recovered from the asymptomatic vines. The most common fungus in the asymptomatic vines was Chaetomium sp. These isolations revealed a group of fungal genera that were associated with diseased trunks of kiwifruit at this site. Pathogenicity testing is needed to confirm which of these fungi are secondary invaders and which are primary pathogens of this host.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":" 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140689259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-27DOI: 10.30843/nzpp.2024.77.11779
Thomas F. Carlin, Andrew J. Vautrin, Thomas Paul, Carol A. Rolando, Sam J. Davidson, Matthew B. Scott
Samara morphology, including weight, size, and wing-to-seed ratios, is an important precursor to seed dispersal, and therefore a primary driver in large-scale alien conifer invasions. Prior studies have not reported morphological differences between samaras of different cones within a tree possibly because cone position at differing crown heights has not been examined. This preliminary study investigated whether cones from different crown heights of three lodgepole pine (Pinus contorta Douglas) trees differ in the morphological characteristics of their samaras. Samaras from the lower tree crown were 17% heavier on average than those from the upper crown, without any significant differences in wing loading. Cones in the upper crown produced more seeds than in the lower crown, although this was inconsistent across the small sample size. These results suggest the effects on primary seed-dispersal are negligible, but further research is needed to determine the effect on secondary seed-dispersal. Larger seeds from the lower crown are better adapted to survive in a competitive environment near other trees, while cones in the upper crown may produce more, but smaller, seeds which could infer a bet-hedging strategy when dispersing into heterogeneous environments. These results suggest canopy-height should be considered when accounting for inter-cone variation in conifers.
{"title":"Conifer samara structure diverges across the height of the tree crown","authors":"Thomas F. Carlin, Andrew J. Vautrin, Thomas Paul, Carol A. Rolando, Sam J. Davidson, Matthew B. Scott","doi":"10.30843/nzpp.2024.77.11779","DOIUrl":"https://doi.org/10.30843/nzpp.2024.77.11779","url":null,"abstract":"Samara morphology, including weight, size, and wing-to-seed ratios, is an important precursor to seed dispersal, and therefore a primary driver in large-scale alien conifer invasions. Prior studies have not reported morphological differences between samaras of different cones within a tree possibly because cone position at differing crown heights has not been examined. This preliminary study investigated whether cones from different crown heights of three lodgepole pine (Pinus contorta Douglas) trees differ in the morphological characteristics of their samaras. Samaras from the lower tree crown were 17% heavier on average than those from the upper crown, without any significant differences in wing loading. Cones in the upper crown produced more seeds than in the lower crown, although this was inconsistent across the small sample size. These results suggest the effects on primary seed-dispersal are negligible, but further research is needed to determine the effect on secondary seed-dispersal. Larger seeds from the lower crown are better adapted to survive in a competitive environment near other trees, while cones in the upper crown may produce more, but smaller, seeds which could infer a bet-hedging strategy when dispersing into heterogeneous environments. These results suggest canopy-height should be considered when accounting for inter-cone variation in conifers.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"10 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140425382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-03DOI: 10.30843/nzpp.2023.76.11768
Maarten J Thiellier, Manjula Kularathna
Species of root-lesion nematode (Pratylenchus spp.) are associated with significant reductions in wheat yield in wheat-growing regions around the world. Of these, Pratylenchus thornei and P. neglectus are known to cause the highest damage to the Australasian wheat industry. New Zealand is known to produce high wheat yields on a per-hectare basis yet little research has been conducted to date to determine the effects of Pratylenchus spp. on the production of wheat in New Zealand. Therefore, as the first step towards filling this knowledge gap, the current research focused on conducting surveys to determine the population densities and distribution of Pratylenchus spp. in wheat-growing regions in Canterbury, South Island, New Zealand. Surveys were conducted at ten selected sites that were geographically distinct from each other. At six of the ten sites, lesion nematode populations were reported to be above the recorded Australian threshold of 2000 nematodes per kg of soil. In Australia, it’s been recorded that around 50% yield reductions can occur in intolerant wheat varieties when population densities reaches this number. Differences in population density within each location was also observed indicating the uneven distribution of lesion nematodes within a field. Morphological measurements of the nematodes collected from multiple sites during this study confirmed the presence of P. thornei and P. neglectus in Canterbury wheat-producing areas indicating a potential threat to the New Zealand wheat industry by root-lesion nematodes. Further studies need to be conducted to fully understand the situation and to develop management strategies to mitigate threats from nematodes.
{"title":"Evaluating the densities and distribution of root-lesion nematodes (Partylenchus spp.) in wheat grown in Canterbury, New Zealand","authors":"Maarten J Thiellier, Manjula Kularathna","doi":"10.30843/nzpp.2023.76.11768","DOIUrl":"https://doi.org/10.30843/nzpp.2023.76.11768","url":null,"abstract":"Species of root-lesion nematode (Pratylenchus spp.) are associated with significant reductions in wheat yield in wheat-growing regions around the world. Of these, Pratylenchus thornei and P. neglectus are known to cause the highest damage to the Australasian wheat industry. New Zealand is known to produce high wheat yields on a per-hectare basis yet little research has been conducted to date to determine the effects of Pratylenchus spp. on the production of wheat in New Zealand. Therefore, as the first step towards filling this knowledge gap, the current research focused on conducting surveys to determine the population densities and distribution of Pratylenchus spp. in wheat-growing regions in Canterbury, South Island, New Zealand. Surveys were conducted at ten selected sites that were geographically distinct from each other. At six of the ten sites, lesion nematode populations were reported to be above the recorded Australian threshold of 2000 nematodes per kg of soil. In Australia, it’s been recorded that around 50% yield reductions can occur in intolerant wheat varieties when population densities reaches this number. Differences in population density within each location was also observed indicating the uneven distribution of lesion nematodes within a field. Morphological measurements of the nematodes collected from multiple sites during this study confirmed the presence of P. thornei and P. neglectus in Canterbury wheat-producing areas indicating a potential threat to the New Zealand wheat industry by root-lesion nematodes. Further studies need to be conducted to fully understand the situation and to develop management strategies to mitigate threats from nematodes.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"91 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138606043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-27DOI: 10.30843/nzpp.2023.76.11776
R. Ganley, M. Kabir, R. McDougal, R. Bradshaw
Biological control of pathogens can be an important tool for long-term management of diseases. Species in the fungal genus Trichoderma have been used for a broad range of agricultural functions including biological control. Here we tested if isolates and mixes of Trichoderma spp. could be effective in reducing symptoms of dothistroma needle blight, caused by the foliar pathogen Dothistroma septosporum, on Pinus radiata. Pot trials with natural and artificial D. septosporum infection and field trials were undertaken. The majority of Trichoderma treatments were not significantly different from the control. However, in one experiment, the Trichoderma treatments significantly reduced disease symptoms in one seedlot but not in the other seedlot tested. Conversely, in the field trial, one Trichoderma treatment significantly increased symptoms in comparison to the control. PCR analysis indicated that Trichoderma can persist over time, 16 months after inoculation, in the soil P. radiata seedlings were grown in, however, further investigation is required. Overall, the results from our trials showed that the Trichoderma isolates and mixes tested were unable to control dothistroma needle blight in P. radiata and are not suitable as biological control agents.
{"title":"Testing Trichoderma species as biological agents for control of Dothistroma septosporum in Pinus radiata","authors":"R. Ganley, M. Kabir, R. McDougal, R. Bradshaw","doi":"10.30843/nzpp.2023.76.11776","DOIUrl":"https://doi.org/10.30843/nzpp.2023.76.11776","url":null,"abstract":"Biological control of pathogens can be an important tool for long-term management of diseases. Species in the fungal genus Trichoderma have been used for a broad range of agricultural functions including biological control. Here we tested if isolates and mixes of Trichoderma spp. could be effective in reducing symptoms of dothistroma needle blight, caused by the foliar pathogen Dothistroma septosporum, on Pinus radiata. Pot trials with natural and artificial D. septosporum infection and field trials were undertaken. The majority of Trichoderma treatments were not significantly different from the control. However, in one experiment, the Trichoderma treatments significantly reduced disease symptoms in one seedlot but not in the other seedlot tested. Conversely, in the field trial, one Trichoderma treatment significantly increased symptoms in comparison to the control. PCR analysis indicated that Trichoderma can persist over time, 16 months after inoculation, in the soil P. radiata seedlings were grown in, however, further investigation is required. Overall, the results from our trials showed that the Trichoderma isolates and mixes tested were unable to control dothistroma needle blight in P. radiata and are not suitable as biological control agents.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139233165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-04DOI: 10.30843/nzpp.2023.76.11770
Ashleigh M. Mosen, Yanan Guo, Berit Hassing, Carl H. Mesarich, Rosie E. Bradshaw
Spray-induced gene silencing (SIGS) involves exogenous spray applications of double-stranded RNA (dsRNA) molecules targeting specific genes, such as those essential to pathogens. This technique has shown great potential for controlling fungal pathogens of horticultural and agricultural plants, but few studies have evaluated its application to forest pathogens. Here we report the first demonstration of exogenous application of dsRNA molecules targeting a gene required for virulence in the foliar pine pathogen Dothistroma septosporum, the causal agent of Dothistroma needle blight (DNB). Constructs expressing sense and antisense dsRNAs were generated targeting a 509 bp fragment of the dothistromin toxin regulatory gene (DsAflR) in D. septosporum. DsAflR is required for the production of dothistromin, a phytotoxin essential for full pathogen virulence. We found that exogenous dsRNA is taken up and the RNA silencing mechanism is functional in D. septosporum through a series of in vitro and in planta trials, such as monitoring the uptake of fluorescently labelled DsAflR-dsRNA into the cell by confocal microscopy and quantifying the extent of gene silencing by quantitative Polymerase Chain Reaction (qPCR). In vitro applications of DsAflR-dsRNA to D. septosporum reduced the accumulation of DsAflR mRNA compared to controls and, in some cases, were found to be statistically significant, despite a high level of variability in the results. Our study also demonstrated a reduction in DNB symptoms on infected pine needles sprayed with DsAflR-dsRNA, which was further supported by a significant reduction in fungal biomass. This preliminary study highlights the potential for SIGS as a future management scheme for controlling the forest pathogen D. septosporum, as well as other forest pathogens.
{"title":"An RNA interference (RNAi) target with potential to control Dothistroma needle blight","authors":"Ashleigh M. Mosen, Yanan Guo, Berit Hassing, Carl H. Mesarich, Rosie E. Bradshaw","doi":"10.30843/nzpp.2023.76.11770","DOIUrl":"https://doi.org/10.30843/nzpp.2023.76.11770","url":null,"abstract":"Spray-induced gene silencing (SIGS) involves exogenous spray applications of double-stranded RNA (dsRNA) molecules targeting specific genes, such as those essential to pathogens. This technique has shown great potential for controlling fungal pathogens of horticultural and agricultural plants, but few studies have evaluated its application to forest pathogens. Here we report the first demonstration of exogenous application of dsRNA molecules targeting a gene required for virulence in the foliar pine pathogen Dothistroma septosporum, the causal agent of Dothistroma needle blight (DNB). Constructs expressing sense and antisense dsRNAs were generated targeting a 509 bp fragment of the dothistromin toxin regulatory gene (DsAflR) in D. septosporum. DsAflR is required for the production of dothistromin, a phytotoxin essential for full pathogen virulence. We found that exogenous dsRNA is taken up and the RNA silencing mechanism is functional in D. septosporum through a series of in vitro and in planta trials, such as monitoring the uptake of fluorescently labelled DsAflR-dsRNA into the cell by confocal microscopy and quantifying the extent of gene silencing by quantitative Polymerase Chain Reaction (qPCR). In vitro applications of DsAflR-dsRNA to D. septosporum reduced the accumulation of DsAflR mRNA compared to controls and, in some cases, were found to be statistically significant, despite a high level of variability in the results. Our study also demonstrated a reduction in DNB symptoms on infected pine needles sprayed with DsAflR-dsRNA, which was further supported by a significant reduction in fungal biomass. This preliminary study highlights the potential for SIGS as a future management scheme for controlling the forest pathogen D. septosporum, as well as other forest pathogens.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135548134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-25DOI: 10.30843/nzpp.2023.76.11773
Mark McNeill, Russell Croy, Chikako Van Koten, Shengjing Shi
Costelytra giveni is a serious pasture pest in New Zealand and accurate estimates of population densities are important to inform control measures. This species generally has a one-year life cycle so populations should either remain stable after eggs have hatched or decline due to larval mortality. Larval counts were obtained using a simple, standard and widely used sampling method from a series of soil cores collected from ryegrass research plots in Canterbury, New Zealand between 27 January and 16 June 2021 and a significant increase in population was recorded. Measurements on 27 January, 19 March and 5 May, represented only c. 8%, 25% and 63% of the mean densities measured on 16 June, respectively. The apparent increase in larvae is attributed to failure to find small 1st and 2nd instar individuals within the soil samples. Larvae increased in size as they transitioned from 1st to 3rd instar and later instar specimens were more easily discovered. An equation to describe the observed results provided date-related correction factors to allow a more realistic prediction of C. giveni larval densities in the winter following empirical larval counts. Larval counts measured on 27 January, 19 March, and 5 May, would need to be multiplied by 13, 4 and 1.6, respectively, to accurately estimate the larval density found on 16 June. This study showed that summer-autumn sampling using the current method can significantly underestimate winter C. giveni larval densities, potentially leading to unanticipated pasture production losses. Similar results were also found in 2022. While the equation provides a guide to population estimates, the caveat is that region and environment will influence population trends in any particular year.
{"title":"Timing is everything: Improving predictions of winter New Zealand grass grub densities and associated damage from summer and autumn larval counts","authors":"Mark McNeill, Russell Croy, Chikako Van Koten, Shengjing Shi","doi":"10.30843/nzpp.2023.76.11773","DOIUrl":"https://doi.org/10.30843/nzpp.2023.76.11773","url":null,"abstract":"Costelytra giveni is a serious pasture pest in New Zealand and accurate estimates of population densities are important to inform control measures. This species generally has a one-year life cycle so populations should either remain stable after eggs have hatched or decline due to larval mortality. Larval counts were obtained using a simple, standard and widely used sampling method from a series of soil cores collected from ryegrass research plots in Canterbury, New Zealand between 27 January and 16 June 2021 and a significant increase in population was recorded. Measurements on 27 January, 19 March and 5 May, represented only c. 8%, 25% and 63% of the mean densities measured on 16 June, respectively. The apparent increase in larvae is attributed to failure to find small 1st and 2nd instar individuals within the soil samples. Larvae increased in size as they transitioned from 1st to 3rd instar and later instar specimens were more easily discovered. An equation to describe the observed results provided date-related correction factors to allow a more realistic prediction of C. giveni larval densities in the winter following empirical larval counts. Larval counts measured on 27 January, 19 March, and 5 May, would need to be multiplied by 13, 4 and 1.6, respectively, to accurately estimate the larval density found on 16 June. This study showed that summer-autumn sampling using the current method can significantly underestimate winter C. giveni larval densities, potentially leading to unanticipated pasture production losses. Similar results were also found in 2022. While the equation provides a guide to population estimates, the caveat is that region and environment will influence population trends in any particular year.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"104 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135771094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-22DOI: 10.30843/nzpp.2023.76.11769
E. Gerard, C. van Koten, M. Schoof, T. James, M. O’Callaghan
Ripgut brome (Bromus diandrus) is a significant weed in arable systems with cereals being negatively impacted through yield reduction and contamination of harvested grain. There are limited herbicide options for its control, and reduction of the weed seed bank is a key part of its management. Ripgut brome seeds were incubated in three soils known to harbour a range of plant pathogens, and a range of fungi were subsequently isolated from ungerminated seeds. The most prevalent putative fungal pathogens isolated were Fusarium spp. and Marasmius sp. Selected isolates were cultured on artificial media and tested for their ability to inhibit germination of ripgut brome seeds in a series of in vitro assays, with many isolates completely inhibiting germination. When isolates were tested for their activity against non-target arable species in plant assays, three of five Fusarium spp. isolates significantly inhibited germination of oats and barley while a Marasmius sp. isolate had no effect on germination of these species. Further plant assays using four Marasmius sp. isolates against a wider range of plant species (oats, barley, ryegrass, brome, cocksfoot, and prairie grass) indicated some variability between Marasmius sp. isolates, with two isolates slightly inhibiting germination of some plant species, while two isolates (W14, W17) had no adverse effects. Sequencing of the ITS region of the Marasmius sp. isolates indicated that they were closely related but distinct from M. graminum, which is known to have some phytopathogenic activity and M. oreades which has not yet been reported as a plant pathogen. Further investigation of the Marasmius isolates as potential biocontrol agents for ripgut brome seed is warranted.
{"title":"Identification of potential fungal biocontrol agents for the management of ripgut brome","authors":"E. Gerard, C. van Koten, M. Schoof, T. James, M. O’Callaghan","doi":"10.30843/nzpp.2023.76.11769","DOIUrl":"https://doi.org/10.30843/nzpp.2023.76.11769","url":null,"abstract":"Ripgut brome (Bromus diandrus) is a significant weed in arable systems with cereals being negatively impacted through yield reduction and contamination of harvested grain. There are limited herbicide options for its control, and reduction of the weed seed bank is a key part of its management. Ripgut brome seeds were incubated in three soils known to harbour a range of plant pathogens, and a range of fungi were subsequently isolated from ungerminated seeds. The most prevalent putative fungal pathogens isolated were Fusarium spp. and Marasmius sp. Selected isolates were cultured on artificial media and tested for their ability to inhibit germination of ripgut brome seeds in a series of in vitro assays, with many isolates completely inhibiting germination. When isolates were tested for their activity against non-target arable species in plant assays, three of five Fusarium spp. isolates significantly inhibited germination of oats and barley while a Marasmius sp. isolate had no effect on germination of these species. Further plant assays using four Marasmius sp. isolates against a wider range of plant species (oats, barley, ryegrass, brome, cocksfoot, and prairie grass) indicated some variability between Marasmius sp. isolates, with two isolates slightly inhibiting germination of some plant species, while two isolates (W14, W17) had no adverse effects. Sequencing of the ITS region of the Marasmius sp. isolates indicated that they were closely related but distinct from M. graminum, which is known to have some phytopathogenic activity and M. oreades which has not yet been reported as a plant pathogen. Further investigation of the Marasmius isolates as potential biocontrol agents for ripgut brome seed is warranted.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"126 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78115733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-22DOI: 10.30843/nzpp.2023.76.11733
Jaeseung Lee, D. Kandula, John G. Hampton, Rainer Hofmann
Abstract: Red radish (Raphanus sativus) is highly susceptible to the soil-borne fungus Rhizoctonia solani, which can cause severe crop losses. In a glasshouse experiment, untreated seeds of radish cvs. French Breakfast and Red Round were grown in potting mix where R. solani inoculated wheat-bran was added at rates of 0.25, 0.5 and 1.0 g per 100 g potting mix. Seedling emergence was reduced by one third and two thirds respectively by the two higher inoculum rates, and final plant numbers were ca. 20%, 50% and 80% less than in the uninoculated control. The ability of Trichoderma spp. to increase radish yields by limiting the damage caused by R. solani has long been known but has not been evaluated in New Zealand. Inoculum of each of four Trichoderma spp. isolates LU132 (T. atroviride), LU785 (T. hamatum), LU1437 (T. harzianum) and LU1358 (T. polysporum) was prepared in sterile wheat-bran and 0.5 g wheat-bran was added per 100 g potting mix. In a second glasshouse experiment, R. solani (0.25 g inoculated wheat-bran) was added per 100 g potting mix before untreated seeds of both radish cultivars were sown. Potting mix without either R. solani or Trichoderma served as the control. Maximum seedling emergence did not differ among the treatments for cv. French Breakfast, but was increased by the presence of either isolate LU132 (T. atroviride) or LU1358 (T. polysporum) for cv. Red Round. The presence of isolate LU1347 (T. harzianum) in the potting mix significantly increased plant survival in both cultivars. Each of the four Trichoderma isolates reduced the percentage of diseased plants with isolate LU132 (T. atroviride) providing the strongest response. In a third glasshouse experiment, Trichoderma treated seeds, thiram fungicide treated and untreated seeds of both radish cultivars were sown in naturally R. solani infected soil. The same treatments were used in a field trial at a site known to be infected by R. solani. In the third glasshouse experiment, seed treatment with Trichoderma isolates LU1347 (T. harzianum), LU1358 (T. polysporum) and LU785 (T. hamatum) significantly increased bulb fresh weight in cv. Red Round, but no treatments increased bulb fresh weight in cv. French Breakfast. In the field experiment, bulb yield for the thiram seed treatment did not differ from that of the untreated control. However, seed treatment with isolate LU785 (T. hamatum) increased subsequent bulb yield by 96% for both cultivars, and seed treatment with isolate LU132 (T. atroviride) or isolate LU1358 (T. polysporum) also significantly increased bulb yield (by 85% and 60% respectively) in cv. French Breakfast. A possible explanation for this result was sought by undertaking a fourth glasshouse experiment for radish cv. Red Round only. In this experiment, all four Trichoderma spp. isolates more than doubled bulb yield by producing not only a greater number of bulbs but also larger bulbs than the untreated control. Trichoderma seed coating may provide an alternative t
摘要/ Abstract摘要:红萝卜(Raphanus sativus)对土壤真菌索拉根丝核菌(Rhizoctonia solani)非常敏感，可造成严重的作物损失。在一项温室实验中，未经处理的萝卜种子。在每100 g盆栽混合料中分别添加0.25、0.5和1.0 g接种过番茄红霉的麦麸，培养French Breakfast和Red Round。两种较高的接种量分别使幼苗出苗率降低了1 / 3和2 / 3，最终株数比未接种对照分别减少了约20%、50%和80%。木霉通过限制番茄枯萎病的危害来提高萝卜产量的能力早已为人所知，但在新西兰尚未进行评估。将4株木霉菌株LU132 (T. atroviride)、LU785 (T. hamatum)、LU1437 (T. harzianum)和LU1358 (T. polysporum)分别接种于无菌麦麸中，每100 g培养液中加入0.5 g麦麸。在第二个温室试验中，每100 g盆栽混合料中加入0.25 g接种过的麦麸，然后播种两种萝卜品种的种子。不含茄枯霉和木霉的盆栽混合液作为对照。不同处理间最大出苗率无显著差异。法国早餐，但增加了分离LU132 (T. atroviride)或LU1358 (T. polysporum)的cv。红色的圆。盆栽混合物中分离物LU1347 (T. harzianum)的存在显著提高了两个品种的植株成活率。4个木霉分离株均能降低病株率，其中LU132 (T. atroviride)的反应最强。在第三个温室试验中，将两种萝卜品种的木霉处理过的种子、杀真菌剂处理过的种子和未处理过的种子播种在天然茄枯菌感染的土壤上。同样的处理方法在一个已知被梭兰氏菌感染的地点进行了田间试验。在第三个温室试验中，分离木霉LU1347 (T. harzianum)、LU1358 (T. polysporum)和LU785 (T. hamatum)的种子处理显著提高了玉米鳞茎鲜重。但没有处理增加球茎鲜重。法国早餐。在田间试验中，施特兰种子处理后的鳞茎产量与未处理对照无显著差异。然而，用LU785 (T. hamatum)种子处理后，两个品种的鳞茎产量均提高了96%，用LU132 (T. atroviride)或LU1358 (T. polysporum)种子处理也显著提高了鳞茎产量(分别提高了85%和60%)。法国早餐。对萝卜cv进行了第四次温室试验，寻求对这一结果的可能解释。只有红轮。在本实验中，所有四株木霉菌株的球茎产量都比未经处理的对照增加了一倍以上，不仅球茎数量更多，而且球茎体积更大。木霉包衣为萝卜生产提供了一种替代杀菌剂种子处理的方法。
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Pub Date : 2023-05-18DOI: 10.30843/nzpp.2023.76.11771
M. Cripps, R. Falshaw
This editorial summarises the first 75 years of the New Zealand Plant Protection Society. The structure of the Society and approaches to plant protection have changed over the years but the essence of the original vision to bring together industry, government, and university researchers, to ‘pool and exchange information’, is still relevant today.
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