Pub Date : 2021-01-01DOI: 10.30843/nzpp.2021.74.11729
D. Mundy, M. Trought, A. McLachlan, S. Neal, Dominic Pecchenino
Mechanical fruit thinning could be a practical and cost-effective alternative to hand thinning of Sauvignon blanc grapes to increase quality by reducing yield. Botrytis bunch rot, caused by the fungus Botrytis cinerea, is the main seasonal disease risk for grapes grown in New Zealand but it is unknown if this disease is exacerbated by mechanical rather than manual thinning of the vines. It was hypothesised that the damage caused by mechanical thinning would result in more disease or increase disease pressure than hand thinning or no thinning. Botrytis bunch rot was determined in the field at harvest following mechanical thinning in the 2009, 2010 and 2011 seasons compared with an un-thinned control. In the 2011 season, possible mechanisms that may have influenced disease severity were investigated. The parameters investigated were: bunch openness; berry susceptibility to infection; and percentage of bunch debris infected with Botrytis cinerea. Mechanical thinning resulted in the same or lower observed disease severity compared with the un-thinned control in the 2009, 2010 and 2011 seasons while reducing yield as desired. In all seasons, both heavy and light machine thinning treatments reduced incidence of botrytis compared to the un-thinned control and the heavy machine treatment always reduced disease severity compared to the un-thinned control. Berry susceptibility to Botrytis cinerea was a complex interaction between various factors. Heavy machine thinned berries without wounding and inoculation were significantly less susceptible than the un-thinned control. Further investigation will be required to determine if the significant differences observed in berry susceptibility to infection and total infected bunch debris per bunch can be correlated with observed field disease levels.
{"title":"Effects of mechanical thinning on botrytis bunch rot on Sauvignon blanc wine grapes","authors":"D. Mundy, M. Trought, A. McLachlan, S. Neal, Dominic Pecchenino","doi":"10.30843/nzpp.2021.74.11729","DOIUrl":"https://doi.org/10.30843/nzpp.2021.74.11729","url":null,"abstract":"Mechanical fruit thinning could be a practical and cost-effective alternative to hand thinning of Sauvignon blanc grapes to increase quality by reducing yield. Botrytis bunch rot, caused by the fungus Botrytis cinerea, is the main seasonal disease risk for grapes grown in New Zealand but it is unknown if this disease is exacerbated by mechanical rather than manual thinning of the vines. It was hypothesised that the damage caused by mechanical thinning would result in more disease or increase disease pressure than hand thinning or no thinning. Botrytis bunch rot was determined in the field at harvest following mechanical thinning in the 2009, 2010 and 2011 seasons compared with an un-thinned control. In the 2011 season, possible mechanisms that may have influenced disease severity were investigated. The parameters investigated were: bunch openness; berry susceptibility to infection; and percentage of bunch debris infected with Botrytis cinerea. Mechanical thinning resulted in the same or lower observed disease severity compared with the un-thinned control in the 2009, 2010 and 2011 seasons while reducing yield as desired. In all seasons, both heavy and light machine thinning treatments reduced incidence of botrytis compared to the un-thinned control and the heavy machine treatment always reduced disease severity compared to the un-thinned control. Berry susceptibility to Botrytis cinerea was a complex interaction between various factors. Heavy machine thinned berries without wounding and inoculation were significantly less susceptible than the un-thinned control. Further investigation will be required to determine if the significant differences observed in berry susceptibility to infection and total infected bunch debris per bunch can be correlated with observed field disease levels.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"54 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84566463","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 : 2021-01-01DOI: 10.30843/nzpp.2021.74.11736
Alexa-Kate Byers, L. Condron, M. O’Callaghan, N. Waipara, A. Black
Phytophthora agathidicida is a highly virulent pathogen of kauri (Agathis australis) and the causal agent of dieback disease in New Zealand’s kauri forests. This study aimed to identify microbial isolates isolated from kauri forest soils that inhibited the growth of P. agathidicida. Three different forms of in vitro bioassays were used to assess the inhibition of each isolate on the mycelial growth of P. agathidicida. Furthermore, head space (HS) solid-phase micro-extraction coupled with gas chromatography-mass spectrometry (SPME-GCMS) was performed to identify if the microbial isolates emitted volatile organic compounds (VOCs), which may be contributing to inhibition. This research identified several bacterial isolates belonging to the genus Burkholderia that inhibited the mycelial growth of P. agathidicida. Furthermore, several VOCs produced by these isolates were putatively identified, which may be responsible for the inhibition observed in the bioassays. Several isolates of Penicillium were identified that inhibit Phytophthora agathidicida, with the culture filtrate of one isolate being found to strongly inhibit P. agathidicida mycelial growth. These isolates of Burkholderia and Penicillium appear to exhibit multiple modes of antagonism against P. agathidicida, including microbial competition and the production of diffusible and volatile anti-microbial compounds. Although further research is needed to better define their mechanisms of inhibition, these findings have identified candidate microbial antagonists of P. agathidicida.
{"title":"Identification of Burkholderia and Penicillium isolates from kauri (Agathis australis) soils that inhibit the mycelial growth of Phytophthora agathidicida","authors":"Alexa-Kate Byers, L. Condron, M. O’Callaghan, N. Waipara, A. Black","doi":"10.30843/nzpp.2021.74.11736","DOIUrl":"https://doi.org/10.30843/nzpp.2021.74.11736","url":null,"abstract":"Phytophthora agathidicida is a highly virulent pathogen of kauri (Agathis australis) and the causal agent of dieback disease in New Zealand’s kauri forests. This study aimed to identify microbial isolates isolated from kauri forest soils that inhibited the growth of P. agathidicida. Three different forms of in vitro bioassays were used to assess the inhibition of each isolate on the mycelial growth of P. agathidicida. Furthermore, head space (HS) solid-phase micro-extraction coupled with gas chromatography-mass spectrometry (SPME-GCMS) was performed to identify if the microbial isolates emitted volatile organic compounds (VOCs), which may be contributing to inhibition. This research identified several bacterial isolates belonging to the genus Burkholderia that inhibited the mycelial growth of P. agathidicida. Furthermore, several VOCs produced by these isolates were putatively identified, which may be responsible for the inhibition observed in the bioassays. Several isolates of Penicillium were identified that inhibit Phytophthora agathidicida, with the culture filtrate of one isolate being found to strongly inhibit P. agathidicida mycelial growth. These isolates of Burkholderia and Penicillium appear to exhibit multiple modes of antagonism against P. agathidicida, including microbial competition and the production of diffusible and volatile anti-microbial compounds. Although further research is needed to better define their mechanisms of inhibition, these findings have identified candidate microbial antagonists of P. agathidicida.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84222394","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 : 2020-12-11DOI: 10.30843/nzpp.2020.73.11721
Juliane Buhrdel, M. Walter, R. Campbell
The collection and visualisation of data in orchards are important for management of many orchard processes, including pests and diseases. We present methods combining visualising data with efficient, accurate, standardised data collection, using European canker in apple orchards as an exemplar. Using growercollected current and historical disease data, we investigated Environmental Systems Research Institute (ESRI) ArcGIS tools to analyse and visualise data. Historical data were collected by growers on paper and current data, also collected by growers, using Survey123. ArcGIS Pro was the operating software for analysis, and ArcGIS Online, Web Maps and ArcGIS Dashboards, for visualisation. Data collection, summarising and visualisation were more efficient using Survey123, than paper collection and subsequent data entry. Higher quality data, including spatial location of the disease, informed disease patterns. A standardised geodatabase enabled efficient data querying and analytics to understand disease distribution and temporal dynamics. This study exemplars a standardised disease and pest database to benefit both scientific and industry data management. Geodata collection, combined with visualisation, facilitates the use of data to understand disease and pest dynamics. These techniques offer opportunity for a cohesive industry approach to area-wide disease and pest monitoring and management, integrating previously disparate datasets by using location.
{"title":"Geodata collection and visualisation in orchards: interfacing science-grower data using a disease example (European canker in apple, Neonectria ditissima)","authors":"Juliane Buhrdel, M. Walter, R. Campbell","doi":"10.30843/nzpp.2020.73.11721","DOIUrl":"https://doi.org/10.30843/nzpp.2020.73.11721","url":null,"abstract":"The collection and visualisation of data in orchards are important for management of many orchard processes, including pests and diseases. We present methods combining visualising data with efficient, accurate, standardised data collection, using European canker in apple orchards as an exemplar. Using growercollected current and historical disease data, we investigated Environmental Systems Research Institute (ESRI) ArcGIS tools to analyse and visualise data. Historical data were collected by growers on paper and current data, also collected by growers, using Survey123. ArcGIS Pro was the operating software for analysis, and ArcGIS Online, Web Maps and ArcGIS Dashboards, for visualisation. Data collection, summarising and visualisation were more efficient using Survey123, than paper collection and subsequent data entry. Higher quality data, including spatial location of the disease, informed disease patterns. A standardised geodatabase enabled efficient data querying and analytics to understand disease distribution and temporal dynamics. This study exemplars a standardised disease and pest database to benefit both scientific and industry data management. Geodata collection, combined with visualisation, facilitates the use of data to understand disease and pest dynamics. These techniques offer opportunity for a cohesive industry approach to area-wide disease and pest monitoring and management, integrating previously disparate datasets by using location.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"50 1","pages":"57-64"},"PeriodicalIF":0.0,"publicationDate":"2020-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85749899","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 : 2020-11-19DOI: 10.30843/nzpp.2020.73.11713
A. Ahebwa, R. Mongkol, P. Sawangsri, M. Kanjanamaneesathian
Grain storage plays a crucial role in ensuring food security to Thai farmers so sustainable protection methods against deleterious microorganisms, such as fungi, are necessary. Essential oils (EOs) have demonstrated broad-spectrum fumigant antifungal activity against most storage fungi that are problematic in Thailand. Four storage fungi (Aspergillus flavus, A. niger, Curvularia lunata and Fusarium proliferatum) were isolated from dried rice and corn grains (stored for at least six months). EOs were extracted by hydrodistillation from clove buds (Syzygium aromaticum), fruit peel and leaves of makrut lime (Citrus hystrix), eucalyptus leaves (Eucalyptus sp.) and lemongrass stems (Cymbopogon citratus). The fungi inoculated on PDA in plastic cups were exposed to each EO vapour originating from paper disc attached in the lids in an inverted position. The minimum inhibitory concentration (MIC) for each EO was determined. Selected MICs were combined in a binary manner and similarly tested against the fungi. Fractional inhibitory concentration indices (FICI) were determined for each combination. Lemongrass and makrut lime leaf EOs were the most effective with MICs of 0.09 μL/mL against Curvularia lunata and 0.19-0.28 μL/mL against A. flavus, A. niger and F. proliferatum. Eucalyptus oil produced the least effective vapour (MIC 0.56-0.74 μL/mL) against all tested pathogens. A combination of lemongrass and makrut lime leaf EOs was partially synergistic against A. niger (FICI=0.75) but was fully synergistic against the other three fungi tested (FICI=0.5). The EOs from lemongrass and makrut lime leaf have potential to suppress the growth of the four grain-storage fungi tested.
{"title":"Vapour-phase efficacy of selected essential oils individually and in combination against Aspergillus flavus, A. niger, Fusarium proliferatum, and Curvularia lunata","authors":"A. Ahebwa, R. Mongkol, P. Sawangsri, M. Kanjanamaneesathian","doi":"10.30843/nzpp.2020.73.11713","DOIUrl":"https://doi.org/10.30843/nzpp.2020.73.11713","url":null,"abstract":"Grain storage plays a crucial role in ensuring food security to Thai farmers so sustainable protection methods against deleterious microorganisms, such as fungi, are necessary. Essential oils (EOs) have demonstrated broad-spectrum fumigant antifungal activity against most storage fungi that are problematic in Thailand. Four storage fungi (Aspergillus flavus, A. niger, Curvularia lunata and Fusarium proliferatum) were isolated from dried rice and corn grains (stored for at least six months). EOs were extracted by hydrodistillation from clove buds (Syzygium aromaticum), fruit peel and leaves of makrut lime (Citrus hystrix), eucalyptus leaves (Eucalyptus sp.) and lemongrass stems (Cymbopogon citratus). The fungi inoculated on PDA in plastic cups were exposed to each EO vapour originating from paper disc attached in the lids in an inverted position. The minimum inhibitory concentration (MIC) for each EO was determined. Selected MICs were combined in a binary manner and similarly tested against the fungi. Fractional inhibitory concentration indices (FICI) were determined for each combination. Lemongrass and makrut lime leaf EOs were the most effective with MICs of 0.09 μL/mL against Curvularia lunata and 0.19-0.28 μL/mL against A. flavus, A. niger and F. proliferatum. Eucalyptus oil produced the least effective vapour (MIC 0.56-0.74 μL/mL) against all tested pathogens. A combination of lemongrass and makrut lime leaf EOs was partially synergistic against A. niger (FICI=0.75) but was fully synergistic against the other three fungi tested (FICI=0.5). The EOs from lemongrass and makrut lime leaf have potential to suppress the growth of the four grain-storage fungi tested.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"16 1","pages":"40-48"},"PeriodicalIF":0.0,"publicationDate":"2020-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74283992","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 : 2020-11-19DOI: 10.30843/nzpp.2020.73.11722
J. Mills, S. Jackman, C. Koten, M. Cripps
The leaf-feeding beetle, Cassida rubiginosa, is an oligophagous biocontrol agent capable of feeding on most species in the tribe Cardueae (thistles and knapweeds). The beetle was released in New Zealand in 2007, primarily to control Cirsium arvense (Californian thistle), with the recognition that it had potential to control multiple thistle weeds. The objective of this study was to test the impact of different densities of Cassida rubiginosa larvae (0, 50, 100, or 200 per plant) on the growth and reproductive performance of the annual thistle weed, Carduus pycnocephalus (slender winged thistle). Since the effectiveness of biocontrol agents is often enhanced when plants are stressed, different levels of growth constraint were imposed by growing the weed in different pot sizes (0.5, 1, 5, and 12 litres). We hypothesised that feeding damage by Cassida rubiginosa larvae would have a greater impact on the weed when grown in smaller pots, since root growth would be constrained, and the weed’s ability to compensate for feeding damage would be restricted. Contrary to our hypothesis, pot size had no effect on feeding damage by Cassida rubiginosa on Carduus pycnocephalus. As expected, most measures of plant performance increased with larger pot sizes, including plant height, biomass, and the number of seedheads per plant. The results of this study indicate that Cassida rubiginosa is unlikely to contribute to the control of Carduus pycnocephalus. Additional oligophagous biocontrol agents targeting the rosette stage and seed production should be considered for release in New Zealand.
{"title":"The leaf-feeding beetle, Cassida rubiginosa, has no impact on Carduus pycnocephalus (slender winged thistle) regardless of physical constraints on plant growth","authors":"J. Mills, S. Jackman, C. Koten, M. Cripps","doi":"10.30843/nzpp.2020.73.11722","DOIUrl":"https://doi.org/10.30843/nzpp.2020.73.11722","url":null,"abstract":"The leaf-feeding beetle, Cassida rubiginosa, is an oligophagous biocontrol agent capable of feeding on most species in the tribe Cardueae (thistles and knapweeds). The beetle was released in New Zealand in 2007, primarily to control Cirsium arvense (Californian thistle), with the recognition that it had potential to control multiple thistle weeds. The objective of this study was to test the impact of different densities of Cassida rubiginosa larvae (0, 50, 100, or 200 per plant) on the growth and reproductive performance of the annual thistle weed, Carduus pycnocephalus (slender winged thistle). Since the effectiveness of biocontrol agents is often enhanced when plants are stressed, different levels of growth constraint were imposed by growing the weed in different pot sizes (0.5, 1, 5, and 12 litres). We hypothesised that feeding damage by Cassida rubiginosa larvae would have a greater impact on the weed when grown in smaller pots, since root growth would be constrained, and the weed’s ability to compensate for feeding damage would be restricted. Contrary to our hypothesis, pot size had no effect on feeding damage by Cassida rubiginosa on Carduus pycnocephalus. As expected, most measures of plant performance increased with larger pot sizes, including plant height, biomass, and the number of seedheads per plant. The results of this study indicate that Cassida rubiginosa is unlikely to contribute to the control of Carduus pycnocephalus. Additional oligophagous biocontrol agents targeting the rosette stage and seed production should be considered for release in New Zealand.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"80 1","pages":"49-56"},"PeriodicalIF":0.0,"publicationDate":"2020-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86633413","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 : 2020-11-15DOI: 10.30843/nzpp.2020.73.11711
R. Moukarzel, H. Ridgway, A. Guerin-Laguette, E. Jones
Arbuscular mycorrhizal fungi (AMF) establish symbiotic interactions with the roots of vascular plants, including grapevines. Verifying AMF colonisation routinely requires establishing the presence of hyphae, arbuscules and vesicles. Clearing roots with potassium hydroxide (KOH) followed by staining with trypan blue has been used previously to visualise fungal structures, however visualisation is difficult with darkly pigmented roots, such as those of grapevines so additional steps are required to ensure clear visualisation. Three fixing and clearing processes were evaluated prior to staining with trypan blue: 1) fixing grapevine roots in 70% v/v ethanol overnight; 2) clearing by heating the roots in either 2% or 10% w/v KOH; and 3) clearing the roots in 3% v/v hydrogen peroxide for 10 min. Roots were examined under a compound light microscope for the presence of AMF. A combination of fixing grapevine roots in 70% ethanol overnight and clearing by autoclaving in 10% KOH produced the greatest enhancement in subsequent staining of grapevine roots with trypan blue overnight. The best method tested enabled the discrimination of arbuscular mycorrhizal structures in fresh roots of grapevines without the use of toxic chemical fixatives.
{"title":"An improved clearing and staining protocol for evaluation of arbuscular mycorrhizal colonisation in darkly pigmented woody roots","authors":"R. Moukarzel, H. Ridgway, A. Guerin-Laguette, E. Jones","doi":"10.30843/nzpp.2020.73.11711","DOIUrl":"https://doi.org/10.30843/nzpp.2020.73.11711","url":null,"abstract":"Arbuscular mycorrhizal fungi (AMF) establish symbiotic interactions with the roots of vascular plants, including grapevines. Verifying AMF colonisation routinely requires establishing the presence of hyphae, arbuscules and vesicles. Clearing roots with potassium hydroxide (KOH) followed by staining with trypan blue has been used previously to visualise fungal structures, however visualisation is difficult with darkly pigmented roots, such as those of grapevines so additional steps are required to ensure clear visualisation. Three fixing and clearing processes were evaluated prior to staining with trypan blue: 1) fixing grapevine roots in 70% v/v ethanol overnight; 2) clearing by heating the roots in either 2% or 10% w/v KOH; and 3) clearing the roots in 3% v/v hydrogen peroxide for 10 min. Roots were examined under a compound light microscope for the presence of AMF. A combination of fixing grapevine roots in 70% ethanol overnight and clearing by autoclaving in 10% KOH produced the greatest enhancement in subsequent staining of grapevine roots with trypan blue overnight. The best method tested enabled the discrimination of arbuscular mycorrhizal structures in fresh roots of grapevines without the use of toxic chemical fixatives.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"30 1","pages":"33-39"},"PeriodicalIF":0.0,"publicationDate":"2020-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83320745","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 : 2020-10-27DOI: 10.30843/nzpp.2020.73.11718
M. Cripps, Jovesa Navukula, B. Kaltenbach, C. Koten, S. Casonato, H. Gourlay
The gall fly, Urophora stylata, was released in New Zealand in 1998 as a biocontrol agent against the thistle weed, Cirsium vulgare (Scotch thistle). In the summer of 2018, a survey was conducted to assess the field host range of the biocontrol agent in New Zealand. A random selection of 18 pasture populations under sheep and/or beef production, where C. vulgare was present, was surveyed to quantify the attack intensity (gall size relative to seedhead size) on C. vulgare, and the attack rate on other thistle weeds within the same population. At each location, seedheads were collected from C. vulgare and all other thistle species (Cardueae) present, which included Cirsium arvense (Californian thistle), Cirsium palustre (marsh thistle), Carduus nutans (nodding thistle), and an Arctium species (burdock). In addition to Cirsium vulgare, the gall fly was recorded on C. arvense (six locations) and C. palustre (one location). The probability of attack on C. arvense was positively correlated with attack intensity on C. vulgare, suggesting that attack on C. arvense is a ‘spill-over effect’ occurring where seedheads of C. vulgare are in limited supply.
{"title":"Spill-over attack by the gall fly, Urophora stylata, on congeners of its target weed, Cirsium vulgare","authors":"M. Cripps, Jovesa Navukula, B. Kaltenbach, C. Koten, S. Casonato, H. Gourlay","doi":"10.30843/nzpp.2020.73.11718","DOIUrl":"https://doi.org/10.30843/nzpp.2020.73.11718","url":null,"abstract":"The gall fly, Urophora stylata, was released in New Zealand in 1998 as a biocontrol agent against the thistle weed, Cirsium vulgare (Scotch thistle). In the summer of 2018, a survey was conducted to assess the field host range of the biocontrol agent in New Zealand. A random selection of 18 pasture populations under sheep and/or beef production, where C. vulgare was present, was surveyed to quantify the attack intensity (gall size relative to seedhead size) on C. vulgare, and the attack rate on other thistle weeds within the same population. At each location, seedheads were collected from C. vulgare and all other thistle species (Cardueae) present, which included Cirsium arvense (Californian thistle), Cirsium palustre (marsh thistle), Carduus nutans (nodding thistle), and an Arctium species (burdock). In addition to Cirsium vulgare, the gall fly was recorded on C. arvense (six locations) and C. palustre (one location). The probability of attack on C. arvense was positively correlated with attack intensity on C. vulgare, suggesting that attack on C. arvense is a ‘spill-over effect’ occurring where seedheads of C. vulgare are in limited supply.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"103 1","pages":"24-32"},"PeriodicalIF":0.0,"publicationDate":"2020-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75450357","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 : 2020-09-19DOI: 10.30843/nzpp.2020.73.11712
B. Richardson, C. Rolando, A. Hewitt, M. Kimberley
Large areas of New Zealand are being aerially sprayed with herbicides to manage ‘wilding’ conifer spread. The purpose of the study was to obtain and analyse droplet spectra produced by nozzles commonly used for wilding conifer spraying to determine whether or not operational recommendations for a target droplet size class (~350 μm) are being met. Droplet spectra were measured in a wind tunnel for 27 nozzle × 3 operating condition (nozzle angle, air speed and pressure) combinations tested for each of three spray mixes. AGDISP, an aerial spray application simulation model, was used to quantify the field performance implications of changes to droplet spectra parameters. Only one nozzle, the CP-09, 0.078, 30°, met the target droplet size specification when used at 45° but not at 0°. However, under these conditions, this nozzle produced a large driftable fraction. All but one of the other scenarios tested produced much larger droplet sizes. Operational spray mixes tended to slightly increase the potential for spray drift compared with the water control. The CP-09, 0.078, 30° nozzle used at 45° met the operational droplet size specification but is more sensitive to changes to nozzle angle (0° versus 45°) than the other nozzles tested. None of the three Accu-FloTM nozzles tested met the target droplet size specification. However, the Accu-FloTM nozzles produced very few fine droplets making them good choices for reducing spray drift potential.
{"title":"Meeting droplet size specifications for aerial herbicide application to control wilding conifers","authors":"B. Richardson, C. Rolando, A. Hewitt, M. Kimberley","doi":"10.30843/nzpp.2020.73.11712","DOIUrl":"https://doi.org/10.30843/nzpp.2020.73.11712","url":null,"abstract":"Large areas of New Zealand are being aerially sprayed with herbicides to manage ‘wilding’ conifer spread. The purpose of the study was to obtain and analyse droplet spectra produced by nozzles commonly used for wilding conifer spraying to determine whether or not operational recommendations for a target droplet size class (~350 μm) are being met. Droplet spectra were measured in a wind tunnel for 27 nozzle × 3 operating condition (nozzle angle, air speed and pressure) combinations tested for each of three spray mixes. AGDISP, an aerial spray application simulation model, was used to quantify the field performance implications of changes to droplet spectra parameters. Only one nozzle, the CP-09, 0.078, 30°, met the target droplet size specification when used at 45° but not at 0°. However, under these conditions, this nozzle produced a large driftable fraction. All but one of the other scenarios tested produced much larger droplet sizes. Operational spray mixes tended to slightly increase the potential for spray drift compared with the water control. The CP-09, 0.078, 30° nozzle used at 45° met the operational droplet size specification but is more sensitive to changes to nozzle angle (0° versus 45°) than the other nozzles tested. None of the three Accu-FloTM nozzles tested met the target droplet size specification. However, the Accu-FloTM nozzles produced very few fine droplets making them good choices for reducing spray drift potential.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"42 1","pages":"13-23"},"PeriodicalIF":0.0,"publicationDate":"2020-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86839133","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 : 2020-01-27DOI: 10.30843/nzpp.2020.73.11012
Amy Maslen-Miller, R. A. Fullerton, Angelika Tugaga, Fa'alelei Tunupopo, S. Molimau-Samasoni, J. K. Bowen, R. MacDiarmid, J. Tyson
Taro leaf blight (TLB), caused by Phytophthora colocasiae, is normally characterised by leaf lesions. There are isolated reports of P. colocasiae causing a corm rot but the symptoms are not well defined and have not been recorded in Samoa. Here we report on an inoculation method and describe the symptoms of corm rot caused by P. colocasiae. In this study, a corm inoculation method was developed in physical containment laboratories in New Zealand and subsequent symptom development studies were undertaken on TLB-tolerant taro cultivars in Apia, Samoa. The Samoan TLB-tolerant taro cultivars were able to be wound-infected with P. colocasiae and the results confirm previous descriptions of P. colocasiae infection giving rise to light brown firm rots in corms. This work has allowed the pictorial record of corm rots to be updated, potentially providing for better distinction between corm rots caused by P. colocasiae and those caused by other pathogens, such as Fusarium spp.
{"title":"Symptom expression of Phytophthora colocasiae in inoculated taro corms","authors":"Amy Maslen-Miller, R. A. Fullerton, Angelika Tugaga, Fa'alelei Tunupopo, S. Molimau-Samasoni, J. K. Bowen, R. MacDiarmid, J. Tyson","doi":"10.30843/nzpp.2020.73.11012","DOIUrl":"https://doi.org/10.30843/nzpp.2020.73.11012","url":null,"abstract":"Taro leaf blight (TLB), caused by Phytophthora colocasiae, is normally characterised by leaf lesions. There are isolated reports of P. colocasiae causing a corm rot but the symptoms are not well defined and have not been recorded in Samoa. Here we report on an inoculation method and describe the symptoms of corm rot caused by P. colocasiae. In this study, a corm inoculation method was developed in physical containment laboratories in New Zealand and subsequent symptom development studies were undertaken on TLB-tolerant taro cultivars in Apia, Samoa. The Samoan TLB-tolerant taro cultivars were able to be wound-infected with P. colocasiae and the results confirm previous descriptions of P. colocasiae infection giving rise to light brown firm rots in corms. This work has allowed the pictorial record of corm rots to be updated, potentially providing for better distinction between corm rots caused by P. colocasiae and those caused by other pathogens, such as Fusarium spp.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"32 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84752388","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 : 2020-01-01DOI: 10.30843/nzpp.2020.73.11717
J. Tyson, M. Manning, P. Wright
Ceratocystis fimbriata was reported in 2010 causing wilt and death of kiwifruit (Actinidia spp.) vines in Brazil, with losses of up to 50% of vines on some orchards. New Zealand is one of the largest producers of kiwifruit in the world, but C. fimbriata has been recorded only on kūmara (Ipomoea batatas) in this country. In this study the pathogenicity of New Zealand isolates of C. fimbriata from kūmara was examined using potted vines of four kiwifruit cultivars. During the trial, none of the vines became visibly diseased, growth rates were not restricted, and discolouration at the inoculation sites on the stem was minimal. In comparison, tests by researchers in Brazil using C. fimbriata isolated from symptomatic kiwifruit resulted in lengthy lesions and death of susceptible kiwifruit seedlings. Sequences of the internal transcribed spacer (ITS) region of rRNA from the New Zealand C. fimbriata isolates were 100% identical to those sequences from C. fimbriata isolates from Ipomoea batatas in GenBank. This study has shown that the New Zealand isolates of C. fimbriata from kūmara are not pathogenic to the kiwifruit cultivars tested, and are a different pathotype to those found on kiwifruit in Brazil.
{"title":"Pathogenicity of Ceratocystis fimbriata from New Zealand kūmara on kiwifruit cultivars","authors":"J. Tyson, M. Manning, P. Wright","doi":"10.30843/nzpp.2020.73.11717","DOIUrl":"https://doi.org/10.30843/nzpp.2020.73.11717","url":null,"abstract":"Ceratocystis fimbriata was reported in 2010 causing wilt and death of kiwifruit (Actinidia spp.) vines in Brazil, with losses of up to 50% of vines on some orchards. New Zealand is one of the largest producers of kiwifruit in the world, but C. fimbriata has been recorded only on kūmara (Ipomoea batatas) in this country. In this study the pathogenicity of New Zealand isolates of C. fimbriata from kūmara was examined using potted vines of four kiwifruit cultivars. During the trial, none of the vines became visibly diseased, growth rates were not restricted, and discolouration at the inoculation sites on the stem was minimal. In comparison, tests by researchers in Brazil using C. fimbriata isolated from symptomatic kiwifruit resulted in lengthy lesions and death of susceptible kiwifruit seedlings. Sequences of the internal transcribed spacer (ITS) region of rRNA from the New Zealand C. fimbriata isolates were 100% identical to those sequences from C. fimbriata isolates from Ipomoea batatas in GenBank. This study has shown that the New Zealand isolates of C. fimbriata from kūmara are not pathogenic to the kiwifruit cultivars tested, and are a different pathotype to those found on kiwifruit in Brazil.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"609 1","pages":"6-12"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77013886","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}
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