Pub Date : 2019-07-27DOI: 10.30843/NZPP.2019.72.266
G. N. Hill, P. Jaksons, J. Sharp, A. Hunt, K. Lewis
Botrytis cinerea causes botrytis bunch rot (BBR) disease in wine grapes. Small-scale labour-intensive visual disease assessments may not adequately represent an entire vineyard but larger assessments add cost without necessarily improving accuracy or financial returns. BBR-severity data were collected on three dates from two sites and spatially interpolated. Balanced acceptance sampling (BAS) and simple random sampling (SRS) were compared using sample sizes of 2 to 200 vines. Assessment times were calculated for both walking (rows ignored) and driving (rows impassable) and costs compared with assessment error and effects on crop value. Overall, BAS performed better than SRS. Driving was faster than walking except when sample distribution necessitated travelling down every row regardless of sample size. Annual crop losses of up to NZ$2578 per hectare could result from short assessment times and subsequent inaccurate estimates of BBR severity. Spatial interpolation was shown to be a useful and promising technique for studying BBR sampling strategies in vineyard blocks. Travel was not a substantial component of assessment time. An 80-minute-long assessment could substantially reduce economic losses because of errors in BBR assessments.
{"title":"Investigating time and economic costs of botrytis bunch rot sampling using interpolated data","authors":"G. N. Hill, P. Jaksons, J. Sharp, A. Hunt, K. Lewis","doi":"10.30843/NZPP.2019.72.266","DOIUrl":"https://doi.org/10.30843/NZPP.2019.72.266","url":null,"abstract":"Botrytis cinerea causes botrytis bunch rot (BBR) disease in wine grapes. Small-scale labour-intensive visual disease assessments may not adequately represent an entire vineyard but larger assessments add cost without necessarily improving accuracy or financial returns. BBR-severity data were collected on three dates from two sites and spatially interpolated. Balanced acceptance sampling (BAS) and simple random sampling (SRS) were compared using sample sizes of 2 to 200 vines. Assessment times were calculated for both walking (rows ignored) and driving (rows impassable) and costs compared with assessment error and effects on crop value. Overall, BAS performed better than SRS. Driving was faster than walking except when sample distribution necessitated travelling down every row regardless of sample size. Annual crop losses of up to NZ$2578 per hectare could result from short assessment times and subsequent inaccurate estimates of BBR severity. Spatial interpolation was shown to be a useful and promising technique for studying BBR sampling strategies in vineyard blocks. Travel was not a substantial component of assessment time. An 80-minute-long assessment could substantially reduce economic losses because of errors in BBR assessments.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85729446","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 : 2019-07-27DOI: 10.30843/NZPP.2019.72.248
M. Kanjanamaneesathian, W. Nimanong
The bacterium Bacillus megaterium can be used to biologically control sheath blight and grain discoloration in rice. Large-scale inoculations using liquid cultures are cumbersome so the efficacy of an alternative, paper-based system was examined. Bacterial endospores were embedded on filter papers and multiplied using a simple culture technique. The resulting suspension was used to pre-soak yardlong bean and cucumber seeds before sowing to assess its effect on seed germination and weight. The efficacy of the bacterium in protecting cucumber seeds from pre-emergent damping-off was also examined. The population of bacteria embedded in paper declined initially but remained stable for 150 days at room temperature. Bacterial culture reduced seed germination of cucumber and seedling weight of yardlong beans. Dilution with water either increased or reduced germination of cucumber seeds depending on concentration. A 1:10 v/v dilution increased cucumber-seed germination in a pre-emergent damping-off pot test but all seedlings later died, irrespective of treatment. Paper-based inoculum has the potential to replace liquid inoculum but further work is required to optimise the concentrations of the bacterial culture to achieve disease control without adversely affecting the host plant.
{"title":"Paper-based inoculum of Bacillus megaterium and its practical application for simple culture preparation","authors":"M. Kanjanamaneesathian, W. Nimanong","doi":"10.30843/NZPP.2019.72.248","DOIUrl":"https://doi.org/10.30843/NZPP.2019.72.248","url":null,"abstract":"The bacterium Bacillus megaterium can be used to biologically control sheath blight and grain discoloration in rice. Large-scale inoculations using liquid cultures are cumbersome so the efficacy of an alternative, paper-based system was examined. Bacterial endospores were embedded on filter papers and multiplied using a simple culture technique. The resulting suspension was used to pre-soak yardlong bean and cucumber seeds before sowing to assess its effect on seed germination and weight. The efficacy of the bacterium in protecting cucumber seeds from pre-emergent damping-off was also examined. The population of bacteria embedded in paper declined initially but remained stable for 150 days at room temperature. Bacterial culture reduced seed germination of cucumber and seedling weight of yardlong beans. Dilution with water either increased or reduced germination of cucumber seeds depending on concentration. A 1:10 v/v dilution increased cucumber-seed germination in a pre-emergent damping-off pot test but all seedlings later died, irrespective of treatment. Paper-based inoculum has the potential to replace liquid inoculum but further work is required to optimise the concentrations of the bacterial culture to achieve disease control without adversely affecting the host plant.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"57 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80435421","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 : 2019-07-27DOI: 10.30843/NZPP.2019.72.259
C. Henderson, M. Cripps, S. Casonato
Cirsium arvense (Californian thistle) is a problematic weed in agricultural systems throughout New Zealand and the rust fungus Puccinia punctiformis is a potential biological control agent for this weed. Puccinia punctiformis can systemically infect thistles but the movement of the pathogen in planta is not fully understood. This research determined the level of infection in planta caused by P. punctiformis at a single time point. The concentration of P. punctiformis DNA in planta was determined to ascertain the location of the fungus within naturally field-infected C. arvense. Quantitative polymerase chain reaction was undertaken on above-ground symptomatic and asymptomatic C. arvense tissue at various locations within leaves (top, middle and bottom) and the main stem. All C. arvense shoots had detectable amounts of P. punctiformis but the concentration was 100× greater in symptomatic compared with asymptomatic shoots. In general, the concentration of fungus progressed up the leaves with a significant effect between locations (P<0.001). Puccinia punctiformis was found in planta but broadscale disease of C. arvense does not occur and the reason for this is unknown.
{"title":"Distribution of Puccinia punctiformis in above-ground tissue of Cirsium arvense (Californian thistle)","authors":"C. Henderson, M. Cripps, S. Casonato","doi":"10.30843/NZPP.2019.72.259","DOIUrl":"https://doi.org/10.30843/NZPP.2019.72.259","url":null,"abstract":"Cirsium arvense (Californian thistle) is a problematic weed in agricultural systems throughout New Zealand and the rust fungus Puccinia punctiformis is a potential biological control agent for this weed. Puccinia punctiformis can systemically infect thistles but the movement of the pathogen in planta is not fully understood. This research determined the level of infection in planta caused by P. punctiformis at a single time point. The concentration of P. punctiformis DNA in planta was determined to ascertain the location of the fungus within naturally field-infected C. arvense. Quantitative polymerase chain reaction was undertaken on above-ground symptomatic and asymptomatic C. arvense tissue at various locations within leaves (top, middle and bottom) and the main stem. All C. arvense shoots had detectable amounts of P. punctiformis but the concentration was 100× greater in symptomatic compared with asymptomatic shoots. In general, the concentration of fungus progressed up the leaves with a significant effect between locations (P<0.001). Puccinia punctiformis was found in planta but broadscale disease of C. arvense does not occur and the reason for this is unknown.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73385387","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 : 2019-07-27DOI: 10.30843/NZPP.2019.72.258
Q. Paynter, P. Peterson, S. Cranwell, C. Winks, Zane McGrath
The broom leaf beetle (Gonioctena olivacea) and the Honshu white admiral butterfly (Limenitis glorifica) have been introduced into New Zealand as biocontrol agents of the weeds Scotch broom (Cytisus scoparius) and Japanese honeysuckle (Lonicera japonica) respectively. However, neither agent has been successful yet. Larval predation of these species could be a factor affecting their success, and this hypothesis was tested using various predator-exclusion treatments. Survival of broom leaf beetle larvae increased c. five-fold by sleeving Scotch broom seedlings in fine mesh. In contrast, survival was unaffected by excluding either crawling predators using sticky barriers or larger predators using chicken wire. Survival of Honshu white admiral butterfly larvae increased c. ten-fold by excluding either crawling predators using sticky barriers or flying predators using a fine-mesh sleeve. Simultaneously excluding both crawling and flying predators resulted in a c. 23-fold increase in survival. These results suggest that larval predation could be limiting the populations of both broom leaf beetle and Honshu white admiral. Future biocontrol programmes could prioritise candidate agents accordingly.
{"title":"Impact of generalist predation on two weed biocontrol agents in New Zealand","authors":"Q. Paynter, P. Peterson, S. Cranwell, C. Winks, Zane McGrath","doi":"10.30843/NZPP.2019.72.258","DOIUrl":"https://doi.org/10.30843/NZPP.2019.72.258","url":null,"abstract":"The broom leaf beetle (Gonioctena olivacea) and the Honshu white admiral butterfly (Limenitis glorifica) have been introduced into New Zealand as biocontrol agents of the weeds Scotch broom (Cytisus scoparius) and Japanese honeysuckle (Lonicera japonica) respectively. However, neither agent has been successful yet. Larval predation of these species could be a factor affecting their success, and this hypothesis was tested using various predator-exclusion treatments. Survival of broom leaf beetle larvae increased c. five-fold by sleeving Scotch broom seedlings in fine mesh. In contrast, survival was unaffected by excluding either crawling predators using sticky barriers or larger predators using chicken wire. Survival of Honshu white admiral butterfly larvae increased c. ten-fold by excluding either crawling predators using sticky barriers or flying predators using a fine-mesh sleeve. Simultaneously excluding both crawling and flying predators resulted in a c. 23-fold increase in survival. These results suggest that larval predation could be limiting the populations of both broom leaf beetle and Honshu white admiral. Future biocontrol programmes could prioritise candidate agents accordingly.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"43 1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72544430","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 : 2019-07-27DOI: 10.30843/NZPP.2019.72.308
J. Drummond, R. Chapman
Resistance of sawtoothed grain beetle (Oryzaephilus surinamensis) to organophosphate insecticides is documented internationally. There are anecdotal reports of reduced efficacy in New Zealand but to date no empirical assessments have been made. Two-laboratory-based test methods using either a dust (Actellic® Dust) or liquid (Actellic® 50EC) formulations of pirimiphos-methyl, were compared to determine the response of five Canterbury sawtoothed grain beetle populations. A mini-silo method employed grain treated with the recommended application rate (200 g a.i./tonne seed) of pirimiphos-methyl dust. A Petri-dish method treated internal surfaces of 50-mm diameter Petri dishes with liquid pirimiphos-methyl at concentrations from 0–0.1 g a.i./L to determine an estimated LC50 (lethal concentration for 50% mortality) for each population. The rank order of mortality (highest to lowest) in the mini-silo test was similar to the Petri-dish LC50 rankings for the five populations tested. The results illustrate variation in responses to pirimiphosmethyl concentrations by sawtoothed grain beetle populations, indicating both methods are potential options for future resistance testing and will aid the development of management strategies for control of stored insect pests.
国际上已有文献报道锯齿谷甲虫(Oryzaephilus surinamensis)对有机磷杀虫剂的抗性。有传闻说新西兰的疗效下降，但迄今为止还没有进行实证评估。采用粉尘(Actellic®dust)或液体(Actellic®50EC)配方的两种基于实验室的测试方法进行比较，以确定五种坎特伯雷锯齿谷物甲虫种群的反应。采用小仓法，稻谷采用推荐施用量(200克a.i./吨稻谷)处理的稻谷。采用皮氏培养皿法，用浓度为0-0.1 g a.i./L的甲基腈磷液体处理直径为50 mm的皮氏培养皿的内表面，以确定每个种群的估计LC50(50%死亡率的致死浓度)。在小筒仓试验中，死亡率的等级顺序(从高到低)与培养皿LC50排名相似。结果表明，锯齿谷甲虫种群对吡磷甲酯浓度的反应存在差异，表明这两种方法都是未来抗性测试的潜在选择，并将有助于制定储存性害虫控制管理策略。
{"title":"A comparison of two methods to determine the susceptibility of sawtoothed grain beetle (Oryzaephilus surinamensis) populations to pirimiphos-methyl from Canterbury, New Zealand","authors":"J. Drummond, R. Chapman","doi":"10.30843/NZPP.2019.72.308","DOIUrl":"https://doi.org/10.30843/NZPP.2019.72.308","url":null,"abstract":"Resistance of sawtoothed grain beetle (Oryzaephilus surinamensis) to organophosphate insecticides is documented internationally. There are anecdotal reports of reduced efficacy in New Zealand but to date no empirical assessments have been made. Two-laboratory-based test methods using either a dust (Actellic® Dust) or liquid (Actellic® 50EC) formulations of pirimiphos-methyl, were compared to determine the response of five Canterbury sawtoothed grain beetle populations. A mini-silo method employed grain treated with the recommended application rate (200 g a.i./tonne seed) of pirimiphos-methyl dust. A Petri-dish method treated internal surfaces of 50-mm diameter Petri dishes with liquid pirimiphos-methyl at concentrations from 0–0.1 g a.i./L to determine an estimated LC50 (lethal concentration for 50% mortality) for each population. The rank order of mortality (highest to lowest) in the mini-silo test was similar to the Petri-dish LC50 rankings for the five populations tested. The results illustrate variation in responses to pirimiphosmethyl concentrations by sawtoothed grain beetle populations, indicating both methods are potential options for future resistance testing and will aid the development of management strategies for control of stored insect pests.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"09 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90490858","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 : 2019-07-27DOI: 10.30843/NZPP.2019.72.271
A. Umar, D. Kandula, J. Hampton, M. Rolston, S. Chng
Perennial ryegrass (Lolium perenne) is the major pasture grass in New Zealand but is highly susceptible to take-all disease, caused by the root-rot pathogen Gaeumannomyces graminis (Gg). Isolates of the fungus Trichoderma atroviride are known to control Gg but it is not known if a mixture of isolates would be more effective than individual ones. Soil from a field naturally infested with Gg was placed in containers in a glasshouse and sown with ryegrass seeds then treated with one of three Trichoderma atroviride isolates or a mixture of all three isolates. All T. atroviride treatments significantly increased shoot dry matter by 46–73% and root dry matter by 42–62% compared with the control but a mixture of isolates was no more effective than individual isolates. Application of T. atroviride also significantly decreased root disease severity, which was negatively correlated with root dry matter. Takeall in pastures could possibly be controlled by overdrilling grass with a single isolate of T. atroviride.
{"title":"Potential biological control of take-all disease in perennial ryegrass","authors":"A. Umar, D. Kandula, J. Hampton, M. Rolston, S. Chng","doi":"10.30843/NZPP.2019.72.271","DOIUrl":"https://doi.org/10.30843/NZPP.2019.72.271","url":null,"abstract":"Perennial ryegrass (Lolium perenne) is the major pasture grass in New Zealand but is highly susceptible to take-all disease, caused by the root-rot pathogen Gaeumannomyces graminis (Gg). Isolates of the fungus Trichoderma atroviride are known to control Gg but it is not known if a mixture of isolates would be more effective than individual ones. Soil from a field naturally infested with Gg was placed in containers in a glasshouse and sown with ryegrass seeds then treated with one of three Trichoderma atroviride isolates or a mixture of all three isolates. All T. atroviride treatments significantly increased shoot dry matter by 46–73% and root dry matter by 42–62% compared with the control but a mixture of isolates was no more effective than individual isolates. Application of T. atroviride also significantly decreased root disease severity, which was negatively correlated with root dry matter. Takeall in pastures could possibly be controlled by overdrilling grass with a single isolate of T. atroviride.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"41 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87533138","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 : 2019-07-27DOI: 10.30843/NZPP.2019.72.288
S. Casonato
Recently, fruit drop in two green varieties of kiwifruit (Actinidia deliciosa; VarA and VarB) has increased towards the harvest date. The efficacy of two biofungicides, applied post-flowering, to ameliorate the effects of early fruit drop in VarA and VarB during the 2017–18 growing season was tested. Treatments were applied to a single bay, with buffer bays and rows adjacent. Treatments were two different Bacillus-based biofungicide products; Serenade® Max (a.i. B. subtilis QST713 strain) and Triple-X® (a.i. B. amyloliquefaciens BS 1b). There was an untreated control. All fruits in the canopy, within the treated bay, were counted and recorded at 4-weekly intervals, over 5 months until harvest. At the VarA site, there was no statistical difference (P>0.1) in the percentage of fruit drop between the control (7%), Triple-X® (5%) and Serenade® Max (10%) treated vines. At the VarB site, fruit drop differed statistically (P<0.1) between Triple-X® treated vines (5%) and the control (10.5%), with Serenade® Max treated vines (6.5%) having intermediate fruit drop. The use of Triple-X® may be an option to assist with reducing fruit drop in kiwifruit.
{"title":"Fruit drop in two kiwifruit varieties and the use of two Bacillus-based biofungicides","authors":"S. Casonato","doi":"10.30843/NZPP.2019.72.288","DOIUrl":"https://doi.org/10.30843/NZPP.2019.72.288","url":null,"abstract":"Recently, fruit drop in two green varieties of kiwifruit (Actinidia deliciosa; VarA and VarB) has increased towards the harvest date. The efficacy of two biofungicides, applied post-flowering, to ameliorate the effects of early fruit drop in VarA and VarB during the 2017–18 growing season was tested. Treatments were applied to a single bay, with buffer bays and rows adjacent. Treatments were two different Bacillus-based biofungicide products; Serenade® Max (a.i. B. subtilis QST713 strain) and Triple-X® (a.i. B. amyloliquefaciens BS 1b). There was an untreated control. All fruits in the canopy, within the treated bay, were counted and recorded at 4-weekly intervals, over 5 months until harvest. At the VarA site, there was no statistical difference (P>0.1) in the percentage of fruit drop between the control (7%), Triple-X® (5%) and Serenade® Max (10%) treated vines. At the VarB site, fruit drop differed statistically (P<0.1) between Triple-X® treated vines (5%) and the control (10.5%), with Serenade® Max treated vines (6.5%) having intermediate fruit drop. The use of Triple-X® may be an option to assist with reducing fruit drop in kiwifruit.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88818448","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 : 2019-07-26DOI: 10.30843/NZPP.2019.72.268
J. Tyson, M. Manning, K. Everett, R. A. Fullerton
Neofabraea actinidiae (syn. Cryptosporiopsis actinidiae) is a member of a suite of fungi associated with ‘ripe rots’ of kiwifruit. Although it has been recorded regularly from kiwifruit in New Zealand over the past 30-40 years, initially as ‘Cryptosporiopsis sp.’, there is a general lack of knowledge of this fungus. This paper provides a review of the current records and available literature on the taxonomy and biology of the organism, and assesses the knowledge gaps in the disease cycle and epidemiology of N. actinidiae in kiwifruit orchards. The conidia of the fungus are likely to be water borne, infect fruit during or near to flowering and remain latent until harvest and subsequent ripening. The source of inoculum remains unknown. This review may stimulate new research into this pathogen and give insights into potential control strategies.
{"title":"Neofabraea actinidiae in New Zealand kiwifruit orchards: current status and knowledge gaps","authors":"J. Tyson, M. Manning, K. Everett, R. A. Fullerton","doi":"10.30843/NZPP.2019.72.268","DOIUrl":"https://doi.org/10.30843/NZPP.2019.72.268","url":null,"abstract":"Neofabraea actinidiae (syn. Cryptosporiopsis actinidiae) is a member of a suite of fungi associated with ‘ripe rots’ of kiwifruit. Although it has been recorded regularly from kiwifruit in New Zealand over the past 30-40 years, initially as ‘Cryptosporiopsis sp.’, there is a general lack of knowledge of this fungus. This paper provides a review of the current records and available literature on the taxonomy and biology of the organism, and assesses the knowledge gaps in the disease cycle and epidemiology of N. actinidiae in kiwifruit orchards. The conidia of the fungus are likely to be water borne, infect fruit during or near to flowering and remain latent until harvest and subsequent ripening. The source of inoculum remains unknown. This review may stimulate new research into this pathogen and give insights into potential control strategies.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"77 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82835048","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 : 2019-07-26DOI: 10.30843/NZPP.2019.72.279
Jason T. Smith, M. Walter, R. Campbell, L. Turner
European canker, Neonectria ditissima, is a worldwide apple tree disease killing shoots, branches and trees, and treatment with phosphorous acid is a possible control option. The effect of six postharvest phosphorous acid (PA) treatments on fruit residues the following season was studied in Tasman on two trial sites growing ‘Scifresh’ or ‘Scilate’ apple trees. Spray treatments consisted of number (0–3) and timing (early, mid and/or late) of PA applications. Additionally, leaf-scar wounds were artificially inoculated with N. ditissima spores at the ‘Scilate’ site on 1 and 8 June 2017 to determine disease control. Symptom expression was checked regularly between October 2017 and February 2018. None of the treatments caused a statistically significant reduction in the incidence of canker development compared with the control. Two or more PA applications resulted in PA residues in fruit, at harvest, the following season. Higher PA residues were found in fruit following early applications than with late applications. More applications of PA resulted in higher residues. This finding has important implications for exporting fruit to markets that have no tolerance for PA residues.
{"title":"Can phosphorous acid be used to control Neonectria ditissima in New Zealand grown apples?","authors":"Jason T. Smith, M. Walter, R. Campbell, L. Turner","doi":"10.30843/NZPP.2019.72.279","DOIUrl":"https://doi.org/10.30843/NZPP.2019.72.279","url":null,"abstract":"European canker, Neonectria ditissima, is a worldwide apple tree disease killing shoots, branches and trees, and treatment with phosphorous acid is a possible control option. The effect of six postharvest phosphorous acid (PA) treatments on fruit residues the following season was studied in Tasman on two trial sites growing ‘Scifresh’ or ‘Scilate’ apple trees. Spray treatments consisted of number (0–3) and timing (early, mid and/or late) of PA applications. Additionally, leaf-scar wounds were artificially inoculated with N. ditissima spores at the ‘Scilate’ site on 1 and 8 June 2017 to determine disease control. Symptom expression was checked regularly between October 2017 and February 2018. None of the treatments caused a statistically significant reduction in the incidence of canker development compared with the control. Two or more PA applications resulted in PA residues in fruit, at harvest, the following season. Higher PA residues were found in fruit following early applications than with late applications. More applications of PA resulted in higher residues. This finding has important implications for exporting fruit to markets that have no tolerance for PA residues.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82292517","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 : 2019-07-26DOI: 10.30843/NZPP.2019.72.313
Fa'alelei Tunupopo, Fai'ilagi Sa'ili, L. Jamieson, Samuel D. J. Brown
Of the seven species of Bactrocera fruit flies found in Samoa, only two (B. kirki (Froggatt) and B. xanthodes (Broun)) are of economic importance. These species attack a range of fruit, including papaya (Carica papaya), breadfruit (Artocarpus altilis), eggplants (Solanum melongena) and citrus. The presence of these two species limits export market access for Samoan produce. Eggplants and breadfruit infested with the eggs of B. kirki and B. xanthodes, respectively, were treated using a high-temperature forced-air (HTFA) protocol to heat the fruits to core temperatures of 40oC, 42oC, 44oC or 46oC. No B. xanthodes pupae emerged from fruit treated at 42oC or greater. Pupae of B. kirki were found from fruit treated at temperatures up to 44oC, but failed to survive treatments at 46oC. The HTFA protocol previously approved for treatment of other Pacific fruit flies (fruit core temperature to 47.2oC for 20 min) works without modification for treatment of the two combinations of fruit flies and commodities tested. However, less intense HTFA treatments are worth investigating, if required to enhance fruit quality.
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