Pub Date : 2022-09-21DOI: 10.30843/nzpp.2022.75.11760
C. Buddenhagen, Ben P. Harvey, Ben Wynne-Jones, D. Hackell, H. Ghanizadeh, Yuichi Ando, Zachary Ngow, T. James
The prevalence of herbicide resistance in ryegrass (Lolium spp.) in the wine-growing regions in New Zealand is poorly understood. Cases of glyphosate, glufosinate and amitrole-resistant ryegrass were documented in a few vineyards in New Zealand in 2013, but there have been no regional surveys for resistance. To address this knowledge gap, 106 vineyards were visited across the important New Zealand wine-growing regions of Marlborough and Waipara in late February 2021, and Hawke’s Bay and Gisborne in late February 2022, and seed samples from individual plants at each site surviving weed-control measures were collected. Ryegrass was found in more South Island (68%) than North Island (20%) vineyards. These seeds, and those from a susceptible ryegrass population were sown in marked rows into trays (10-20 seeds per herbicide) and grown in a glasshouse. When seedlings reached the 3-4 leaf stage, trays were sprayed at the highest recommended label rate of glyphosate. Samples with enough seed were also screened against additional herbicides, amitrole, glufosinate or clethodim. The results indicated 39% of the surveyed vineyards contained glyphosate-resistant ryegrass, with cases detected across all regions, including 58% of vineyards in Marlborough. Eleven of the 27 Marlborough vineyards screened contained amitrole-resistant ryegrass; six samples were also resistant to glyphosate. However, glufosinate and clethodim were still effective against ryegrass at the sites tested. Considering the levels of herbicide resistance to ryegrass observed in this study, growers should explore alternative weed-suppression measures, including tilling, cover-crops, grazing, mowing and the use of herbicides with different modes of action.
{"title":"Ryegrass resistance to glyphosate and amitrole is becoming common in New Zealand vineyards","authors":"C. Buddenhagen, Ben P. Harvey, Ben Wynne-Jones, D. Hackell, H. Ghanizadeh, Yuichi Ando, Zachary Ngow, T. James","doi":"10.30843/nzpp.2022.75.11760","DOIUrl":"https://doi.org/10.30843/nzpp.2022.75.11760","url":null,"abstract":"The prevalence of herbicide resistance in ryegrass (Lolium spp.) in the wine-growing regions in New Zealand is poorly understood. Cases of glyphosate, glufosinate and amitrole-resistant ryegrass were documented in a few vineyards in New Zealand in 2013, but there have been no regional surveys for resistance. To address this knowledge gap, 106 vineyards were visited across the important New Zealand wine-growing regions of Marlborough and Waipara in late February 2021, and Hawke’s Bay and Gisborne in late February 2022, and seed samples from individual plants at each site surviving weed-control measures were collected. Ryegrass was found in more South Island (68%) than North Island (20%) vineyards. These seeds, and those from a susceptible ryegrass population were sown in marked rows into trays (10-20 seeds per herbicide) and grown in a glasshouse. When seedlings reached the 3-4 leaf stage, trays were sprayed at the highest recommended label rate of glyphosate. Samples with enough seed were also screened against additional herbicides, amitrole, glufosinate or clethodim. The results indicated 39% of the surveyed vineyards contained glyphosate-resistant ryegrass, with cases detected across all regions, including 58% of vineyards in Marlborough. Eleven of the 27 Marlborough vineyards screened contained amitrole-resistant ryegrass; six samples were also resistant to glyphosate. However, glufosinate and clethodim were still effective against ryegrass at the sites tested. Considering the levels of herbicide resistance to ryegrass observed in this study, growers should explore alternative weed-suppression measures, including tilling, cover-crops, grazing, mowing and the use of herbicides with different modes of action.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78693571","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 : 2022-09-20DOI: 10.30843/nzpp.2022.75.11756
P. Gerard, Ela Hiszczyńska-Sawicka
Perennial ryegrass (Lolium perenne L.) grows in association with a fungal endophyte Epichloe festucae var. lolii (Latch, Christensen & Samuels) Bacon & Schardl, which produces alkaloids that protect the grass against grazing by mammals and insects. These alkaloids are found in guttation fluid (xylem sap exuded from leaves through special structures known as hydathodes) and have the potential to impact on beneficial invertebrates in pastoral ecosystems. Newly emerged adults of the parasitoid Microctonus aethiopoides Loan (Hymenoptera: Braconidae) were supplied with guttation fluid from pot-grown ryegrasses infected with three different strains of endophyte (standard, AR37, AR1) or no endophyte collected at different times of the year, or water, sucrose solution or no liquid. Longevity was compared when individuals were held in separate vials in controlled environment room at 20oC with 16:8 h light:dark photoperiod. An enzymatic method was used to measure sugars in guttation fluid samples collected on three dates. Guttation fluid from endophyte-infected grasses was found to have no detrimental effect on M. aethiopoides longevity and to contain glucose and fructose. Guttation fluid from AR37-infected ryegrass collected in autumn increased insect longevity compared to water and fluid from standard-type infected ryegrass by 26% and 24% respectively. The lack of available food sources in New Zealand ryegrass-dominant pastures means that guttation fluid from AR37-infected ryegrass in autumn may contribute to M. aethiopoides efficacy as a biocontrol agent through enhanced longevity.
{"title":"Impact of guttation fluid from perennial ryegrass infected with different strains of Epichloe festucae var. lolii endophyte on Microctonus aethiopoides adult longevity","authors":"P. Gerard, Ela Hiszczyńska-Sawicka","doi":"10.30843/nzpp.2022.75.11756","DOIUrl":"https://doi.org/10.30843/nzpp.2022.75.11756","url":null,"abstract":"Perennial ryegrass (Lolium perenne L.) grows in association with a fungal endophyte Epichloe festucae var. lolii (Latch, Christensen & Samuels) Bacon & Schardl, which produces alkaloids that protect the grass against grazing by mammals and insects. These alkaloids are found in guttation fluid (xylem sap exuded from leaves through special structures known as hydathodes) and have the potential to impact on beneficial invertebrates in pastoral ecosystems. Newly emerged adults of the parasitoid Microctonus aethiopoides Loan (Hymenoptera: Braconidae) were supplied with guttation fluid from pot-grown ryegrasses infected with three different strains of endophyte (standard, AR37, AR1) or no endophyte collected at different times of the year, or water, sucrose solution or no liquid. Longevity was compared when individuals were held in separate vials in controlled environment room at 20oC with 16:8 h light:dark photoperiod. An enzymatic method was used to measure sugars in guttation fluid samples collected on three dates. Guttation fluid from endophyte-infected grasses was found to have no detrimental effect on M. aethiopoides longevity and to contain glucose and fructose. Guttation fluid from AR37-infected ryegrass collected in autumn increased insect longevity compared to water and fluid from standard-type infected ryegrass by 26% and 24% respectively. The lack of available food sources in New Zealand ryegrass-dominant pastures means that guttation fluid from AR37-infected ryegrass in autumn may contribute to M. aethiopoides efficacy as a biocontrol agent through enhanced longevity.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89367617","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 : 2022-08-30DOI: 10.30843/nzpp.2022.75.11761
P. Wright, R. Frampton, C. Anderson, D. Hedderley
Soils in which disease fails to develop despite pathogen presence are considered disease-suppressive. They offer sustainable, effective protection to plants against infection by soil-borne pathogens. Naturally disease-suppressive soils have been reported for diseases of a diverse range of agricultural crops worldwide yet the underlying mechanisms of disease suppression are still not completely understood. Two large greenhouse experiments, conducted during 2017/18 (Year 1) and 2018/19 (Year 2), determined that soils naturally suppressive to stem canker and black scurf of potato (caused by Rhizoctonia solani) are present in vegetable-arable cropping soils of the Auckland and Waikato regions of New Zealand. Soil was pre-treated with heat prior to inoculation with R. solani and compared with untreated and uninoculated controls to ascertain if stem canker and black scurf suppression was ‘general’, or ‘specific’ (i.e. transferable; possibly involving specific microorganisms). Rhizoctonia solani inoculation was also combined with transfer of one part test soil to nine parts of a known disease-conducive soil. Abiotic factors such as soil texture and organic matter content influenced black scurf incidence and severity. Soil microorganisms were also involved in disease suppression since black scurf incidence and severity markedly increased when they were eliminated or reduced by soil heat pre-treatment. Microbial profiling of the soils through sequencing revealed that taxa of geographically close soils of the same type had similar fungal and bacterial community structure and diversity even though they differed in their capacity to suppress black scurf. These results suggest that although the soil microbiome as a whole, was mainly responsible for soil disease suppressiveness, certain bacterial genera or species may play a role in black scurf suppression.
{"title":"Factors associated with soils suppressive to black scurf of potato caused by Rhizoctonia solani","authors":"P. Wright, R. Frampton, C. Anderson, D. Hedderley","doi":"10.30843/nzpp.2022.75.11761","DOIUrl":"https://doi.org/10.30843/nzpp.2022.75.11761","url":null,"abstract":"Soils in which disease fails to develop despite pathogen presence are considered disease-suppressive. They offer sustainable, effective protection to plants against infection by soil-borne pathogens. Naturally disease-suppressive soils have been reported for diseases of a diverse range of agricultural crops worldwide yet the underlying mechanisms of disease suppression are still not completely understood. Two large greenhouse experiments, conducted during 2017/18 (Year 1) and 2018/19 (Year 2), determined that soils naturally suppressive to stem canker and black scurf of potato (caused by Rhizoctonia solani) are present in vegetable-arable cropping soils of the Auckland and Waikato regions of New Zealand. Soil was pre-treated with heat prior to inoculation with R. solani and compared with untreated and uninoculated controls to ascertain if stem canker and black scurf suppression was ‘general’, or ‘specific’ (i.e. transferable; possibly involving specific microorganisms). Rhizoctonia solani inoculation was also combined with transfer of one part test soil to nine parts of a known disease-conducive soil. Abiotic factors such as soil texture and organic matter content influenced black scurf incidence and severity. Soil microorganisms were also involved in disease suppression since black scurf incidence and severity markedly increased when they were eliminated or reduced by soil heat pre-treatment. Microbial profiling of the soils through sequencing revealed that taxa of geographically close soils of the same type had similar fungal and bacterial community structure and diversity even though they differed in their capacity to suppress black scurf. These results suggest that although the soil microbiome as a whole, was mainly responsible for soil disease suppressiveness, certain bacterial genera or species may play a role in black scurf suppression.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76619123","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 : 2022-07-14DOI: 10.30843/nzpp.2022.75.11758
M. Cripps, J. Mills, L. Villamizar, C. van Koten
The thistle biocontrol beetle, Cassida rubiginosa is established in New Zealand, but often not sufficiently abundant to achieve control of the weed, Cirsium arvense (Californian thistle). Mass production of the beetle could enhance biocontrol efforts through supplemental and inundative releases. We carried out an initial test of a semiartificial diet (containing host plant material) designed for laboratory mass production of the beetle. Larval survival rates were tested on diets with three different concentrations of preservatives (full, half, and no preservative), and compared to a positive control (leaf disc of Cirsium arvense), and a negative control (water). Only larvae on the leaf disc developed to the adult stage. Of the diets, the longest survival time was on the full preservative diet, with a mean mortality time of 8.8 ± 0.6 days, and a maximum survival time of 21 days. Although no larvae completed development on the diets, some important progress was achieved: (1) Neonate larvae were mobile on the diet; (2) larvae fed on the diet; and (3) there was adequate control of microbial contamination without being acutely toxic to the larvae. Further development of a diet for Cassida rubiginosa should focus on nutritional components for larval development.
{"title":"Initial test of a semiartificial diet for the thistle biocontrol beetle, Cassida rubiginosa","authors":"M. Cripps, J. Mills, L. Villamizar, C. van Koten","doi":"10.30843/nzpp.2022.75.11758","DOIUrl":"https://doi.org/10.30843/nzpp.2022.75.11758","url":null,"abstract":"The thistle biocontrol beetle, Cassida rubiginosa is established in New Zealand, but often not sufficiently abundant to achieve control of the weed, Cirsium arvense (Californian thistle). Mass production of the beetle could enhance biocontrol efforts through supplemental and inundative releases. We carried out an initial test of a semiartificial diet (containing host plant material) designed for laboratory mass production of the beetle. Larval survival rates were tested on diets with three different concentrations of preservatives (full, half, and no preservative), and compared to a positive control (leaf disc of Cirsium arvense), and a negative control (water). Only larvae on the leaf disc developed to the adult stage. Of the diets, the longest survival time was on the full preservative diet, with a mean mortality time of 8.8 ± 0.6 days, and a maximum survival time of 21 days. Although no larvae completed development on the diets, some important progress was achieved: (1) Neonate larvae were mobile on the diet; (2) larvae fed on the diet; and (3) there was adequate control of microbial contamination without being acutely toxic to the larvae. Further development of a diet for Cassida rubiginosa should focus on nutritional components for larval development.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82227256","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 : 2022-05-16DOI: 10.30843/nzpp.2022.75.11752
Anuar Morales-Rodriguez, C. Rowe, A. Chhagan, J. Poulton, Shirley S. Dobson, M. Astill, N. Mauchline, A. Puketapu, P. Rogers, J. Herrick, K. Stannard, Catherine McKenzie, C. McKenna
The larval parasitoid, Thripoctenus javae (Hymenoptera: Eulopidae), was introduced into New Zealand in 2001 as a biological control agent for greenhouse thrips, Heliothrips haemorrhoidalis. We have re-evaluated the establishment of T. javae at the release sites from Kerikeri to Gisborne and surveyed kiwifruit orchards in the Bay of Plenty to determine how widespread the parasitoid has become. Release sites were surveyed in autumn 2017 for greenhouse thrips. Foliage samples were collected from numerous host plants, where greenhouse thrips were found, and the number of T. javae pupae on each leaf were recorded. In 2018, a second survey for T. javae was conducted in Bay of Plenty; samples of cryptomeria (Cryptomeria japonica) shelterbelt foliage were collected from 65 kiwifruit orchards. Foliage samples were washed and pupae of T. javae were counted. Thripoctenus javae were recorded at 80% of the original release sites from Kerikeri to Gisborne. The parasitoid was found at all sites in Whangarei and Bay of Plenty, 50% of sites in Kerikeri, 33% of revisited sites in Gisborne as well as the single site in Auckland. No host populations of greenhouse thrips were found at four release sites (Kerikeri =2 and Gisborne =2). In Bay of Plenty, T. javae were found at 32 kiwifruit orchards (49% of the total surveyed). All of these orchards are new locality records for T. javae. The furthest distance T. javae was found from a release site was 55.4 km. The introduction of T. javae into New Zealand has been successful with the parasitoid recorded at 80% of the original release sites after 17 years. Dispersal is evident in the Bay of Plenty where we have detected T. javae at 32 new locations on kiwifruit orchards.
{"title":"Update on the establishment of Thripoctenus javae in New Zealand and new locality records in Bay of Plenty kiwifruit orchards","authors":"Anuar Morales-Rodriguez, C. Rowe, A. Chhagan, J. Poulton, Shirley S. Dobson, M. Astill, N. Mauchline, A. Puketapu, P. Rogers, J. Herrick, K. Stannard, Catherine McKenzie, C. McKenna","doi":"10.30843/nzpp.2022.75.11752","DOIUrl":"https://doi.org/10.30843/nzpp.2022.75.11752","url":null,"abstract":"The larval parasitoid, Thripoctenus javae (Hymenoptera: Eulopidae), was introduced into New Zealand in 2001 as a biological control agent for greenhouse thrips, Heliothrips haemorrhoidalis. We have re-evaluated the establishment of T. javae at the release sites from Kerikeri to Gisborne and surveyed kiwifruit orchards in the Bay of Plenty to determine how widespread the parasitoid has become.\u0000Release sites were surveyed in autumn 2017 for greenhouse thrips. Foliage samples were collected from numerous host plants, where greenhouse thrips were found, and the number of T. javae pupae on each leaf were recorded. In 2018, a second survey for T. javae was conducted in Bay of Plenty; samples of cryptomeria (Cryptomeria japonica) shelterbelt foliage were collected from 65 kiwifruit orchards. Foliage samples were washed and pupae of T. javae were counted.\u0000Thripoctenus javae were recorded at 80% of the original release sites from Kerikeri to Gisborne. The parasitoid was found at all sites in Whangarei and Bay of Plenty, 50% of sites in Kerikeri, 33% of revisited sites in Gisborne as well as the single site in Auckland. No host populations of greenhouse thrips were found at four release sites (Kerikeri =2 and Gisborne =2). In Bay of Plenty, T. javae were found at 32 kiwifruit orchards (49% of the total surveyed). All of these orchards are new locality records for T. javae. The furthest distance T. javae was found from a release site was 55.4 km.\u0000The introduction of T. javae into New Zealand has been successful with the parasitoid recorded at 80% of the original release sites after 17 years. Dispersal is evident in the Bay of Plenty where we have detected T. javae at 32 new locations on kiwifruit orchards.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"111 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86240472","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 : 2022-05-03DOI: 10.30843/nzpp.2022.75.11751
A. M. Thurston, L. Waller, L. Condron, A. Black
The oomycete Phytophthora agathidicida is the causal agent of kauri dieback, which threatens the survival of endemic kauri (Agathis australis) forests in Aotearoa|New Zealand. Current chemical control of P. agathidicida involves the application of either a mixture of halogenated tertiary amines or phosphite salts with some success, but neither treatment cures the disease. Recently, four anti-oomycete fungicides, all with different modes of action, have become commercially available. Here, we determined the inhibition potential of these fungicides on three P. agathidicida isolates, using agar dilution assays. The average concentration required to inhibit mycelial growth by 50% (EC50) for ethaboxam, fluopicolide, and mandipropamid was 0.0916, 0.372, and 0.0196 µg/mL, respectively. Inhibition of P. agathidicida mycelia by oxathiapiprolin and its commercial formulation, Zorvec® Enicade®, was 0.000152 and 0.000309 µg/mL, respectively. Based on the EC50 values reported in this study, these fungicides are the most effective inhibitors of P. agathidicida mycelia when compared to previously screened fungicides, natural products, and plant extracts. Thus, their performance in this initial screening supports further research into their potential use as a kauri dieback management tool.
{"title":"Sensitivity of the soil-borne pathogen Phytophthora agathidicida, the causal agent of kauri dieback, to the anti-oomycete fungicides ethaboxam, fluopicolide, mandipropamid, and oxathiapiprolin","authors":"A. M. Thurston, L. Waller, L. Condron, A. Black","doi":"10.30843/nzpp.2022.75.11751","DOIUrl":"https://doi.org/10.30843/nzpp.2022.75.11751","url":null,"abstract":"The oomycete Phytophthora agathidicida is the causal agent of kauri dieback, which threatens the survival of endemic kauri (Agathis australis) forests in Aotearoa|New Zealand. Current chemical control of P. agathidicida involves the application of either a mixture of halogenated tertiary amines or phosphite salts with some success, but neither treatment cures the disease. Recently, four anti-oomycete fungicides, all with different modes of action, have become commercially available. Here, we determined the inhibition potential of these fungicides on three P. agathidicida isolates, using agar dilution assays. The average concentration required to inhibit mycelial growth by 50% (EC50) for ethaboxam, fluopicolide, and mandipropamid was 0.0916, 0.372, and 0.0196 µg/mL, respectively. Inhibition of P. agathidicida mycelia by oxathiapiprolin and its commercial formulation, Zorvec® Enicade®, was 0.000152 and 0.000309 µg/mL, respectively. Based on the EC50 values reported in this study, these fungicides are the most effective inhibitors of P. agathidicida mycelia when compared to previously screened fungicides, natural products, and plant extracts. Thus, their performance in this initial screening supports further research into their potential use as a kauri dieback management tool.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"111 3S 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73197966","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 : 2022-04-19DOI: 10.30843/nzpp.2022.75.11749
F. H. MacDonald, P. Wright, Bryan N. Hart, Lindy F. Guo, S. K. Hunt, G. Walker
Tomato potato psyllid (TPP), Bactericera cockerelli (Sulc) (Hemiptera: Triozidae), is the vector for “Candidatus Liberibacter solanacearum” (CLso), which causes the serious disease “zebra chip” (ZC) of potatoes. Between 2016 and 2019, a reduced-insecticide approach to control TPP was evaluated. We compared a standard-insecticide weekly spray regime that included Integrated Pest Management (IPM)-compatible insecticides plus JMS Stylet Oil® (JMS) as a wetting agent, with a reduced-insecticide regime where we used the oil on its own on alternate weeks with the insecticide/oil mixtures. Spray programme start dates were determined by: (1) crop scouting; (2) sticky-trap monitoring; and (3) degree-day calculation. Crop scouting combined with a sticky-trap action threshold and degree-day data was an effective method for determining when to start spraying. The most substantial reduction in insecticides was achieved by alternating weekly insecticides with the oil formulation on its own. Sub-samples of TPP from sticky traps situated in the trials tested for CLso confirmed the presence of the bacteria in (commonly known as ‘hot’) TPP throughout the trials. The reduced-treatment approach gave statistically similar levels of ZC to the standard insecticide spray programme.
{"title":"On-farm trials towards reduced insecticides in main crop potatoes in the Waikato Region of New Zealand","authors":"F. H. MacDonald, P. Wright, Bryan N. Hart, Lindy F. Guo, S. K. Hunt, G. Walker","doi":"10.30843/nzpp.2022.75.11749","DOIUrl":"https://doi.org/10.30843/nzpp.2022.75.11749","url":null,"abstract":"Tomato potato psyllid (TPP), Bactericera cockerelli (Sulc) (Hemiptera: Triozidae), is the vector for “Candidatus Liberibacter solanacearum” (CLso), which causes the serious disease “zebra chip” (ZC) of potatoes. Between 2016 and 2019, a reduced-insecticide approach to control TPP was evaluated. We compared a standard-insecticide weekly spray regime that included Integrated Pest Management (IPM)-compatible insecticides plus JMS Stylet Oil® (JMS) as a wetting agent, with a reduced-insecticide regime where we used the oil on its own on alternate weeks with the insecticide/oil mixtures. Spray programme start dates were determined by: (1) crop scouting; (2) sticky-trap monitoring; and (3) degree-day calculation. Crop scouting combined with a sticky-trap action threshold and degree-day data was an effective method for determining when to start spraying. The most substantial reduction in insecticides was achieved by alternating weekly insecticides with the oil formulation on its own. Sub-samples of TPP from sticky traps situated in the trials tested for CLso confirmed the presence of the bacteria in (commonly known as ‘hot’) TPP throughout the trials. The reduced-treatment approach gave statistically similar levels of ZC to the standard insecticide spray programme.\u0000 ","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90235965","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 : 2021-12-17DOI: 10.30843/nzpp.2021.74.11747
K. Everett, I. Pushparajah, R. Scheper
Neonectria ditissima causes a debilitating apple tree canker disease. We determined the efficacy of polymerase chain reaction primers, originally designed for European strains, by sequencing New Zealand strains. The concatenated ribosomal inter-transcribed spacer and β-tubulin gene regions of 17 New Zealand isolates were compared with those of two European strains by phylogenetic analysis. New Zealand and European isolates of N. ditissima were in the same clade, suggesting that there has been little change in these gene regions following introduction to New Zealand. There was 100% homology with Bt-FW135 and Bt-RW284 primers. Based on sequencing 17 New Zealand isolates from several locations, these polymerase chain reaction primers can be relied upon to amplify New Zealand isolates of N. ditissima.
{"title":"Phylogenetic analysis shows that New Zealand isolates of Neonectria ditissima are similar to European isolates","authors":"K. Everett, I. Pushparajah, R. Scheper","doi":"10.30843/nzpp.2021.74.11747","DOIUrl":"https://doi.org/10.30843/nzpp.2021.74.11747","url":null,"abstract":"Neonectria ditissima causes a debilitating apple tree canker disease. We determined the efficacy of polymerase chain reaction primers, originally designed for European strains, by sequencing New Zealand strains. The concatenated ribosomal inter-transcribed spacer and β-tubulin gene regions of 17 New Zealand isolates were compared with those of two European strains by phylogenetic analysis. New Zealand and European isolates of N. ditissima were in the same clade, suggesting that there has been little change in these gene regions following introduction to New Zealand. There was 100% homology with Bt-FW135 and Bt-RW284 primers. Based on sequencing 17 New Zealand isolates from several locations, these polymerase chain reaction primers can be relied upon to amplify New Zealand isolates of N. ditissima.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78618257","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 : 2021-12-16DOI: 10.30843/nzpp.2021.74.11748
L. Vorster, R. Butler, L. Turner, E. Patrick, R. Campbell, S. Orchard, M. Walter
The effects of nitrogen on the interaction between apple trees and European canker caused by Neonectria ditissima are not well understood. Previous field and laboratory studies have shown that nitrogen affects N. ditissima disease development, germination and germ-tube growth in vitro but the type of nitrogen source has not been examined in vivo. Therefore, the aim of this study was to determine the effects of root-applied nitrogen from different sources on the development of European canker on inoculated potted trees. One-year-old ‘Royal Gala’ trees were planted in a low-nitrogen growth substrate and treated with a range of concentrations of calcium ammonium nitrate (CAN) or other nitrogen sources (Ca(NO3)2, KNO3, (NH4)2SO4, NH4NO3, urea, YaraMila™) at equivalent molar rates of nitrogen as the highest CAN treatment. Treatments were applied during the growing season (Nov to May). The control treatment received no applied nitrogen. Bud and leaf scar wounds were inoculated at leaf fall with N. ditissima conidia. Tree growth and health, disease progression and leaf nitrogen content were monitored. The rate of nitrogen application affected tree diameter and leaf nitrogen content while the nitrogen source mainly affected tree survival, powdery mildew incidence, leaf weights, leaf nitrogen and European canker symptom expression. Trees treated with (NH4)2SO4 had the lowest survival rates and highest leaf nitrogen content. Disease expression was highest with NH4NO3 and lowest with KNO3 applications. The control plants (which received no additional nitrogen), showed the least amount of both growth and disease expression. Applications of CAN, even at the lowest rate (20 g), increased disease susceptibility. Increasing rates of CAN applications did not significantly increase disease incidence. Nitrogen concentration is an important factor in the disease development of European canker of apple. Field evaluation is recommended to further validate these results.
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Pub Date : 2021-11-23DOI: 10.30843/nzpp.2021.74.11738
Zachary Ngow, T. James, C. Buddenhagen
Despite an extensive history of research into herbicide resistance in New Zealand maize, some aspects remain understudied. Herbicide resistance was first detected in New Zealand in the 1980s in maize crops, with atrazine resistance in Chenopodium album L. and Persicaria maculosa Gray. Since then, Chenopodium album has also developed resistance to dicamba, and in the last five years Digitaria sanguinalis (L.) Scop. populations have been reported to be resistant to nicosulfuron. Here we estimate the risk of herbicide resistance arising in 39 common maize weeds. A list of weeds associated with maize was generated, omitting uncommon weeds and those that grow outside of the maize growing season. Weeds were ranked for their risk of evolving herbicide resistance with a scoring protocol that accounts for the specific herbicides used in New Zealand maize. Seven weed species were classified as having a high risk of developing herbicide resistance: Echinochloa crus-galli (L.) P.Beauv., Chenopodium album, Eleusine indica (L.) Gaertn., Xanthium strumarium L., Amaranthus powellii S.Watson, Solanum nigrum L. and Digitaria sanguinalis. Seventeen species were classed as moderate risk, and 15 were low risk. Herbicide classes associated with more resistant species were classed as high risk,these included acetohydroxy acid synthase inhibitors and photosystem-II inhibitors. Synthetic auxins had a moderate risk but only two herbicides in this class (dicamba and clopyralid) are registered for maize in New Zealand. Other herbicide mode-of-action groups used in maize were low risk. We recommend outreach to farmers regarding weed-control strategies that prevent high-risk species from developing resistance. High-risk herbicide groups should be monitored for losses of efficacy. Resistance surveys should focus on these species and herbicides.
尽管对新西兰玉米的抗除草剂性进行了广泛的研究，但有些方面仍未得到充分研究。20世纪80年代，新西兰首次在玉米作物中检测到除草剂抗性，其中Chenopodium album L.和Persicaria maculosa Gray对莠去津具有抗性。此后，Chenopodium album也对麦草畏产生了抗性，近5年来，Digitaria sanguinalis (L.)也对麦草畏产生了抗性。吟游诗人。据报道，种群对尼科磺隆具有抗性。在这里，我们估计了39种常见玉米杂草产生的抗除草剂风险。生成了一份与玉米相关的杂草清单，剔除了不常见的杂草和那些在玉米生长季节之外生长的杂草。根据新西兰玉米使用的特定除草剂的评分方案，对杂草进化出的抗除草剂风险进行了排名。7种杂草被列为具有除草剂抗性的高风险杂草:P.Beauv。Chenopodium album, Eleusine indica (L.)Gaertn。、苍耳、苦苋菜、龙葵、马地黄。17种为中度风险，15种为低风险。与抗性较强的物种相关的除草剂类别被列为高风险，其中包括乙酰羟基酸合成酶抑制剂和光系统ii抑制剂。合成生长素具有中等风险，但这类除草剂中只有两种(麦草畏和氯吡虫啉)在新西兰登记用于玉米。玉米中使用的其他除草剂作用方式组风险较低。我们建议向农民宣传预防高风险物种产生抗性的杂草控制策略。应监测高危除草剂群的药效损失。抗性调查应集中在这些物种和除草剂上。
{"title":"A herbicide resistance risk assessment for weeds in maize in New Zealand","authors":"Zachary Ngow, T. James, C. Buddenhagen","doi":"10.30843/nzpp.2021.74.11738","DOIUrl":"https://doi.org/10.30843/nzpp.2021.74.11738","url":null,"abstract":"Despite an extensive history of research into herbicide resistance in New Zealand maize, some aspects remain understudied. Herbicide resistance was first detected in New Zealand in the 1980s in maize crops, with atrazine resistance in Chenopodium album L. and Persicaria maculosa Gray. Since then, Chenopodium album has also developed resistance to dicamba, and in the last five years Digitaria sanguinalis (L.) Scop. populations have been reported to be resistant to nicosulfuron. Here we estimate the risk of herbicide resistance arising in 39 common maize weeds. A list of weeds associated with maize was generated, omitting uncommon weeds and those that grow outside of the maize growing season. Weeds were ranked for their risk of evolving herbicide resistance with a scoring protocol that accounts for the specific herbicides used in New Zealand maize. Seven weed species were classified as having a high risk of developing herbicide resistance: Echinochloa crus-galli (L.) P.Beauv., Chenopodium album, Eleusine indica (L.) Gaertn., Xanthium strumarium L., Amaranthus powellii S.Watson, Solanum nigrum L. and Digitaria sanguinalis. Seventeen species were classed as moderate risk, and 15 were low risk. Herbicide classes associated with more resistant species were classed as high risk,these included acetohydroxy acid synthase inhibitors and photosystem-II inhibitors. Synthetic auxins had a moderate risk but only two herbicides in this class (dicamba and clopyralid) are registered for maize in New Zealand. Other herbicide mode-of-action groups used in maize were low risk. We recommend outreach to farmers regarding weed-control strategies that prevent high-risk species from developing resistance. High-risk herbicide groups should be monitored for losses of efficacy. Resistance surveys should focus on these species and herbicides.","PeriodicalId":19180,"journal":{"name":"New Zealand Plant Protection","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88583990","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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