Maureen Ocallaghan - Academia.edu (original) (raw)

Papers by Maureen Ocallaghan

Science China. Life Sciences/Science China. Life sciences, Feb 2, 2024

New Zealand Plant Protection

The bacterium Serratia entomophila has been incorporated into prill formulations to improve distr... more The bacterium Serratia entomophila has been incorporated into prill formulations to improve distribution and application of this insect pathogen to pasture for biological control of the New Zealand grass grub Costelytra zealandica While bacteria can survive in ambient conditions for long periods within the prills their field efficacy depends on successful release of bacteria from the prills and colonisation of the surrounding soil Laboratory experiments were conducted to determine the effects of soil moisture on rate of release of bacteria from prill formulations Prills were held in soil adjusted to four soil moisture contents (ranging from field capacity to wilting point) and the release of bacteria was determined by dilution plating Bacteria were released most rapidly at high soil moistures and populations were maintained at 103104 colony forming units per g soil in most treatments Measurement of release of S entomophila from prills in soil cores subjected to various watering regi...

New Zealand Plant Protection

Pseudomonas fluorescens strain F113 which has biocontrol capacity against the plant pathogenic fu... more Pseudomonas fluorescens strain F113 which has biocontrol capacity against the plant pathogenic fungus Pythium ultimum was formulated and applied to onion seed using patented biopolymer technology developed at AgResearch Lincoln Initial loadings on seeds ranged between 86 x 10611 x 107 bacteria/seed In a preliminary screening of four different formulations shelf life studies indicated that most formulations maintained high cell numbers on seed stored at 4deg;C for up to 70 days Bacterial numbers declined on seed stored at 20deg;C but significant numbers of bacteria remained viable after 70 days storage In a second experiment the two formulations giving best shelflife at 20deg;C were monitored for stability at 20deg;C for 4 weeks Packaging material had a significant effect on bacterial survival on seed Germination of freshly treated seeds was not affected by seed treatment The study has demonstrated the potential to treat seed with fluorescent pseudomonads with biocontrol capability

Plant and Soil, 2005

Antimicrobial peptide magainin II, isolated from the skin of the African clawed toad, has shown a... more Antimicrobial peptide magainin II, isolated from the skin of the African clawed toad, has shown activity in vitro against a range of microorganisms. Transgenic potato lines expressing a synthetic magainin gene show improved resistance to the bacterial plant pathogen, Erwinia carotovora. Culturable bacterial and fungal communities associated with magainin-producing potato plants were compared with those communities from the non-transgenic parental control and with another potato cultivar. Total numbers of aerobic bacteria recovered from the leaves of the magainin-producing line, its non-transgenic parent line and an unrelated cultivar did not differ significantly. There were no detectable differences in the numbers of Gram-positive and Gram-negative bacteria, pseudomonad populations or fungi recovered from foliage from the three plant lines. Bacterial populations recovered from the roots of a magainin-expressing plant line did not differ significantly from populations recovered from the unmodified parental line. Tubers from the magainin-expressing transgenic potatoes, however, had significantly lower total numbers of bacteria than tubers produced by unmodified plants. In vitro testing of rhizosphere isolates against magainin analogues found that bacterial isolates varied in their susceptibility to the peptides. There were no significant differences in the total numbers of fungi and yeasts recovered from the various plant lines, with one exception: higher numbers of fungi were recovered from roots of magainin-expressing plants than the unmodified control plants.

New Zealand Journal of Zoology, 1993

A checklist of records of naturally occurring insect-pathogenic microbes and nematodes in New Zea... more A checklist of records of naturally occurring insect-pathogenic microbes and nematodes in New Zealand is presented. All records are listed by pathogen group (fungi, bacteria, protozoa, viruses, rickettsia, and nematodes) and also by host insect order and species. Each record is referenced to the original author, and important subsequent references have been included, where appropriate. The checklist should be updated periodically to assist researchers.

Global Change Biology, 2009

Atmospheric concentrations of the greenhouse gas nitrous oxide (N 2 O) have continued to rise sin... more Atmospheric concentrations of the greenhouse gas nitrous oxide (N 2 O) have continued to rise since the advent of the industrial era, largely because of the increase in agricultural land use. The urine deposited by grazing ruminant animals is a major global source of agricultural N 2 O. With the first commitment period for reducing greenhouse gas emissions under the Kyoto Protocol now underway, mitigation options for ruminant urine N 2 O emissions are urgently needed. Recent studies showed that increasing the urinary concentration of the minor urine constituent hippuric acid resulted in reduced emissions of N 2 O from a sandy soil treated with synthetic bovine urine, due to a reduction in denitrification. A similar effect was seen when benzoic acid, a product of hippuric acid hydrolysis, was used. This current laboratory experiment aimed to investigate these effects using real cow urine for the first time. Increased concentrations of hippuric acid or benzoic acid in the urine led to reduction of N 2 O emissions by 65% (from 17% to o6% N applied), with no difference between the two acid treatments. Ammonia volatilization did not increase significantly with increased hippuric acid or benzoic acid concentrations in the urine applied. Therefore, there was a net reduction in gaseous N loss from the soil with higher urinary concentrations of both hippuric acid and benzoic acid. The results show that elevating hippuric acid in the urine had a marked negative effect on both nitrification and denitrification rates and on subsequent N 2 O fluxes. This study indicates the potential for developing a novel mitigation strategy based on manipulation of urine composition through ruminant diet.

Applied Soil Ecology, 2012

ABSTRACT Export Date: 18 May 2013, Source: Scopus

Applied and Environmental Microbiology, 2006

Some strains of Serratia entomophila and S. proteamaculans cause amber disease of the grass grub ... more Some strains of Serratia entomophila and S. proteamaculans cause amber disease of the grass grub Costelytra zealandica (Coleoptera: Scarabaeidae). Three genes required for virulence, sepABC , are located on a large plasmid, pADAP. Sequence analysis suggests that the sepABC gene cluster may be part of a horizontally mobile region. This study presents evidence for the putative mobility of the sep genes of pADAP. Southern blot analysis showed that orthologues of the sep genes reside on plasmids within S. entomophila , S. liquefaciens , S. proteamaculans , and a plasmid from Yersinia frederiksenii . Three plasmids hybridized to the pADAP sep virulence-associated region but not the pADAP replication and conjugation regions. Subsequent DNA sequence analysis of the Y. frederiksenii sep -like genes, designated tcYF1 and tcYF2 , showed that they had 88% and 87% DNA identity to sepA and sepB , respectively. These results indicate that the sep genes are part of a discrete horizontally mobile r...

Annual Review of Entomology, 2005

▪ Insect resistance, based on Bacillus thuringiensis (Bt) endotoxins, is the second most widely... more ▪ Insect resistance, based on Bacillus thuringiensis (Bt) endotoxins, is the second most widely used trait (after herbicide resistance) in commercial genetically modified (GM) crops. Other modifications for insect resistance, such as proteinase inhibitors and lectins, are also being used in many experimental crops. The extensive testing on nontarget plant-feeding insects and beneficial species that has accompanied the long-term and wide-scale use of Bt plants has not detected significant adverse effects. GM plants expressing other insect-resistant proteins that have a broader spectrum of activity have been tested on only a limited number of nontarget species. Little is known about the persistence of transgene-derived proteins in soil, with the exception of Bt endotoxins, which can persist in soil for several months. Bt plants appear to have little impact on soil biota such as earthworms, collembolans, and general soil microflora. Further research is required on the effects of GM p...

New Zealand Plant Protection

Microbial control of soil dwelling pests and pathogens depends on the survival of microbial inocu... more Microbial control of soil dwelling pests and pathogens depends on the survival of microbial inocula in soil Three microbes Beauveria bassiana A6 Serratia entomophila 626 and Pseudomonas fluorescens CHA0Rif were inoculated into soil microcosms at three soil moistures and temperatures Survival was determined at regular intervals Beauveria bassiana survived well in soil; after 3 months the populations were maintained at levels close to those immediately following inoculation under most soil conditions Serratia entomophila and P fluorescens populations declined gradually Soil moisture impacted on survival of P fluorescens with populations declining most rapidly in the dry soil at all temperatures Pseudomonas fluorescens was not recovered after 54 days at 20C The rate of population decline of S entomophila increased with soil temperature but populations remained above the minimum level of detection after three months with soil moisture having little effect on survival Formulation of S en...

Intensively grazed dairy pastures in New Zealand routinely receive concentrated inputs of nitroge... more Intensively grazed dairy pastures in New Zealand routinely receive concentrated inputs of nitrogen (N) both through application of fertiliser and deposition of urine by grazing animals. Leaching of nitrate from soil into aquifers, rivers and lakes is a source of increasing environmental and public health concern. Nitrification inhibitors have been shown to decrease leaching and denitrification from urea- and ammonium-based fertilisers and from urine patches in pastures. To date there have been few studies on effects of nitrification inhibitors on non-target soil biota. Three laboratory experiments were carried out to measure the short term effects of a nitrification inhibitor, dicyandiamide (DCD), on diversity of soil bacterial populations, earthworms and Collembola. Molecular analysis of the soil bacterial community indicated that application of DCD to soil did not affect the composition of the predominant bacterial phyla present in soil, unlike the addition of bovine urine which c...

A lysimeter experiment was conducted to investigate the effect of past and current management pra... more A lysimeter experiment was conducted to investigate the effect of past and current management practices on soil microbial biomass, activity and community composition. Intact monolith lysimeters were taken from sites of the same soil type that had been under long-term organic and conventional crop management. They were subjected to the same crop rotation and managed according to best organic and conventional practices. Mineral N loss was determined in leachates and soil samples taken before the experiment and after 30 months were analysed for biological soil properties, including microbial diversity. Results indicated that leaching losses were similar for all treatments and that crop was the main influence on microbial biomass composition and size, while microbial activity was determined by management history.

Environmental …, 2010

Determining the effects of genetically modified (GM) crops on non-target organisms is essential a... more Determining the effects of genetically modified (GM) crops on non-target organisms is essential as many nontarget species provide important ecological functions. However, it is simply not possible to collect field data on more than a few potential non-target species present in the receiving environment of a GM crop. While risk assessment must be rigorous, new approaches are necessary to improve the efficiency of the process. Utilisation of published information and existing data on the phenology and population dynamics of test species in the field can be combined with limited amounts of experimental biosafety data to predict possible outcomes on species persistence. This paper presents an example of an approach where data from laboratory experiments and field studies on phenology are combined using predictive modelling. Using the New Zealand native weevil species Nicaeana cervina as a case study, we could predict that oviposition rates of the weevil feeding on a GM ryegrass could be reduced by up to 30% without threat to populations of the weevil in pastoral ecosystems. In addition, an experimentally established correlation between feeding level and oviposition led to the prediction that a consistent reduction in feeding of 50% or higher indicated a significant risk to the species and could potentially lead to local extinctions. This approach to biosafety risk assessment, maximising the use of pre-existing field and laboratory data on non-target species, can make an important contribution to informed decision-making by regulatory authorities and developers of new technologies.

Environmental …, 2007

Effects of tobacco genetically modified to express the protease inhibitor bovine spleen trypsin i... more Effects of tobacco genetically modified to express the protease inhibitor bovine spleen trypsin inhibitor (BSTI) were examined in laboratory assays against three earthworm and one collembolan species. BSTI is a serine protease inhibitor that can bind to the digestive ...

New Zealand Plant Protection

Little is known about the impacts of transgenic plants and microorganisms on soil biota and proce... more Little is known about the impacts of transgenic plants and microorganisms on soil biota and processes despite the large number of field releases of transgenic crops Recent work has shown that transgenic plants can cause changes in the soil biota (both invertebrates and microorganisms) associated with these plants Often the changes are transient but their impact on the soil ecosystem remains unknown Horizontal gene transfer from genetically modified (GM) bacteria to indigenous soil bacteria has been demonstrated but movement of genes from transgenic plants if it occurs at all has not yet been detected in natural systems Soil invertebrates appear to play an important role in horizontal gene transfer between bacteria in soil

New Zealand Plant Protection

A granular formulation of Serratia entomophila has been developed to improve shelflife and storag... more A granular formulation of Serratia entomophila has been developed to improve shelflife and storage characteristics of this bacterium which is used as a microbial control agent of the New Zealand grass grub Bacterial establishment and survival of bacteria released from the granular and liquid formulations were assessed in a laboratory experiment Bacteria were enumerated by dilution plating onto Serratia selective agar Serratia entomophila populations in soil inoculated with granules remained stable in soil for up to five months at a range of soil moisture levels Bacterial numbers declined more rapidly when soil was inoculated with the liquid formulation High numbers of bacteria remained viable in the granules throughout the experiment demonstrating the potential for sustained release of inoculum after application of the biopesticide granules

New Zealand Plant Protection

New Zealand Plant Protection

Biopesticides can provide effective control of existing and invasive invertebrate pests and disea... more Biopesticides can provide effective control of existing and invasive invertebrate pests and diseases impacting on New Zealands primary sector production and combat new pests emerging as a result of landuse change farming intensification and climate change While the international biopesticide market is undergoing rapid growth at present assisted by regulatory environments favourable to biopesticide registration and uptake biopesticides are not widely used in New Zealand The number of biopesticides registered under the Agriculture Compounds and Veterinary Medicines Act (Ministry for Primary Industries MPI) has slowly increased from 11 products in 1991 to 33 in 2010 with 49 registered in 2015 However only a limited number of these products are actively marketed and used by growers at present To play an increasing role in New Zealands sustainable production systems next generation biopesticides will need to have levels of efficacy comparable to currently available controls and will be a...

Recent studies implicate biochar as a potential nitrous oxide mitigation agent as weU as a carbon... more Recent studies implicate biochar as a potential nitrous oxide mitigation agent as weU as a carbon sink. The objectives ofth;s study were to: (1) Investigate the ability of biochar to reduce emissions of nitrous oxide (N 2 0) from bovine urine-treated cores packed with a Wakanui silt loam (2) Determine the extent to which shifts in total and active bacterial and archaeal ammonia oxidizer communities in these soil cores explain observed N-turnover.

Science China. Life Sciences/Science China. Life sciences, Feb 2, 2024

New Zealand Plant Protection

The bacterium Serratia entomophila has been incorporated into prill formulations to improve distr... more The bacterium Serratia entomophila has been incorporated into prill formulations to improve distribution and application of this insect pathogen to pasture for biological control of the New Zealand grass grub Costelytra zealandica While bacteria can survive in ambient conditions for long periods within the prills their field efficacy depends on successful release of bacteria from the prills and colonisation of the surrounding soil Laboratory experiments were conducted to determine the effects of soil moisture on rate of release of bacteria from prill formulations Prills were held in soil adjusted to four soil moisture contents (ranging from field capacity to wilting point) and the release of bacteria was determined by dilution plating Bacteria were released most rapidly at high soil moistures and populations were maintained at 103104 colony forming units per g soil in most treatments Measurement of release of S entomophila from prills in soil cores subjected to various watering regi...

New Zealand Plant Protection

Pseudomonas fluorescens strain F113 which has biocontrol capacity against the plant pathogenic fu... more Pseudomonas fluorescens strain F113 which has biocontrol capacity against the plant pathogenic fungus Pythium ultimum was formulated and applied to onion seed using patented biopolymer technology developed at AgResearch Lincoln Initial loadings on seeds ranged between 86 x 10611 x 107 bacteria/seed In a preliminary screening of four different formulations shelf life studies indicated that most formulations maintained high cell numbers on seed stored at 4deg;C for up to 70 days Bacterial numbers declined on seed stored at 20deg;C but significant numbers of bacteria remained viable after 70 days storage In a second experiment the two formulations giving best shelflife at 20deg;C were monitored for stability at 20deg;C for 4 weeks Packaging material had a significant effect on bacterial survival on seed Germination of freshly treated seeds was not affected by seed treatment The study has demonstrated the potential to treat seed with fluorescent pseudomonads with biocontrol capability

Plant and Soil, 2005

Antimicrobial peptide magainin II, isolated from the skin of the African clawed toad, has shown a... more Antimicrobial peptide magainin II, isolated from the skin of the African clawed toad, has shown activity in vitro against a range of microorganisms. Transgenic potato lines expressing a synthetic magainin gene show improved resistance to the bacterial plant pathogen, Erwinia carotovora. Culturable bacterial and fungal communities associated with magainin-producing potato plants were compared with those communities from the non-transgenic parental control and with another potato cultivar. Total numbers of aerobic bacteria recovered from the leaves of the magainin-producing line, its non-transgenic parent line and an unrelated cultivar did not differ significantly. There were no detectable differences in the numbers of Gram-positive and Gram-negative bacteria, pseudomonad populations or fungi recovered from foliage from the three plant lines. Bacterial populations recovered from the roots of a magainin-expressing plant line did not differ significantly from populations recovered from the unmodified parental line. Tubers from the magainin-expressing transgenic potatoes, however, had significantly lower total numbers of bacteria than tubers produced by unmodified plants. In vitro testing of rhizosphere isolates against magainin analogues found that bacterial isolates varied in their susceptibility to the peptides. There were no significant differences in the total numbers of fungi and yeasts recovered from the various plant lines, with one exception: higher numbers of fungi were recovered from roots of magainin-expressing plants than the unmodified control plants.

New Zealand Journal of Zoology, 1993

A checklist of records of naturally occurring insect-pathogenic microbes and nematodes in New Zea... more A checklist of records of naturally occurring insect-pathogenic microbes and nematodes in New Zealand is presented. All records are listed by pathogen group (fungi, bacteria, protozoa, viruses, rickettsia, and nematodes) and also by host insect order and species. Each record is referenced to the original author, and important subsequent references have been included, where appropriate. The checklist should be updated periodically to assist researchers.

Global Change Biology, 2009

Atmospheric concentrations of the greenhouse gas nitrous oxide (N 2 O) have continued to rise sin... more Atmospheric concentrations of the greenhouse gas nitrous oxide (N 2 O) have continued to rise since the advent of the industrial era, largely because of the increase in agricultural land use. The urine deposited by grazing ruminant animals is a major global source of agricultural N 2 O. With the first commitment period for reducing greenhouse gas emissions under the Kyoto Protocol now underway, mitigation options for ruminant urine N 2 O emissions are urgently needed. Recent studies showed that increasing the urinary concentration of the minor urine constituent hippuric acid resulted in reduced emissions of N 2 O from a sandy soil treated with synthetic bovine urine, due to a reduction in denitrification. A similar effect was seen when benzoic acid, a product of hippuric acid hydrolysis, was used. This current laboratory experiment aimed to investigate these effects using real cow urine for the first time. Increased concentrations of hippuric acid or benzoic acid in the urine led to reduction of N 2 O emissions by 65% (from 17% to o6% N applied), with no difference between the two acid treatments. Ammonia volatilization did not increase significantly with increased hippuric acid or benzoic acid concentrations in the urine applied. Therefore, there was a net reduction in gaseous N loss from the soil with higher urinary concentrations of both hippuric acid and benzoic acid. The results show that elevating hippuric acid in the urine had a marked negative effect on both nitrification and denitrification rates and on subsequent N 2 O fluxes. This study indicates the potential for developing a novel mitigation strategy based on manipulation of urine composition through ruminant diet.

Applied Soil Ecology, 2012

ABSTRACT Export Date: 18 May 2013, Source: Scopus

Applied and Environmental Microbiology, 2006

Some strains of Serratia entomophila and S. proteamaculans cause amber disease of the grass grub ... more Some strains of Serratia entomophila and S. proteamaculans cause amber disease of the grass grub Costelytra zealandica (Coleoptera: Scarabaeidae). Three genes required for virulence, sepABC , are located on a large plasmid, pADAP. Sequence analysis suggests that the sepABC gene cluster may be part of a horizontally mobile region. This study presents evidence for the putative mobility of the sep genes of pADAP. Southern blot analysis showed that orthologues of the sep genes reside on plasmids within S. entomophila , S. liquefaciens , S. proteamaculans , and a plasmid from Yersinia frederiksenii . Three plasmids hybridized to the pADAP sep virulence-associated region but not the pADAP replication and conjugation regions. Subsequent DNA sequence analysis of the Y. frederiksenii sep -like genes, designated tcYF1 and tcYF2 , showed that they had 88% and 87% DNA identity to sepA and sepB , respectively. These results indicate that the sep genes are part of a discrete horizontally mobile r...

Annual Review of Entomology, 2005

▪ Insect resistance, based on Bacillus thuringiensis (Bt) endotoxins, is the second most widely... more ▪ Insect resistance, based on Bacillus thuringiensis (Bt) endotoxins, is the second most widely used trait (after herbicide resistance) in commercial genetically modified (GM) crops. Other modifications for insect resistance, such as proteinase inhibitors and lectins, are also being used in many experimental crops. The extensive testing on nontarget plant-feeding insects and beneficial species that has accompanied the long-term and wide-scale use of Bt plants has not detected significant adverse effects. GM plants expressing other insect-resistant proteins that have a broader spectrum of activity have been tested on only a limited number of nontarget species. Little is known about the persistence of transgene-derived proteins in soil, with the exception of Bt endotoxins, which can persist in soil for several months. Bt plants appear to have little impact on soil biota such as earthworms, collembolans, and general soil microflora. Further research is required on the effects of GM p...

New Zealand Plant Protection

Microbial control of soil dwelling pests and pathogens depends on the survival of microbial inocu... more Microbial control of soil dwelling pests and pathogens depends on the survival of microbial inocula in soil Three microbes Beauveria bassiana A6 Serratia entomophila 626 and Pseudomonas fluorescens CHA0Rif were inoculated into soil microcosms at three soil moistures and temperatures Survival was determined at regular intervals Beauveria bassiana survived well in soil; after 3 months the populations were maintained at levels close to those immediately following inoculation under most soil conditions Serratia entomophila and P fluorescens populations declined gradually Soil moisture impacted on survival of P fluorescens with populations declining most rapidly in the dry soil at all temperatures Pseudomonas fluorescens was not recovered after 54 days at 20C The rate of population decline of S entomophila increased with soil temperature but populations remained above the minimum level of detection after three months with soil moisture having little effect on survival Formulation of S en...

Intensively grazed dairy pastures in New Zealand routinely receive concentrated inputs of nitroge... more Intensively grazed dairy pastures in New Zealand routinely receive concentrated inputs of nitrogen (N) both through application of fertiliser and deposition of urine by grazing animals. Leaching of nitrate from soil into aquifers, rivers and lakes is a source of increasing environmental and public health concern. Nitrification inhibitors have been shown to decrease leaching and denitrification from urea- and ammonium-based fertilisers and from urine patches in pastures. To date there have been few studies on effects of nitrification inhibitors on non-target soil biota. Three laboratory experiments were carried out to measure the short term effects of a nitrification inhibitor, dicyandiamide (DCD), on diversity of soil bacterial populations, earthworms and Collembola. Molecular analysis of the soil bacterial community indicated that application of DCD to soil did not affect the composition of the predominant bacterial phyla present in soil, unlike the addition of bovine urine which c...

A lysimeter experiment was conducted to investigate the effect of past and current management pra... more A lysimeter experiment was conducted to investigate the effect of past and current management practices on soil microbial biomass, activity and community composition. Intact monolith lysimeters were taken from sites of the same soil type that had been under long-term organic and conventional crop management. They were subjected to the same crop rotation and managed according to best organic and conventional practices. Mineral N loss was determined in leachates and soil samples taken before the experiment and after 30 months were analysed for biological soil properties, including microbial diversity. Results indicated that leaching losses were similar for all treatments and that crop was the main influence on microbial biomass composition and size, while microbial activity was determined by management history.

Environmental …, 2010

Determining the effects of genetically modified (GM) crops on non-target organisms is essential a... more Determining the effects of genetically modified (GM) crops on non-target organisms is essential as many nontarget species provide important ecological functions. However, it is simply not possible to collect field data on more than a few potential non-target species present in the receiving environment of a GM crop. While risk assessment must be rigorous, new approaches are necessary to improve the efficiency of the process. Utilisation of published information and existing data on the phenology and population dynamics of test species in the field can be combined with limited amounts of experimental biosafety data to predict possible outcomes on species persistence. This paper presents an example of an approach where data from laboratory experiments and field studies on phenology are combined using predictive modelling. Using the New Zealand native weevil species Nicaeana cervina as a case study, we could predict that oviposition rates of the weevil feeding on a GM ryegrass could be reduced by up to 30% without threat to populations of the weevil in pastoral ecosystems. In addition, an experimentally established correlation between feeding level and oviposition led to the prediction that a consistent reduction in feeding of 50% or higher indicated a significant risk to the species and could potentially lead to local extinctions. This approach to biosafety risk assessment, maximising the use of pre-existing field and laboratory data on non-target species, can make an important contribution to informed decision-making by regulatory authorities and developers of new technologies.

Environmental …, 2007

Effects of tobacco genetically modified to express the protease inhibitor bovine spleen trypsin i... more Effects of tobacco genetically modified to express the protease inhibitor bovine spleen trypsin inhibitor (BSTI) were examined in laboratory assays against three earthworm and one collembolan species. BSTI is a serine protease inhibitor that can bind to the digestive ...

New Zealand Plant Protection

Little is known about the impacts of transgenic plants and microorganisms on soil biota and proce... more Little is known about the impacts of transgenic plants and microorganisms on soil biota and processes despite the large number of field releases of transgenic crops Recent work has shown that transgenic plants can cause changes in the soil biota (both invertebrates and microorganisms) associated with these plants Often the changes are transient but their impact on the soil ecosystem remains unknown Horizontal gene transfer from genetically modified (GM) bacteria to indigenous soil bacteria has been demonstrated but movement of genes from transgenic plants if it occurs at all has not yet been detected in natural systems Soil invertebrates appear to play an important role in horizontal gene transfer between bacteria in soil

New Zealand Plant Protection

A granular formulation of Serratia entomophila has been developed to improve shelflife and storag... more A granular formulation of Serratia entomophila has been developed to improve shelflife and storage characteristics of this bacterium which is used as a microbial control agent of the New Zealand grass grub Bacterial establishment and survival of bacteria released from the granular and liquid formulations were assessed in a laboratory experiment Bacteria were enumerated by dilution plating onto Serratia selective agar Serratia entomophila populations in soil inoculated with granules remained stable in soil for up to five months at a range of soil moisture levels Bacterial numbers declined more rapidly when soil was inoculated with the liquid formulation High numbers of bacteria remained viable in the granules throughout the experiment demonstrating the potential for sustained release of inoculum after application of the biopesticide granules

New Zealand Plant Protection

New Zealand Plant Protection

Biopesticides can provide effective control of existing and invasive invertebrate pests and disea... more Biopesticides can provide effective control of existing and invasive invertebrate pests and diseases impacting on New Zealands primary sector production and combat new pests emerging as a result of landuse change farming intensification and climate change While the international biopesticide market is undergoing rapid growth at present assisted by regulatory environments favourable to biopesticide registration and uptake biopesticides are not widely used in New Zealand The number of biopesticides registered under the Agriculture Compounds and Veterinary Medicines Act (Ministry for Primary Industries MPI) has slowly increased from 11 products in 1991 to 33 in 2010 with 49 registered in 2015 However only a limited number of these products are actively marketed and used by growers at present To play an increasing role in New Zealands sustainable production systems next generation biopesticides will need to have levels of efficacy comparable to currently available controls and will be a...

Recent studies implicate biochar as a potential nitrous oxide mitigation agent as weU as a carbon... more Recent studies implicate biochar as a potential nitrous oxide mitigation agent as weU as a carbon sink. The objectives ofth;s study were to: (1) Investigate the ability of biochar to reduce emissions of nitrous oxide (N 2 0) from bovine urine-treated cores packed with a Wakanui silt loam (2) Determine the extent to which shifts in total and active bacterial and archaeal ammonia oxidizer communities in these soil cores explain observed N-turnover.