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Composting is an effective strategy to process agricultural and urban waste into forms that may be beneficial to crops. The objectives of this orchard field study were to characterize how a dairy manure compost and a food waste compost influenced: (1) soil nitrogen and carbon pools, (2) bacterial and nematode soil food webs and (3) tree growth and leaf N. The effects of composts were compared with fertilized and unfertilized control plots over two years in a newly planted almond orchard. Both dairy manure compost and food waste compost increased soil organic matter pools, as well as soil nitrate and ammonium at certain time points. Both composts also distinctly altered bacterial communities after application, specifically those groups with carbon degrading potential, and increased populations of bacterial feeding nematodes, although in different timeframes. Unique correlations were observed between nematode and bacterial groups within compost treatments that were not present in controls. Food waste compost increased trunk diameters compared to controls and had greater relative abundance of herbivorous root tip feeding nematodes. Results suggest that recycled waste composts contribute to biologically based nitrogen cycling and can increase tree growth, mainly within the first year after application.
Amanda K. Hodson; Jordan M. Sayre; Maria C.C.P. Lyra; Jorge L. Mazza Rodrigues. Influence of Recycled Waste Compost on Soil Food Webs, Nutrient Cycling and Tree Growth in a Young Almond Orchard. Agronomy 2021, 11, 1745 .
AMA StyleAmanda K. Hodson, Jordan M. Sayre, Maria C.C.P. Lyra, Jorge L. Mazza Rodrigues. Influence of Recycled Waste Compost on Soil Food Webs, Nutrient Cycling and Tree Growth in a Young Almond Orchard. Agronomy. 2021; 11 (9):1745.
Chicago/Turabian StyleAmanda K. Hodson; Jordan M. Sayre; Maria C.C.P. Lyra; Jorge L. Mazza Rodrigues. 2021. "Influence of Recycled Waste Compost on Soil Food Webs, Nutrient Cycling and Tree Growth in a Young Almond Orchard." Agronomy 11, no. 9: 1745.
Economically damaging populations of lesion nematode and ring nematode are managed in tree crops largely through pre-plant chemical fumigation, the use of which is increasingly restricted due to human health and environmental concerns. Reducing the use of fumigants requires precise knowledge of pest nematodes’ density and distribution, however; extensive sampling is costly due to the time intensive process of nematode counting and identification. In this study, species specific primers were designed and real time PCR (qPCR) assays developed separately for both species of nematodes. The assays successfully detected each species and did not show significant amplification of non-target nematode groups. Both assays related well with microscopic counts of prepared solutions of nematodes, as well as solutions extracted from field samples. Such high-throughput molecular quantification could reduce diagnostic costs, allowing a more accurate picture of nematode populations in the field.
Amanda Kaye Hodson; Andrew Cicchetto; Fernando Antonio Fierro. Real time PCR assays to detect and quantify the nematodes Pratylenchus vulnus and Mesocriconema xenoplax. Crop Protection 2021, 145, 105617 .
AMA StyleAmanda Kaye Hodson, Andrew Cicchetto, Fernando Antonio Fierro. Real time PCR assays to detect and quantify the nematodes Pratylenchus vulnus and Mesocriconema xenoplax. Crop Protection. 2021; 145 ():105617.
Chicago/Turabian StyleAmanda Kaye Hodson; Andrew Cicchetto; Fernando Antonio Fierro. 2021. "Real time PCR assays to detect and quantify the nematodes Pratylenchus vulnus and Mesocriconema xenoplax." Crop Protection 145, no. : 105617.
As an alternative to chemical fertilizers, growers routinely apply organic amendments to provide crop nutrition, but lack information on which combinations best increase nitrogen (N) availability rates and stimulate beneficial soil micro-organisms. The objectives of this study were to characterize how organic amendments and amendment combinations influenced 1) bacterial communities, 2) nematode communities and 3) N availability and plant growth. Dry amendments (pelleted poultry manure and compost) and liquid amendments (fish hydrolysate and food hydrolysate), were tested alone and combined in laboratory incubations and a greenhouse experiment. Pelleted poultry manure caused rapid increases of bacterial taxa associated with N cycling such as Nitrosospira, Pseudomonas, Pseudoxanthomonas and Flavobacterium as well as increases in opportunistic bacterial feeding nematodes such as Panagrolaimus. The abundance of many bacterial taxa, including some N cyclers, showed strong relationships with nematode genera and nematode indices of nutrient processing. Compost increased the prevalence of bacteria such as Chryseolinea, Sporocytophaga and Phenylobacterium, which are known to degrade complex C-compounds. Both liquid amendments caused slight changes in microbial communities. While pelleted poultry manure resulted in the highest net N availability and greatest plant growth compared to controls, compost reduced plant growth unless combined with liquid amendments. Results suggest that C:N ratio and C complexity influence nematode and bacterial community compositions as well as N availability, with implications for optimizing biologically based N cycling.
Janina Milkereit; Daniel Geisseler; Patricia Lazicki; Matthew L. Settles; Blythe P. Durbin-Johnson; Amanda Hodson. Interactions between nitrogen availability, bacterial communities, and nematode indicators of soil food web function in response to organic amendments. Applied Soil Ecology 2020, 157, 103767 .
AMA StyleJanina Milkereit, Daniel Geisseler, Patricia Lazicki, Matthew L. Settles, Blythe P. Durbin-Johnson, Amanda Hodson. Interactions between nitrogen availability, bacterial communities, and nematode indicators of soil food web function in response to organic amendments. Applied Soil Ecology. 2020; 157 ():103767.
Chicago/Turabian StyleJanina Milkereit; Daniel Geisseler; Patricia Lazicki; Matthew L. Settles; Blythe P. Durbin-Johnson; Amanda Hodson. 2020. "Interactions between nitrogen availability, bacterial communities, and nematode indicators of soil food web function in response to organic amendments." Applied Soil Ecology 157, no. : 103767.
Summary Fumigants, such as 1,3-dichloropropene and chloropicrin, have become key to pre-plant pest management in almond production. Whilst the use of these fumigants has become increasingly restricted due to human health concerns, less is known about their below-ground non-target effects in orchards and how nematode communities recover from fumigation over time. In this study, replicated trials compared 1,3-dichloropropene + chloropicrin to non-treated controls in two almond orchards in California, USA. Nematode communities, nematode indices and nematode metabolic footprints were quantified soon after fumigation and for 2 years afterwards. Fumigation reduced the Herbivore Metabolic Footprint in year 1, and populations of Pratylenchus vulnus in year 3. Fumigation also reduced populations of larger omnivores and predators, resulting in lower levels of the Structure Index at one site. Populations of fungal-feeding nematodes were more adversely affected by fumigation than bacterial-feeding nematode populations. At both sites, fumigation still influenced nematode community composition 2 years after treatment application.
Amanda K. Hodson; Janina Milkereit; Gavin C. John; David A. Doll; Roger A. Duncan. The effect of fumigation on nematode communities in California almond orchards. Nematology 2019, 21, 899 -912.
AMA StyleAmanda K. Hodson, Janina Milkereit, Gavin C. John, David A. Doll, Roger A. Duncan. The effect of fumigation on nematode communities in California almond orchards. Nematology. 2019; 21 (9):899-912.
Chicago/Turabian StyleAmanda K. Hodson; Janina Milkereit; Gavin C. John; David A. Doll; Roger A. Duncan. 2019. "The effect of fumigation on nematode communities in California almond orchards." Nematology 21, no. 9: 899-912.
A greater understanding of the ecological relationships between Pacific spider mite, Tetranychus pacificus, and its almond host is needed for better management recommendations and reduced need for pesticides. Since populations of T. pacificus are thought to increase with deficit irrigation and fertilization, they may also differ between almond cultivars varying in leaf traits relating to water use and leaf nitrogen (N) content. In the current study, the relationships between T. pacificus populations, almond cultivars and leaf traits were examined at studies in two locations. In the first study, a large-scale cultivar trial with a high level of T. pacificus infestation, spider mite eggs were more common on the cultivar ‘Sweetheart’ than either ‘Nonpareil’ or ‘Marcona,’ and across all cultivars, mites and leaf damage increased with stomatal density, but decreased with stomatal length. Almond cultivars differed in traits, with ‘Sweetheart’ having the highest leaf N and ‘Marcona’ the lowest stomatal density. In the second study, a germplasm repository orchard collection with low levels of T. pacificus infestation, spider mites were not detected on the cultivar ‘Mission’ but were similarly highest on ‘Sweetheart.’ Mites increased with N across all cultivars, and leaf damage due to spider mites increased with more negative δ13C, indicating low water use efficiency. Results suggest that monitoring of spider mite populations should include conditions of high nutrient and water availability, especially for susceptible cultivars, and that spider mite populations are not consistently higher with leaf traits indicating water stress.
A. K. Hodson; B. D. Lampinen. Effects of cultivar and leaf traits on the abundance of Pacific spider mites in almond orchards. Arthropod-Plant Interactions 2018, 13, 453 -463.
AMA StyleA. K. Hodson, B. D. Lampinen. Effects of cultivar and leaf traits on the abundance of Pacific spider mites in almond orchards. Arthropod-Plant Interactions. 2018; 13 (3):453-463.
Chicago/Turabian StyleA. K. Hodson; B. D. Lampinen. 2018. "Effects of cultivar and leaf traits on the abundance of Pacific spider mites in almond orchards." Arthropod-Plant Interactions 13, no. 3: 453-463.
The Coast Range mountains in California (CA), USA, may harbor remnant communities of soil biota that no longer occur in the intensively-managed agricultural valleys nearby. Relationships between nematode communities, riparian vegetation, soil carbon (C) and nitrogen (N) pools, and other soil properties were studied at a reserve managed for biodiversity conservation. Differences between riparian habitats were assessed using nematode community identification and metabolic footprint analysis (a method that evaluates ecosystem functioning based on nematode biomass). Nematode communities and metabolic footprints were compared across 12 riparian sites. Those from the sites with evergreen shrubs had high levels of predators but few prey while communities from under deciduous trees were more metabolically balanced, with high levels of both predators and prey. To examine how leaf functional traits affected nematode community structure, metabolic footprints, and soil C and N pools, a second study focused on two riparian woodland sites. Bacterivore and predator metabolic footprints increased with proximity to the creek-bank, where deciduous trees were prevalent. Leaf litter C:N ratio, soil C:N ratio, and the ratio of predators:prey also varied with plant functional traits. Both the complexity of the nematode communities and soil C storage were higher than in previous studies conducted along riparian corridors within intensive agriculture. In these relatively undisturbed areas, stream hydrology has created a patchy distribution of soil texture classes and woody plant species, which in turn, has resulted in diverse nematode assemblages and soil food webs associated with high levels of soil organic matter.
Amanda K. Hodson; Howard Ferris; Allan D. Hollander; Louise E. Jackson. Nematode food webs associated with native perennial plant species and soil nutrient pools in California riparian oak woodlands. Geoderma 2014, 228-229, 182 -191.
AMA StyleAmanda K. Hodson, Howard Ferris, Allan D. Hollander, Louise E. Jackson. Nematode food webs associated with native perennial plant species and soil nutrient pools in California riparian oak woodlands. Geoderma. 2014; 228-229 ():182-191.
Chicago/Turabian StyleAmanda K. Hodson; Howard Ferris; Allan D. Hollander; Louise E. Jackson. 2014. "Nematode food webs associated with native perennial plant species and soil nutrient pools in California riparian oak woodlands." Geoderma 228-229, no. : 182-191.
The natural history of many entomopathogenic nematode species remains unknown, despite their wide commercial availability as biological control agents. The ambushing entomopathogenic nematode, Steinernema carpocapsae, and the introduced European earwig, Forficula auricularia, forage on the soil surface. Since they likely encounter one another in nature, we hypothesized that earwigs are susceptible to nematode infection. In the laboratory, the LC(50) for F. auricularia was 226 S. carpocapsae/earwig and the reproductive potential was 123.5 infective juvenile nematodes/mg tissue. This susceptibility depended on host body size with significantly higher mortality rates seen in larger earwigs. In a study of host recognition behavior, S. carpocapsae infective juveniles responded to earwig cuticle as strongly as they did to Galleria mellonella cuticle. We also found that earwigs exposed to S. carpocapsae cleaned and scratched their front, middle and back legs significantly more than controls. Coupled with previous field data, these findings lead us to suggest that F. auricularia may be a potential host for S. carpocapsae.
A.K. Hodson; M.L. Friedman; L.N. Wu; E.E. Lewis. European earwig (Forficula auricularia) as a novel host for the entomopathogenic nematode Steinernema carpocapsae. Journal of Invertebrate Pathology 2011, 107, 60 -64.
AMA StyleA.K. Hodson, M.L. Friedman, L.N. Wu, E.E. Lewis. European earwig (Forficula auricularia) as a novel host for the entomopathogenic nematode Steinernema carpocapsae. Journal of Invertebrate Pathology. 2011; 107 (1):60-64.
Chicago/Turabian StyleA.K. Hodson; M.L. Friedman; L.N. Wu; E.E. Lewis. 2011. "European earwig (Forficula auricularia) as a novel host for the entomopathogenic nematode Steinernema carpocapsae." Journal of Invertebrate Pathology 107, no. 1: 60-64.
Roy Kaspi; Andrew Ross; Amanda K. Hodson; Glen N. Stevens; Harry K. Kaya; Edwin E. Lewis. Foraging efficacy of the entomopathogenic nematode Steinernema riobrave in different soil types from California citrus groves. Applied Soil Ecology 2010, 45, 243 -253.
AMA StyleRoy Kaspi, Andrew Ross, Amanda K. Hodson, Glen N. Stevens, Harry K. Kaya, Edwin E. Lewis. Foraging efficacy of the entomopathogenic nematode Steinernema riobrave in different soil types from California citrus groves. Applied Soil Ecology. 2010; 45 (3):243-253.
Chicago/Turabian StyleRoy Kaspi; Andrew Ross; Amanda K. Hodson; Glen N. Stevens; Harry K. Kaya; Edwin E. Lewis. 2010. "Foraging efficacy of the entomopathogenic nematode Steinernema riobrave in different soil types from California citrus groves." Applied Soil Ecology 45, no. 3: 243-253.