scholarly journals Field Evaluation of Reduced Rate Brassicaceae Seed Meal Amendment and Rootstock Genotype on the Microbiome and Control of Apple Replant Disease

2019 ◽  
Vol 109 (8) ◽  
pp. 1378-1391 ◽  
Author(s):  
Likun Wang ◽  
Mark Mazzola

An orchard field trial was conducted to assess the utility of reduced rate Brassicaceae seed meal (SM) amendment in concert with specific rootstock genotypes for effective control of apple replant disease. Three amendment rates of a 1:1 formulation of Brassica juncea-Sinapis alba SM were compared with preplant 1,3-dichloropropene/chloropicrin soil fumigation for disease control efficacy. When applied at the highest rate (6.6 t ha−1) in the spring of planting, SM caused significant phytotoxicity and tree mortality, which was higher for Gala/M.26 than for Gala/G.41 but was not observed at SM application rates of 2.2 or 4.4 t ha−1. SM treatment resulted in growth and yield increases of Gala/M.26 and Gala/G.41 trees in a manner similar to the fumigation treatment and significantly greater than the no treatment control. Tree growth in soils treated with SM at 4.4 t ha−1 was similar or superior to that obtained with SM at 6.6 t ha−1 and superior to that attained at an SM application rate of 2.2 t ha−1. Soil fumigation and all SM treatments reduced Pratylenchus penetrans root infestation relative to the control treatment at the end of the initial growing season. Lesion nematode root densities in the fumigation treatment, but not SM treatments, rapidly recovered and were indistinguishable from the control at the end of the second growing season. Soil fumigation and all SM treatments significantly suppressed Pythium spp. root infection relative to the control. Trees grafted to rootstock G.41 possessed lower P. penetrans root densities relative to trees grafted to rootstock M.26. One year after planting, composition of microbial communities from SM-amended soils was distinct from those detected in control and fumigated soils, and the differences were amplified with increasing SM application rate. Specific fungal and bacterial phyla associated with suppression of plant pathogens were more abundant in SM-treated soil relative to the control, and they were similar in abundance in 4.4- and 6.6-t ha−1 SM treatments. Findings from this study demonstrated that use of the appropriate apple rootstock genotype will allow for effective replant disease control at SM application rates significantly less than that utilized previously (6.6 t ha−1).

2019 ◽  
Vol 109 (4) ◽  
pp. 607-614 ◽  
Author(s):  
Likun Wang ◽  
Mark Mazzola

Preplant soil application of a Brassica juncea–Sinapis alba seed meal formulation (SM) at a rate of 6.6 t ha−1 alters composition of the orchard soil microbiome in a manner that yields sustainable long-term suppression of soilborne pathogens in apple production systems. However, the cost of SM amendment has hindered the adoption of this tactic to manage apple replant disease in commercial orchards. Greenhouse trials were conducted to assess the effect of reduced SM application rates in concert with apple rootstock genotype on structure of the rhizosphere microbiome and associated disease control outcomes. At all application rates assessed, SM treatment increased tree growth and reduced disease development relative to the control. In general, total tree biomass and leader shoot length were similar in soils treated with SM at 4.4 or 6.6 t ha−1 regardless of rootstock genotype. Equivalent increase in tree biomass when cultivated in soil treated at the lowest and highest SM amendment rate was attained when used in conjunction with G.41 or G.210 apple rootstocks. Suppression of Pythium spp. or Pratylenchus penetrans root densities was similar at all SM application rates. When cultivated in nontreated replant orchard soil, Geneva rootstocks (G.41 and G.210) exhibited lower levels of Pythium spp. and P. penetrans root colonization relative to Malling rootstocks (M.9 and MM.106). For a given rootstock, structure of the rhizosphere microbiome was similar in soils treated with SM at 4.4 and 6.6 t ha−1. G.41 and G.210 rootstocks but not M.9 or MM.106 cultivated in soil treated with SM at 2.2 t ha−1 possessed a rhizosphere bacterial community structure that differed significantly from the control. Findings indicate that effective control of apple replant disease may be attained at lower SM amendment rates than employed previously, with lower effective rates possible when integrated with tolerant rootstock genotypes such as G.41 or G.210.


Plant Disease ◽  
2010 ◽  
Vol 94 (7) ◽  
pp. 835-842 ◽  
Author(s):  
Mark Mazzola ◽  
Jack Brown

The efficacy of brassicaceous seed meals for the control of apple replant disease and the effects of such treatments on the causal pathogen complex were examined in conventional and organic production systems. When used in conjunction with a postplant application of mefenoxam, Brassica juncea and Sinapis alba seed meal soil amendments were as effective as preplant fumigation of soil with 1,3-dichloropropene-chloropicrin in terms of disease control, tree growth, and overall fruit yields of Gala/M26. Brassica napus seed meal amendment–mefenoxam soil drench also enhanced yields in a manner comparable to preplant fumigation, but vegetative growth was intermediate between the control and fumigation treatments. When applied alone, seed meal amendments failed to enhance tree growth or control disease to the level attained in response to soil fumigation. Postplant mefenoxam treatments revealed that failure of seed meal amendments to enhance tree growth and yield when used independently was due, at least in part, to increased apple root infection by Pythium spp. in B. napus and S. alba seed meal–amended soils, and by Phytophthora cambivora in B. juncea–amended soil. As mefenoxam treatment is not compatible with organic cropping systems, a seed meal blend was formulated which, based upon biological activity, was predicted to suppress known components of the target pathogen complex without need of additional treatment. Gala/M26 trees planted in soils treated with a 1:1 ratio of B. juncea:B. napus seed meal blend performed as well in terms of disease control and vegetative growth as trees cultivated in fumigated soil at an organic-certified orchard. Because these trials utilized the highly susceptible rootstock M26, the results demonstrate that these amendments are a viable alternative to soil fumigation for the control of apple replant disease in both conventional and organic systems.


Plant Disease ◽  
2005 ◽  
Vol 89 (11) ◽  
pp. 1207-1213 ◽  
Author(s):  
Mark Mazzola ◽  
Kent Mullinix

Alternative management strategies to the use of preplant soil fumigation for the control of apple replant disease (ARD), including cover crops and strategies incorporating Brassica napus seed meal (rape seed meal [RSM]) amendment as the central component, were evaluated in the orchard. A 1-year wheat cover crop consisting of three short-term cropping periods with plant material removed at the end of each growth period and a 3-year B. napus green manure significantly enhanced vegetative growth and yield of Gala/M26. However, in each instance, the resulting disease control and growth response were inferior to that achieved through preplant methyl bromide soil fumigation. A 3-year bare fallow and 1- or 2-year B. napus green manure neither suppressed disease development nor enhanced tree growth. Preplant RSM amendment in conjunction with a postplant mefenoxam soil drench provided effective suppression of ARD, and the resulting tree growth and yield were comparable with that attained in response to 1,3- dichloropropene-chloropicrin fumigation in one orchard. At a second orchard, the growth response attained with the alternative treatment was inferior to preplant soil fumigation, which was associated with an apparent re-infestation of RSM-treated soils and tree roots by Pratylenchus spp. Application of RSM after wheat cropping or in conjunction with soil solarization provided an intermediate level of disease control and a corresponding reduction in growth and yield of apple relative to preplant fumigation at both sites.


2015 ◽  
Vol 105 (4) ◽  
pp. 460-469 ◽  
Author(s):  
Mark Mazzola ◽  
Shashika S. Hewavitharana ◽  
Sarah L. Strauss

Brassicaceae seed meal (SM) formulations were compared with preplant 1,3-dichloropropene/chloropicrin (Telone-C17) soil fumigation for the ability to control apple replant disease and to suppress pathogen or parasite reinfestation of organic orchard soils at two sites in Washington State. Preplant soil fumigation and an SM formulation consisting of either Brassica juncea–Sinapis alba or B. juncea–B. napus each provided similar levels of disease control during the initial growing season. Although tree growth was similar in fumigated and SM-amended soil during the initial growing season, tree performance in terms of growth and yield was commonly superior in B. juncea–S. alba SM-amended soil relative to that in fumigated soil at the end of four growing seasons. SM-amended soils were resistant to reinfestation by Pratylenchus penetrans and Pythium spp. relative to fumigated soils and corresponded with enhanced tree performance. Phytotoxic symptoms were observed in response to SM amendment at one of two orchard sites, were dependent upon season of application, and occurred in an SM formulation-specific manner. After 2 years, the rhizosphere microbiome in fumigated soils had reverted to one that was indistinguishable from the no-treatment control. In contrast, rhizosphere soils from the SM treatment possessed unique bacterial and fungal profiles, including specific microbial elements previously associated with suppression of plant-pathogenic fungi, oomycetes, and nematodes. Overall diversity of the microbiome was reduced in the SM treatment rhizosphere, suggesting that enhanced “biodiversity” was not instrumental in achieving system resistance or pathogen suppression.


2010 ◽  
Vol 28 (2) ◽  
pp. 81-84
Author(s):  
A.K. Hagan ◽  
J.R. Akridge ◽  
K.L. Bowen

Abstract Efficacy of Heritage 50WG (azoxystrobin) over a range of application rates and treatment intervals was compared with Daconil Weather Stik 6F (chlorothalonil) and Eagle 40W (myclobutanil) for the control of Alternaria leaf spot (Alternaria tagetica) in a simulated landscape planting of marigold in southwest Alabama. When applied at 2-week intervals, all rates of Heritage 50WG gave better disease control in all four years than Daconil Weather Stik 6F or Eagle 40W, applied on the same schedule. In two of three years, weekly applications of Daconil Weather Stik 6F decreased Alternaria leaf spot severity compared with the non-fungicide treated control, but when applied at 2-week intervals, disease levels were similar to the non-fungicide treated control in two of four years. Typically, Alternaria leaf spot intensified when Heritage 50WG application rates declined from 0.16 to 0.04 g ai·liter−1 and treatment intervals increased from 2-to 4-weeks. At the 0.04 g ai·liter−1 rate of Heritage 50WG, disease control was usually better at the 2-than at the 3-and, particularly, 4-week treatment schedule. Regardless of the level of disease pressure, Heritage 50WG at 0.08 and 0.16 g ai·liter−1 when applied at 3-week intervals consistently gave effective control of Alternaria leaf spot on marigold.


2020 ◽  
Vol 66 (No. 9) ◽  
pp. 468-476
Author(s):  
Miroslav Jursík ◽  
Martin Kočárek ◽  
Michaela Kolářová ◽  
Lukáš Tichý

Six sunflower herbicides were tested at two application rates (1N and 2N) on three locations (with different soil types) within three years (2015–2017). Efficacy of the tested herbicides on Chenopodium album increased with an increasing cation exchange capacity (CEC) of the soil. Efficacy of pendimethalin was 95%, flurochloridone and aclonifen 94%, dimethenamid-P 72%, pethoxamid 49% and S-metolachlor 47%. All tested herbicides injured sunflower on sandy soil (Regosol) which had the lowest CEC, especially in wet conditions (phytotoxicity 27% after 1N application rate). The highest phytotoxicity was recorded after the application of dimethenamid-P (19% at 1N and 45% at 2N application rate). Main symptoms of phytotoxicity were leaf deformations and necroses and the damage of growing tips, which led to destruction of some plants. Aclonifen, pethoxamid and S-metolachlor at 1N did not injure sunflower on the soil with the highest CEC (Chernozem) in any of the experimental years. Persistence of tested herbicides was significantly longer in Fluvisol (medium CEC) compared to Regosol and Chernozem. Dimethenamid-P showed the shortest persistence in Regosol and Chernozem. The majority of herbicides was detected in the soil layer 0–5 cm in all tested soils. Vertical transport of herbicides in soil was affected by the herbicide used, soil type and weather conditions. The highest vertical transport was recorded for dimethenamid-P and pethoxamid (4, resp. 6% of applied rate) in Regosol in the growing season with high precipitation.  


2021 ◽  
Vol 9 (4) ◽  
pp. 763
Author(s):  
Likun Wang ◽  
Tracey S. Somera ◽  
Heidi Hargarten ◽  
Loren Honaas ◽  
Mark Mazzola

Brassicaceae seed meal (SM) soil amendment has been utilized as an effective strategy to control the biological complex of organisms, which includes oomycetes, fungi, and parasitic nematodes, that incites the phenomenon termed apple replant disease. Soil-borne disease control attained in response to Brassicaceae SM amendment is reliant on multiple chemical and biological attributes, including specific SM-generated modifications to the soil/rhizosphere microbiome. In this study, we conducted a comparative analyses of apple root gene expression as influenced by rootstock genotype combined with a seed meal (SM) soil amendment. Apple replant disease (ARD) susceptible (M.26) and tolerant (G.210) rootstocks cultivated in SM-amended soil exhibited differential gene expression relative to corresponding non-treated control (NTC) orchard soil. The temporal dynamics of gene expression indicated that the SM-amended soil system altered the trajectory of the root transcriptome in a genotype-specific manner. In both genotypes, the expression of genes related to plant defense and hormone signaling were altered in SM-amended soil, suggesting SM-responsive phytohormone regulation. Altered gene expression was temporally associated with changes in rhizosphere microbiome density and composition in the SM-treated soil. Gene expression analysis across the two rootstocks cultivated in the pathogen-infested NTC soil showed genotype-specific responses indicative of different defensive strategies. These results are consistent with previously described resistance mechanisms of ARD “tolerant” rootstock cultivars and also add to our understanding of the multiple mechanisms by which SM soil amendment and the resulting rhizosphere microbiome affect apple rootstock physiology. Future studies which assess transcriptomic and metagenomic data in parallel will be important for illuminating important connections between specific rhizosphere microbiota, gene-regulation, and plant health.


1983 ◽  
Vol 5 (3) ◽  
pp. 177-180 ◽  
Author(s):  
R. G. Ross ◽  
R. W. Delbridge ◽  
J. Kimpinski ◽  
K. B. McRae

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