scholarly journals Reduction of Landscape Pathogens in Florida by Soil Solarization

Plant Disease ◽  
2002 ◽  
Vol 86 (12) ◽  
pp. 1388-1395 ◽  
Author(s):  
R. J. McGovern ◽  
R. McSorley ◽  
M. L. Bell
Keyword(s):  
Biological Control ◽  
Crown Rot ◽  
Soil Solarization ◽  
Shoot Biomass ◽  
Infested Soil ◽  
Pseudomonas Chlororaphis ◽  
Biological Control Agents ◽  
Central Florida ◽  
Air Space ◽  
Polyethylene Mulch

Two experiments were conducted during autumn 1997 and 1998 in west-central Florida to evaluate the effectiveness of soil solarization alone and in combination with the biological control agents Streptomyces lydicus (Actinovate) and Pseudomonas chlororaphis (syn. P. aureofasciens, AtEze) and the reduced-risk fungicide fludioxonil (Medallion) in managing soilborne pathogens of impatiens (Impatiens × wallerana, ‘Accent Burgundy’). Naturally infested soil was solarized for 47 or 48 days during September and October using two layers of 25-μm clear, low-density polyethylene mulch, separated by an air space of up to 7.5 cm. Solarization decreased the final incidence and progress of Rhizoctonia crown rot and blight, incidence of Pythium spp. in roots, and root discoloration, and increased shoot biomass in both experiments. The technique also consistently reduced root-knot severity and population densities of Meloidogyne incognita, Dolichodorus heterocephalus, Paratrichodorus minor, and Criconemella spp. The incidence of Rhizoctonia crown rot and blight was reduced by fludioxonil, but not by the biological control agents.

Lysis and biological control of Aspergillus niger by Bacillus subtilis AF 1

1996 ◽  
Vol 42 (6) ◽  
pp. 533-538 ◽  
Author(s):  
A. R. Podile ◽  
A. P. Prakash
Keyword(s):  
Biological Control ◽  
Bacillus Subtilis ◽  
Aspergillus Niger ◽  
Fungal Growth ◽  
Dry Weight ◽  
Crown Rot ◽  
Fungal Mycelium ◽  
Infested Soil ◽  
Dual Culture ◽  
Bacterial Cells

A biocontrol rhizobacterial strain of Bacillus subtilis AF 1 grown for 6 h was coinoculated with Aspergillus niger at different time intervals and microscopic observations revealed adherence of bacterial cells to the fungal mycelium. Bacterial cells multiplied in situ and colonized the mycelial surface. Growth of AF 1 resulted in damage to the cell wall, followed by lysis. AF 1 inoculation into media containing A. niger at 0, 6, and 12 h suppressed >90% fungal growth, while in 18- and 24-h cultures fungal growth inhibition was 70 and 56%, respectively, in terms of dry weight. In dual culture the fungal growth was not accompanied by formation of spores. The mycelial preparation of A. niger as principal carbon source supported the growth of B. subtilis, as much as chitin. Extracellular protein precipitate from B. subtilis culture filtrate had a significant growth-retarding effect on A. niger. Groundnut seeds bacterized with B. subtilis showed a reduced incidence of crown rot in A. niger infested soil, suggesting a possible role of B. subtilis in biological control of A. niger.Key words: mycolytic bacteria, Bacillus subtilis, Aspergillus niger, biological control.

scholarly journals Efficacy of Biological and Chemical Treatments for Control of Fusarium Root and Stem Rot on Greenhouse Cucumber

Plant Disease ◽  
2003 ◽  
Vol 87 (12) ◽  
pp. 1462-1470 ◽  
Author(s):  
S. Rose ◽  
M. Parker ◽  
Z. K. Punja
Keyword(s):  
Biological Control ◽  
The Other ◽  
Stem Rot ◽  
Pseudomonas Chlororaphis ◽  
Block Medium ◽  
Biological Control Agents ◽  
Seedling Mortality ◽  
Severity Of Disease ◽  
Greenhouse Cucumber ◽  
Rock Wool

Potential disease control methods were evaluated against root and stem rot of cucumber (Cucumis sativus) caused by Fusarium oxysporum f. sp. radicis-cucumerinum. Crab/shrimp shell chitin; three composted media; the biological control agents Pseudomonas chlororaphis strain 63-28, Trichoderma harzianum (RootShield Drench), Streptomyces griseoviridis (Mycostop), Gliocladium catenulatum (Prestop WP, Prestop Mix), and Trichoderma (Gliocladium) virens (SoilGard); and the fungicides thiram or benomyl were added at seeding time followed by inoculation with the pathogen. The addition of chitin (4%, vol/vol) to a peat-based medium significantly (P ≤ 0.05) enhanced seedling growth, increased soil pH, and reduced F. oxysporum f. sp. radicis-cucumerinum populations, but the severity of disease was increased. The addition of composted media (greenhouse compost, windrow composted dairy solids, and vermi-composted dairy solids) to the seeding cavity in a rock wool block medium, followed 48 h later by inoculation with F. oxysporum f. sp. radicis-cucumerinum, reduced seedling mortality when measured after 37 days. Greenhouse compost was significantly (P ≤ 0.05) more suppressive than the other two composts, and the suppression was partially eliminated by sterilization of the compost. The biological control agent G. catenulatum (formulated as Prestop WP and Prestop Mix) significantly reduced seedling mortality when it was applied at seeding 24 h prior to inoculation with the pathogen in the rock wool block medium. None of the other biological control agents reduced disease incidence when compared with control plants under these experimental conditions. Pseudomonas chlororaphis and the fungicide thiram both significantly reduced plant mortality at 17 and 24°C when pathogen-infested seed was treated, or when bacteria-treated and fungicide-treated seed were planted into pathogen-infested peat medium at 24°C. Under semicommercial propagation conditions, treatments consisting of Prestop WP, RootShield Drench, My-costop, and windrow composted dairy solids reduced the severity of disease caused by F. oxysporum f. sp. radicis-cucumerinum in two out of three trials. The efficacy of the biological control agents was affected by seasonal differences in growing conditions, which affected the incidence and severity of the disease. The results from this study indicate that several different approaches can be used at seeding to control Fusarium root and stem rot on greenhouse cucumber.

scholarly journals Reduction of Phytophthora Blight of Madagascar Periwinkle in Florida by Soil Solarization in Autumn

Plant Disease ◽  
2000 ◽  
Vol 84 (2) ◽  
pp. 185-191 ◽  
Author(s):  
R. J. McGovern ◽  
R. McSorley ◽  
R. R. Urs
Keyword(s):  
Field Experiments ◽  
Phytophthora Nicotianae ◽  
Soil Solarization ◽  
Low Density Polyethylene ◽  
Wheat Seed ◽  
Phytophthora Blight ◽  
Population Densities ◽  
Madagascar Periwinkle ◽  
Central Florida ◽  
Polyethylene Mulch

Three field experiments were conducted in southwest and west-central Florida in 1993 through 1995 to evaluate the effectiveness of soil solarization during autumn in reducing Phytophthora blight of Madagascar periwinkle (Catharanthus roseus) caused by Phytophthora nicotianae. Plots (3.6 by 3.6 m) were infested by incorporating winter wheat seed containing P. nicotianae in the upper 15 cm of soil. Solarization was then conducted for 21 to 41 days, primarily during October, using clear, 25- or 50-μm low-density polyethylene mulch. The progress of Phytophthora blight, monitored for 31 to 42 days following planting, was significantly reduced by solarization in all experiments, and final blight incidence was reduced in two of three experiments. Solarization also reduced population densities of P. nicotianae.

Diversity of the bacterial hyperparasite Pasteuria penetrans in relation to root-knot nematodes (Meloidogyne spp.) control on Acacia holosericea

Nematology ◽  
2000 ◽  
Vol 2 (4) ◽  
pp. 435-442 ◽  
Author(s):  
Robin Duponnois ◽  
Jean Thioulouse ◽  
Mireille Fargette ◽  
Keith Davies ◽  
Sabine Fould
Keyword(s):  
Biological Control ◽  
Shoot Biomass ◽  
Biological Control Agents ◽  
Substantial Variation ◽  
Pasteuria Penetrans ◽  
Meloidogyne Spp ◽  
Acacia Holosericea ◽  
Spore Attachment ◽  
High Degree ◽  
Root And Shoot Biomass

AbstractPasteuria penetrans isolates sampled from different geographical areas were characterised both for the heterogeneity of the endospore surface using monoclonal antibodies and for the ability of spores to attach to different isolates of Meloidogyne spp. The efficacy of these different Pasteuria isolates as biological control agents was tested in a glasshouse experiment with M. incognita from Senegal on Acacia holosericea. The immunoprofiles divided the P. penetrans isolates broadly differently from the attachment tests. Isolate PP16 from Senegal was associated with better seedling development of M. incognita-inoculated A. holoceria than were other isolates. Substantial variation in root and shoot biomass was not related to the observed variation in spore attachment tests. The difficulties involved in obtaining consistent biological control with Pasteuria are discussed in relation to the high degree of variability of this bacterium. Diversité chez l'hyperparasite bactérien Pasteuria penetrans en relation avec le contrôle du nématode Meloidogyne spp. sur Acacia holosericea - Des isolats de Pasteuria penetrans provenant de différentes régions géographiques ont été caractérisés en ce qui concerne, d'une part l'hétérogénéité de la surface des endospores - par utilisation d'anticorps monoclonaux -, d'autre part la capacité des spores à s'attacher à différentes souches de Meloidogyne spp. L'efficacité de ces différents isolats de P.penetrans en tant qu'agent de contrôle a été testée lors d'une expérience en serre utilisant un M. incognita d'origine sénégalaise et Acacia holosericea. Les isolats de P.penetrans ont montré des différences dans les profils immunologiques, différences non corrélées avec celles observées lors des tests d'attachement. En comparaison avec d'autres isolats, l'isolat PP16 provenant du Sénégal était associé à une meilleure croissance des plants de A. holosericea infestés par M. incognita. La variabilité importante touchant les biomasses aérienne et souterraine ne montrait aucune relation avec les différences observées lors des tests d'attachement. Les difficultés rencontrées pour obtenir un contrôle valable à l'aide de P.penetrans sont discutées en tenant compte du degré important de variabilité chez cette bactérie.

scholarly journals Selection of Microorganisms for Biological Control of Silver Scurf (Helminthosporium solani) of Potato Tubers

Plant Disease ◽  
1997 ◽  
Vol 81 (6) ◽  
pp. 647-652 ◽  
Author(s):  
M. K. Elson ◽  
D. A. Schisler ◽  
R. J. Bothast
Keyword(s):  
Biological Control ◽  
Xanthomonas Campestris ◽  
Physiological Age ◽  
Postharvest Disease ◽  
Silver Scurf ◽  
Infested Soil ◽  
Helminthosporium Solani ◽  
Biological Control Agents ◽  
Γ Irradiation ◽  
Selection Of

Few management strategies exist for silver scurf, an important postharvest disease of potatoes. In this study, the microbiota of 47 agricultural soils and 7 tuber samples was screened for biological control agents of silver scurf. Soil or periderm samples were transferred to separate samples of γ irradiation-sterilized field soil enriched with potato periderm. After incubation, the samples were assayed for biological suppressiveness to silver scurf using a whole-tuber/infested soil assay. Over 430 isolates of bacteria, yeasts, and actinomycetes were recovered from tubers and soil associated with the 12 most suppressive soil samples. Thirteen strains were selected for further study on three different strains of Helminthosporium solani, including one that was resistant to thiabendazole. Microbial strains that significantly inhibited H. solani (P ≤ 0.05) in at least one experiment were identified as Pseudomonas putida (PM1), Nocardia globerula (S244), and Xanthomonas campestris (P76). Colonization studies with rifampicin-resistant strains of putative biological control agents revealed that long-term colonization of the tuber surface was not necessary to reduce disease symptoms. Highly variable levels of conidiophore production prevented selection of the single most suppressive strain. Possible sources of variability in biological control are discussed, including physiological age of the tuber, tuber infection in the field, and uneven free moisture in the storage.

Interactions between Two Biological Control Agents and an Herbicide for Canada Thistle (Cirsium arvense) Suppression

2011 ◽  
Vol 4 (1) ◽  
pp. 151-158 ◽  
Author(s):  
Joanna K. Sciegienka ◽  
Elai N. Keren ◽  
Fabian D. Menalled
Keyword(s):  
Biological Control ◽  
Pseudomonas Syringae ◽  
Control Method ◽  
Management Program ◽  
Cirsium Arvense ◽  
Shoot Biomass ◽  
Control Methods ◽  
Biological Control Agents ◽  
Canada Thistle ◽  
Shoot Number

AbstractWe investigated the single and combined effects of two biological control agents, the stem-mining weevilHadroplontus lituraand the pathogenPseudomonas syringaepv.tagetis, with a herbicide (reduced or full application of glyphosate: 0.63 kg ae ha−1, or 3.78 kg ae ha−1, respectively) on the growth of Canada thistle,Cirsium arvense. We hypothesized that first, although each control method would have a negative effect on Canada thistle shoot biomass, root biomass, and shoot number, the integration of more than one control method would have greater impact than individual control methods. Second, we hypothesized that the order in which control methods are applied affects the outcome of the management program, with a pathogen application following weevil infestation being more effective than one prior to it. Although control methods impacted Canada thistle growth (P < 0.001, expect for a nonsignificant impact of glyphosate on shoot number), the combined effect of the three control methods behaved, generally, in an additive manner. A marginal interaction between the pathogen and the herbicide (P = 0.052) indicated a slight antagonistic interaction between these control methods. An interaction between the two biological control agents tested (P < 0.001) indicated that application of a pathogen prior to the release of weevil larvae could be more deleterious to Canada thistle than a late application. The observed, mostly additive, relationship between biological control agents and herbicides implies that integrating control methods rather than using a single approach could lead to greater Canada thistle control.

Yellow Brazilian Pepper-tree Leaf Galler (suggested common name) Calophya latiforceps Burckhardt (Insecta: Hemiptera: Calophyidae: Calophyinae)

EDIS ◽  
2017 ◽  
Vol 2017 (6) ◽  
Author(s):  
James P. Cuda ◽  
Patricia Prade ◽  
Carey R. Minteer-Killian
Keyword(s):  
Biological Control ◽  
North America ◽  
Natural Enemies ◽  
Host Plants ◽  
Classical Biological Control ◽  
Biological Control Agents ◽  
Pepper Tree ◽  
Brazilian Pepper ◽  
Close Relatives ◽  
Tree Leaf

In the late 1970s, Brazilian peppertree, Schinus terebinthifolia Raddi (Sapindales: Anacardiaceae), was targeted for classical biological control in Florida because its invasive properties (see Host Plants) are consistent with escape from natural enemies (Williams 1954), and there are no native Schinus spp. in North America. The lack of native close relatives should minimize the risk of damage to non-target plants from introduced biological control agents (Pemberton 2000). [...]

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