Competition Between Fusarium pseudograminearum and Cochliobolus sativus Observed in Field and Greenhouse Studies

Among root pathogens, one of the most documented antagonisms is the suppression of Cochliobolus sativus by Fusarium (roseum) species. Unfortunately, previous studies involved single isolates of each pathogen and thus, provided no indication of the spectrum of responses that occur across the respective species. To investigate the variability in interactions between Cochliobolus sativus and Fusarium pseudograminearum, field and greenhouse trials were conducted that included monitoring of spring wheat plant health and monitoring of pathogen populations via quantitative real-time polymerase chain reaction. The interactions between two isolates of C. sativus and four isolates of F. pseudograminearum were explored in three geographically distinct wheat fields. To complement field trials and to limit potentially confounding environmental variables that are often associated with field studies, greenhouse trials were performed that investigated the interactions among and between three isolates of C. sativus and four isolates of F. pseudograminearum. Across field locations, C. sativus isolate Cs2344 consistently and significantly reduced Fusarium populations by an average of 20.1%. Similarly, F. pseudograminearum isolate Fp2228 consistently and significantly reduced C. sativus field populations by an average of 30.9%. No interaction was detected in the field between pathogen species with regards to disease or crop losses. Greenhouse results confirmed a powerful (>99%), broadly effective suppression of Fusarium populations by isolate Cs2344. Among greenhouse trials, additional isolate–isolate interactions were observed affecting Fusarium populations. Due to lower C. sativus population sizes in greenhouse trials, significant Fusarium suppression of C. sativus was only detected in one isolate–isolate interaction. This study is the first to demonstrate suppression of Fusarium spp. by C. sativus in field and greenhouse settings. These findings also reveal a complex competitive interaction between these two pathogen species that was previously unknown.

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Population Dynamics Between Fusarium pseudograminearum and Bipolaris sorokiniana in Wheat Stems Using Real-Time qPCR

Plant Disease ◽

10.1094/pdis-11-10-0794 ◽

2011 ◽

Vol 95 (9) ◽

pp. 1089-1098 ◽

Cited By ~ 7

Author(s):

Ernesto A. Moya-Elizondo ◽

Barry J. Jacobsen ◽

Andrew C. Hogg ◽

Alan T. Dyer

Keyword(s):

Population Dynamics ◽

Grain Yield ◽

Real Time ◽

Quantitative Polymerase Chain Reaction ◽

Bipolaris Sorokiniana ◽

Field Trials ◽

Crown Rot ◽

Fusarium Pseudograminearum ◽

Wheat Development ◽

Pathogen Populations

Fusarium pseudograminearum and Bipolaris sorokiniana are causal agents of Fusarium crown rot and common root rot, respectively, of wheat and cause significant losses worldwide. Understanding the population dynamics between these two pathogens at late stages of wheat development is needed. The effect of F. pseudograminearum and B. sorokiniana inocula applied singly or in mixtures at seeding to spring wheat ‘Hank’ was measured using seedling stand, grain yield, and pathogen populations in the first internode at heading, milk, and harvest stage of wheat development using real-time quantitative polymerase chain reaction. High and low rates of F. pseudograminearum inoculum reduced B. sorokiniana populations in field trials but B. sorokiniana inoculations did not affect F. pseudograminearum populations. Populations of both pathogens increased from heading until harvest, with F. pseudograminearum colonizing lower internodes earlier than B. sorokiniana. Neither pathogen prevented infection by the other in the first internode of wheat stems. Inoculations increased incidence of infection and co-infection relative to natural settings observed for both pathogens. At the seedling stage, both fungi, individually or combined, reduced the seedling stands when compared with a noninoculated control for the three location–years. Grain yield and F. pseudograminearum populations were inversely correlated, while B. sorokiniana populations were not correlated with yield.

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Influence of legume cover crops and conservation tillage on soil populations of selected fungal genera

Canadian Journal of Microbiology ◽

10.1139/m88-038 ◽

1988 ◽

Vol 34 (3) ◽

pp. 201-206 ◽

Cited By ~ 9

Author(s):

C. S. Rothrock ◽

W. L. Hargrove

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Conservation Tillage ◽

Field Studies ◽

Macrophomina Phaseolina ◽

Hairy Vetch ◽

Fusarium Spp ◽

Crimson Clover ◽

Legume Cover Crops ◽

Legume Cover Crop

The influence of winter legume cover crops and of tillage on soil populations of fungal genera containing plant pathogenic species in the subsequent summer sorghum crop were examined in field studies. Legume cover crops significantly increased populations of Pythium spp. throughout the sorghum crop compared with a rye cover crop or no cover crop. This stimulation of the populations of Pythium spp. was not solely due to colonization of cover-crop residue, as populations were significantly greater at the time the legume cover crop was desiccated. Removal of aboveground residue generally decreased populations of Pythium spp. in soil. Incorporation of residue by tillage increased populations of Pythium spp. at some sampling dates. Legumes differed in the magnitude of stimulation, with hairy vetch stimulating Pythium spp. more than crimson clover. Cover crop treatments did not consistently influence soil populations of Fusarium spp., Rhizoctonia solani, Rhizoctonia-like binucleate fungi, or Macrophomina phaseolina. Macrophomina phaseolina populations were significantly greater under no tillage.

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Managing Bees for Delivering Biological Control Agents and Improved Pollination in Berry and Fruit Cultivation

Sustainable Agriculture Research ◽

10.5539/sar.v4n3p89 ◽

2015 ◽

Vol 4 (3) ◽

pp. 89 ◽

Cited By ~ 8

Author(s):

Heikki M. T. Hokkanen ◽

Ingeborg Menzler-Hokkanen ◽

Marja-Leena Lahdenpera

Keyword(s):

Crop Protection ◽

Field Tests ◽

Weather Conditions ◽

Field Studies ◽

Field Trials ◽

Marketable Yield ◽

Dissemination Activity ◽

Grey Mold ◽

Commercial Farms ◽

Disease Pressure

Targeted precision biocontrol and improved pollination were studied Europe-wide in the EU ERA-NET CORE ORGANIC 2 project BICOPOLL (Biocontrol and Pollination). A case study was conducted on the management of strawberry grey mold Botrytis cinerea, with the biocontrol fungus, Gliocladium catenulatum, vectored by honey bees or bumble bees. A joint field trial carried out in five countries targeted strawberry cultivations in open field, and included four treatments: untreated control, chemical fungicide, entomovectored biocontrol, and chemical and biocontrol combined. In organic fields, no pesticide treatments were included. The proportion of moldy berries, and/or the marketable yield of healthy berries were recorded from each treatment, along with other parameters of local interest. A pilot study was started in Finland in 2006, and, by 2012, large commercial farms were using entomovectoring. In 2012, field trials were started in Estonia and in Italy, and in 2013-14, these experiments were expanded to Slovenia and Turkey. In total, 26 field tests were conducted using entomovectoring and Gliocladium catenulatum (Prestop® Mix) on strawberry, with five additional trials on raspberry. Efficacy results have been excellent throughout the field studies. The results show crop protection equalling or exceeding that provided by a full chemical fungicide program, under all weather conditions, and over a wide geographical range (from Finland to Turkey). Under heavy disease pressure, entomovectoring provided on average a 47% disease reduction, which was the same as multiple fungicide sprays. Under light disease pressure, biocontrol decreased grey mold by an average of 66%, which was greater than fungicide sprays. The concept has proven to be effective on strawberries, raspberries, pears, apples, blueberries, cherries, and grapes. A conservative estimate for Finland is that over 500 ha of strawberry cultivation currently use the technique (≈15% of the strawberry growing area). To make full use of the entomovectoring technique, organic berry and fruit growers are encouraged to (i) keep bees, or to hire the service from local beekeepers for entomovectoring; and (ii) manage vegetation within and around the target crop to support the activity of bees and other pollinators, which can help to disseminate the beneficial microbial populations within the crop. Beekeepers are encouraged to (i) market pollination and biocontrol services to fruit and berry growers, and (ii) ensure that all operations are effective in mananging bees and their microbe dissemination activity. Biocontrol product manufacturers are encouraged to further develop products and their formulations specifically for entomovectoring, because current formulations are suboptimal as they are initially optimized for other uses (e.g., mixing into the soil).

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Optimizing Sowing Depth of Tef for Irrigated Mediterranean Conditions: From Laboratory to Field Studies

Agronomy ◽

10.3390/agronomy10121983 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1983

Author(s):

Shiran Ben-Zeev ◽

Shane Kerzner ◽

Onn Rabinovitz ◽

Yehoshua Saranga

Keyword(s):

Field Experiments ◽

Field Studies ◽

Field Trials ◽

Eragrostis Tef ◽

Sowing Depth ◽

New Crops ◽

Different Depths ◽

Plant Emergence ◽

Increasing Demand ◽

Mediterranean Conditions

Developing new crops adapted to arid conditions is a promising approach to meet the increasing demand for food production under expanding aridity. Tef [Eragrostis tef (Zucc.) Trotter] is a C4 cereal crop cultivated mainly in Ethiopia and the Horn of Africa, and known for its high resilience to stressful environments. Due to their tiny size, tef seeds are traditionally sown by broadcasting and lightly covering with soil. Under semiarid Mediterranean conditions, a deeper sowing may guarantee seedling establishment while saving on irrigation water. The objective of this study was, therefore, to determine the effects of sowing depth on tef emergence, development, lodging, and productivity. Tef seeds were sown at different depths in test tubes and pots, and in two field experiments. In tubes and pots, time from sowing to emergence increased about twofold and emergence rate decreased in the deepest sowing (3 cm) treatment compared to controls (0 cm). In the pot and field trials, deep sowing (3 cm) significantly reduced plant height, shoot and root biomass, and lodging. Sowing depths of 1–2 cm allowed successful plant establishment while not exacting penalties on plant emergence or development; hence this range appears to be optimal for sowing irrigated tef.

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Reliability of Singing Bird Surveys: Changes in Observer Efficiency with Avian Density

The Auk ◽

10.1093/auk/101.2.307 ◽

1984 ◽

Vol 101 (2) ◽

pp. 307-318 ◽

Cited By ~ 51

Author(s):

Jonathan Bart ◽

James D. Schoultz

Keyword(s):

Measurement Error ◽

General Procedure ◽

Field Studies ◽

Abundant Species ◽

Common Species ◽

Field Trials ◽

Bird Songs ◽

Auditory Cues ◽

Basic Assumptions ◽

Maximum Estimate

Abstract Field trials in which paired observers were used and indoor simulations in which recorded bird songs were used indicated that, as the number of singing birds audible from a listening station increased from 1 to 4, the fraction of them recorded by observers declined by up to 50%. This reduction in efficiency violates one of the basic assumptions of any index-that the proportion of animals detected remains constant-and could cause surveyors who rely primarily on auditory cues to underestimate changes in population density by up to 25% for common species and 33% for abundant species. The change in efficiency, which is best regarded as measurement error, cannot be detected by a statistical examination of the data and thus may pass undetected in many field studies. It seems unlikely that any general procedure for "correcting" the error would be reliable. The results indicate that singing bird surveys of common species should be supplemented by other methods if accurate estimates of changes in density are needed. A general conclusion of the study is that whenever animals "compete" for a place in the survey, for example by filling up traps or suppressing one another's songs, then the index tends to underestimate a change in density. If efficiency increases with density, then the survey tends to overestimate a change in density. If the sign of the bias can be determined, the survey can be used to provide a minimum or maximum estimate of a change in density even if the magnitude of the bias cannot be estimated.

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Influence of soil pH, rainfall, dosage, and application timing of herbicide Merlin 750 WG (isoxaflutole) on phytotoxicity level in maize (Zea mays L.)

Plant Soil and Environment ◽

10.17221/3687-pse ◽

2011 ◽

Vol 50 (No. 2) ◽

pp. 88-94 ◽

Cited By ~ 5

Author(s):

J. Soukup ◽

M. Jursík ◽

P. Hamouz ◽

J. Holec ◽

J. Krupka

Keyword(s):

Soil Ph ◽

Weight Reduction ◽

Zea Mays L ◽

Field Studies ◽

Field Trials ◽

Early Growth ◽

Application Timing ◽

Pot Trials ◽

Phytotoxic Effect ◽

Shoot Weight

Pot trials and field studies were carried out to describe the influence of soil pH and rainfall on the phytotoxic effect of the herbicide Merlin 750 WG (isoxaflutole) in maize. Symptoms as bleaching, and root and shoot weight reduction in early growth of maize were found. In pot trials, a statistically significant crop injury in early growth of maize was found only at the herbicide dose of 100 and 130 g/ha followed by 30 mm precipitation directly after herbicide application in soils with pH 6.5 and 7.2. Bleaching and significant weight reduction of maize up to growth stage BBCH 13 were observed in field trials at treatments with early post-emergence application of Merlin and 20 mm precipitations. Bleaching symptoms recovered up to BBCH 19. Significant differences were found in maize shoot weight and cob yield between treatments with and without watering (20 mm irrigation), and between pre- and post-emergence application of Merlin under field conditions. No significant differences were found between herbicide doses tested.

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Application of the Droplet Digital Polymerase Chain Reaction (ddPCR) Platform for Detection and Quantification of Vertebrate Host DNA in Engorged Mosquitoes

Journal of Medical Entomology ◽

10.1093/jme/tjz016 ◽

2019 ◽

Vol 56 (4) ◽

pp. 1150-1153

Author(s):

L M Rice ◽

L L Robb ◽

D A Hartman ◽

J R Anderson ◽

R C Kading

Keyword(s):

Polymerase Chain Reaction ◽

New Technology ◽

Field Studies ◽

Blood Feeding ◽

Absolute Quantification ◽

Spatial And Temporal Patterns ◽

Chain Reaction ◽

Vector Borne Diseases ◽

Polymerase Chain ◽

Digital Polymerase Chain Reaction

Abstract Hematophagous arthropod bloodmeal identification has remained a challenge in the field of vector biology, but these studies are important to understand blood feeding patterns of arthropods, spatial, and temporal patterns in arbovirus transmission cycles, and risk of human and veterinary disease. We investigated the use of an existing vertebrate primer set for use on the droplet digital polymerase chain reaction (ddPCR) platform, to explore the use of this technology in the identification and quantification of vertebrate DNA in mosquito blood meals. Host DNA was detectable 48-h post-engorgement in some mosquitoes by ddPCR, compared with 24-h post-engorgement using traditional PCR. The capability of ddPCR for absolute quantification of template DNA offers unique potential applications of this new technology to field studies on the ecology of vector-borne diseases, but currently with limited scope.

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Response of Processing Peas(Pisum sativum)and Annual Weeds to Acetanilide Herbicides

Weed Science ◽

10.1017/s0043174500050013 ◽

1978 ◽

Vol 26 (4) ◽

pp. 313-317 ◽

Cited By ~ 10

Author(s):

G. L. Jordan ◽

R. G. Harvey

Keyword(s):

Pisum Sativum ◽

Relative Effectiveness ◽

Field Studies ◽

Field Trials ◽

Silica Sand ◽

Simulated Rainfall ◽

Annual Grass ◽

Excellent Control ◽

Glycine Ethyl Ester ◽

Annual Weeds

The relative effectiveness of eight acetanilide herbicides for controlling annual weeds in processing peas(Pisum sativumL.) was evaluated in field studies and the susceptibility of peas to injury from these herbicides was studied in both the field and greenhouse. Alachlor [2-chloro-2′,6′-diethyl-N-(methoxymethyl)acetanilide] was the most phytotoxic to peas grown in washed silica sand in the greenhouse when the herbicides were applied at concentrations of 2 and 8 mg/L. Field trials conducted over a 2-yr period and simulated rainfall experiments in the greenhouse demonstrated that the phytotoxicity to peas by acetanilide herbicides applied preemergence at 2.2 and 4.5 kg/ha was greatly influenced by subsequent rainfall. When 2.5 cm of simulated rainfall were applied immediately after herbicide application, pea injury increased. Injury to peas was avoided in the field by delaying alachlor application at 2.2 kg/ha until peas began to emerge. This treatment also gave excellent control of annual grass weeds. Greenhouse studies demonstrated that injury to peas by all eight acetanilide herbicides at 2.2 and 4.5 kg/ha could be avoided by delaying application until pea emergence. Alachlor, propachlor (2-chloro-N-isopropylacetanilide), and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] gave slightly superior weed control than butachlor [N-(butoxymethyl)diethylacetanilide] and H 22234 [N-chloroacetyl-N-(2,6-diethylphenyl)-glycine ethyl ester].

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Resistance of Pinus taeda families under artificial inoculations with diverse fusiform rust pathogen populations and comparison with field trials

Canadian Journal of Forest Research ◽

10.1139/x08-111 ◽

2008 ◽

Vol 38 (10) ◽

pp. 2687-2696 ◽

Cited By ~ 19

Author(s):

Fikret Isik ◽

Henry V. Amerson ◽

Ross W. Whetten ◽

Saul A. Garcia ◽

Bailian Li ◽

...

Keyword(s):

Pinus Taeda ◽

Total Variation ◽

Field Trials ◽

Fusiform Rust ◽

Artificial Inoculations ◽

Single Field ◽

Resistant Family ◽

Pinus Taeda L ◽

Pathogenic Variability ◽

Pathogen Populations

Controlled inoculations with 10 bulk inocula of Cronartium quercuum (Berk) Miyabe ex Shirai f.sp. fusiforme were carried out on open-pollinated progeny of 25 fast-growing Pinus taeda L. parents. The parents had a range of breeding values for resistance to fusiform rust in progeny field trials. There were highly significant differences among the half-sib families in response to inoculations, and these differences were very reproducible; the half-sib family-mean heritability of resistance to controlled inoculation was 0.97. All of the families that were susceptible in the field were susceptible in controlled inoculations, and most (12 of 17) of the field-resistant families were resistant in response to controlled inoculations. Significant pathogenic variability was observed among the different bulk inocula, although this accounted for only 1.9% of the total variation. Genetic differences among families within field-resistant or field-susceptible groups accounted for 13.7% of the total variation. The family by inocula interaction was highly significant, but a single field-resistant family contributed 44% of the total family by inocula interaction variance, and two other field-resistant families also showed significant interactions.

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Evidence for insect transmission of rabbit haemorrhagic disease virus

Epidemiology and Infection ◽

10.1017/s0950268802007756 ◽

2002 ◽

Vol 129 (3) ◽

pp. 655-663 ◽

Cited By ~ 29

Author(s):

K. A. McCOLL ◽

J. C. MERCHANT ◽

J. HARDY ◽

B. D. COOKE ◽

A. ROBINSON ◽

...

Keyword(s):

Laboratory Experiments ◽

Infectious Virus ◽

Fold Increase ◽

Field Trials ◽

Rabbit Haemorrhagic Disease Virus ◽

Chain Reaction ◽

Rabbit Haemorrhagic Disease ◽

Insect Populations ◽

Polymerase Chain ◽

Haemorrhagic Disease

The spread of rabbit haemorrhagic disease (RHD) virus from quarantine on Wardang Island to mainland Australia in 1995 suggested that insects could be potential vectors. Field observations and laboratory experiments were conducted to address aspects of this hypothesis. Firstly, the variation in insect populations on the island during the field trials was examined. There was approximately a 1000-fold increase in the number of bushflies, Musca vetustissima, shortly before the spread of the virus. Secondly, M. vetustissima were tested in the laboratory as potential vectors of RHD virus, and it was demonstrated that disease could be transmitted between rabbits by flies. Finally, 13 of 16 insect samples, collected from Wardang Island and from several sites on the mainland following the spread of virus off the island, were positive for the presence of RHD virus by a specific polymerase chain reaction (PCR). Only one sample contained sufficient infectious virus to kill a susceptible rabbit. These data, combined with previously published information on fly biology, suggested that flies, particularly bushflies, may be involved in the transmission of RHD virus. Other possible routes of spread were not assessed in this study.

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