John C. Sutton

University of Guelph | UOGuelph · School of Environmental Sciences

Fusariosis (Fusarium solani f.sp. piperis) is one of the most damaging diseases of black pepper crop in the Amazon zone and the application of organic materials to the soil may be an alternative to control this disease. Leaf residues of Piper aduncum were evaluated before and after the extraction of essential oil, as additives to the soil inoculate...

Density patterns of colony-forming units (CFU) of the biocontrol agent Gliocladium roseum were investigated in raspberry cv. Boyne and cv. Redwing after spore suspensions (107 conidia/mL) were applied 2 h before dusk in field plots. Estimated density of G. roseum on leaves of both cultivars was 2 x 103 to 5 x 103 CFU/cm2 at 1 h after inoculation. D...

The ability of Pseudomonas chlororaphis 63-28 to suppress Pythium root rot (Pythium aphanidermatum) and promote plant growth was investigated in hydroponic peppers that were predisposed or not predisposed to the disease. The biocontrol agent was introduced into the nutrient solution 10 days before the roots were inoculated with the pathogen. The ro...

The type and concentration of phenolics found in the cytosol (free), cell wall (bound), and nutrient solution of hydroponic pepper (Capsicum annuum L.) inoculated with Pythium aphanidermatum (Edson) Fitzp. were compared with non-inoculated controls. The quantities and types of free phenolics found in the roots and nutrient solution were greater in...

Postinoculation wetness duration, temperature, and light conditions were investigated in relation.to infection of container-grown seedlings of black spruce (Piceamariana (Mill.) B.S.P) by Botrytiscinerea Pers.:Fr. Seedlings were predisposed to the pathogen by treatment at 35 ± 1 °C in darkness for 4 days immediately before inoculation, and infectio...

Effects of paclobutrazol on the ability of high temperature and drought to predispose black spruce (Piceamariana (Mill.) B.S.R) seedlings to infection and sporulation of Botrytiscinerea Pers.:Fr. were examined. Paclobutrazol was applied as a soil drench at doses of 0, 20, and 40 mg/seedling pair on the first and third days of 2- and 4-week periods...

Microbial isolates from conifer foliage and strawberry were evaluated for biocontrol of Botrytiscinerea Pers.:Fr. in container-grown seedlings of black spruce (Piceamariana (Mill.) B.S.P.). In growth room assays, seedlings were environmentally predisposed to the pathogen and coinoculated with the isolates and B. cinerea. Sporulation incidence of th...

Mycelial fungi associated with leaves, flowers, and fruits of strawberry (Fragaria × ananassa Duchesne) were monitored in a field plot from August 1986 to July 1987. The principal fungi found on leaves of various developmental stages were Alternaria alternata, Botrytis cinerea, Cladosporium spp., Colletotrichum dematium, Coniella fragariae, Epicocc...

Gray mold caused by Botrytis cinerea Pers.:Fr. developed in seedlings of black spruce (Picea mariana BSP) that were subjected to high temperatures (30–45 °C) in darkness or to drought conditions immediately before inoculation with the pathogen (106 conidia/mL). Incidence and density of spore production of B. cinerea in needles of the treated seedli...

The mycorrhizal fungus Glomus in association with bean hosts (Phaseolus vulgaris L.) was the dominant factor in the aggregation of sand particles in sterilized dune soil artificially inoculated either with Glomus, or with Glomus and a soil extract containing miscellaneous microorganisms. The weight of sand adhered to roots harvested from dried soil...

Seasonal and daily incidence of airborne spores of Bipolaris sorokiniana were studied in barley field plots in relation to crop development, disease severity, and weather variables. Sporulation was observed only on dead or senescent barley. The incidence of airborne spores before 8–11 July was low because spore-bearing barley foliage was scarce and...

Weather variables, leaf blight, and airborne spores of Botrytis squamosa were monitored in onion field plots at the Holland–Bradford Marsh, Ontario, in 1976. Incidence of spores showed marked daily periodicities with peaks normally between 0900 and 1200 hours Eastern Standard Time (EST). Daily spore counts were low (< 85 spores) during 7 to 28 July...

Black rot lesion development in cabbage leaves was correlated with accumulation of plugging material in the xylem vessels as Xanthomonas campestris multiplied and spread. Plug formation preceded a partial disorganization of the xylem, and spillage of bacteria from the vessels. The movement of eosin and 32PO43− was blocked within the vessels, and pl...

The extracellular polysaccharide fraction of Xanthomonas campestris was precipitated with hexadecyltrimethylammonium bromide from aqueous extracts of cabbage leaves infected with the black rot pathogen, and further purified by repeated precipitation with ethanol. The polysaccharide fraction was shown to be similar to extracellular polysaccharide fr...

A flotation–adhesion technique is described for the rapid recovery of Endogone spores using small (5–10 g) soil samples. The method proved 94–98% efficient in the recovery of spores from Ontario soils. Spore counts averaged 20–92 per gram with exceptional individual counts reaching 132. Effects of soil type, soil depth, and "host" plant on spore po...

Vesicular-arbuscular mycorrhizae developed extensively in a wide range of crop plants grown in field plots and in controlled environment. At 25–28 days after sowing, generally few roots (0.6–19%) were colonized by the mycorrhizal fungus Endogone. The proportion of roots colonized subsequently increased rapidly to maximum levels ranging from 48 to 8...

Grasses and herbs in the sand dunes of the eastern shores of Lake Huron were heavily colonized by the endomycorrhizal fungus Endogone. The fungus produced an extensive external mycelium in the dune sand. Numerous sand grains were firmly bound to the external mycelium, which was of structural importance in sand aggregates and was implicated as an im...

Root rot caused by Pythium species is a major problem in hydroponically-grown crops. Symptoms of canopy stunting are noticed in plants colonized by the pathogen and many times they are not diagnosed by the grower. The aim of this work was to evaluate biological control and plant growth promotion by Pseudomonas chlororaphis 63-28 and Bacillus subtil...

Tomato plants produced in pots in a greenhouse were kept in low intensities of photosynthetically active radiation (400-700 nm at means of 384, 308, 135, and 14 μmol·m–2·s–1) during 16-h photoperiods for 0, 5, 10, or 15 days. Immediately after treatment, leaflets of the fourth and fifth leaves were detached and inoculated with Botrytis cinerea Pers...

Inoculum, host development, weather factors, and disease were monitored in 1986-87 and 1987-88 as components of tan spot epidemics in winter wheat, caused by Pyrenophora tritici-repentis. Development of pseudothecia on wheat stubble residues exhibited a seasonal pattern in which the ascocarps enlarged during August-October, asci formed during Decem...

Mycelial fungi, yeasts, and bacteria were isolated from strawberry plants and evaluated for biocontrol of Botrytis cinerea in strawberry. Comparative tests were done on leaf discs and detached petals in the laboratory and on attached leaves and flowers in the growth room, greenhouse, and field plots. In the various controlled environments, strawber...

Inoculum concentration, leaf age, leaf wetness duration, and temperature markedly, and often interactively, affected numbers of lesions produced by Diplocarpon earlianum on strawberry leaves. Incidence of lesions at sites on leaves inoculated with 10-JL droplets of inoculum increased linearly with concentration of the inoculum (0 to 1 × 104 conidia...

Development of onion (Allium cepa) leaf blight caused by Botrytis squamosa was observed in relation to crop growth and weather factors in a field plot. A linear, simple-interest phase of disease progress early in the epidemic was followed mostly by logarithmic disease increase. The pathogen sporulated on necrotic leaves, beginning 30 days alter cro...

Temporal and quantitative relationships of environmental water with various stages of the infection cycle of Peronospora destructor and of related downy mildew pathogens are reviewed. The states, forms, and energy levels of environmental water as they affect the pathogens when associated with the host or during aerial dispersal are considered and p...

Black spruce (Picea mariana) seedlings were treated with Gliocladium roseum (5 × 10 7 conidia/mL) or with water, kept in high relative humidity (RH) for 24 h, challenge-inoculated with Botrytis cinerea (5 × 10 5 conidia/mL) or with water, and returned to high RH for 24 h, entirely at 20-21°C. The seedlings were subsequently kept in a growth chamber...

Epidemics of wheat head blight and maize ear rot in Canada are reviewed in relation to weather and incidence of mycotoxins. The biology and importance of Fusarium graminearum as a pathogen of wheat and maize in various regions of the world are summarized. In a detailed epidemiological profile of F. graminearum in wheat and maize, emphasis is placed...

Des semis d'epinettes noires [Picea mariana] furent maintenus sous une faible intensite lumineuse pendant 0-42 jours, et inocules avec Botrytis cinerea (10 6 conidies/mL). L'incidence de l'infection fut determinee indirectement en estimant l'incidence de sporulation de l'agent pathogene sur des segments d'aiguilles de 6 mm de longueur. L'incidence...

Peronospora parasitica sporulated on intact cabbage seedlings when subjected at 13°C or 18°C to free water, or to atmospheric water potentials (^) of 0 or 30 ±10 bars. The pathogen failed to sporulate at these temperatures when the atmospheric^ was 60, 90, or 120bars. More sporangia were produced at 13°C(1466-2265 sporangia/45 mm2cotyledons) than a...

Epidemics of onion leaf blight, caused by Botrytis squamosa, and strawberry gray mold, caused by B. cinerea, are considered in terms of host development, inoculum, infection and colonization of the host, symptom development and disease progress. Implications and applications of the epidemiologic information in disease management are discussed with...

Morphological development and interactions of Glioclodium roseum and Botrytis cinerea on leaves, stems, and stemens of Taspberry were examined by light microscopy. Tissues were inoculated with conidial suspensions of the antagonist, the pathogen, or both, and kept in continuous high humidity at 21-23°C. In the absence of B. cinerea, G. roseum produ...

Control of Botrytis cinerea by Gliocladium roseum was investigated in detached raspberry shoots maintained in high humidity. Sporulation incidence of B. cinerea in leaf disks, stem segments, stamens, and pistils respectively from shoots inoculated with 103, 104. 105, and 106 conidia of the pathogen mL-1 increased from 13 to 100%, 7 to 100%, 38 to 1...

The prevalence, incidence, and severity of fungal infections of the lower stem, crown, and roots of winter wheat in 105-109 fields in 11 counties of southwestern Ontario during July of 1985 and 1986 were determined in relation to precipitation, temperature, crop history, tillage practices, and soil pH and fertility. Fusarium avenaceum and F. acumin...

Conidia of Fusarium oxysporum f. sp. cyclaminis and zoospores of Pythium aphanidermatum were suspended in water and hydroponic nutrient solutions and treated with various doses of UV radiation (253.7 nm) by means of a collimated-beam apparatus and a flow-through apparatus. Germination and colony-forming ability of spores from treated suspensions we...

Epidemics and biological control of Pythium root rot were investigated in greenhouse cucumbers grown in small-scale hydroponic systems with troughs and recirculating nutrient solution. The systems were inoculated with Pythium aphanidermatum only or with the pathogen plus an isolate of Pseudomonas fluorescens or Pseudomonas chlororaphis. In systems...

Episodes of high root-zone temperature (33ºC) were investigated in relation to susceptibility of sweet pepper to root rot caused by Pythium aphanidermatum. Pepper plants were grown in aerated nutrient solution in hydroponic units positioned in temperature-controlled water baths. Root zone temperature was 23ºC except during high temperature treatmen...

Greenhouse cage trials were conducted to assess the effectiveness of bumble bee pollinators for the co-vectoring of two fungi (Beauveria bassiana [Balsamo] Vuillemin [BotaniGard 22WP® formulation] and Clonostachys rosea Lnk: Fr. [Endofine®]), in greenhouse tomato and sweet pepper for control of insect pests (greenhouse whitefly, Trialeurodes vapora...

Root browning is a principal symptom of pythium root rot of pepper (Capsicum annuum) caused by Pythium aphanidermatum, but its biochemistry and physiological importance are poorly understood. Phenolic compounds were quantified over time in hydroponically grown pepper plants that were inoculated with zoospores of P. aphanidermatum or not inoculated...

Relationships of cultural and harvesting practices in strawberries to epidemics of grey mould, caused by Botrytis cinerea, were examined in field plots in 1983 - 84 and 1984 - 85. The strawberries were grown in matted rows or solid beds and harvested by hand or by machine. Foliage cut by the machine was removed by hand-raking. Potential sporulation...

Clonostachys rosea strain 88-710 was evaluated for ability to promote growth and productivity of miniature roses, geraniums, and cucumbers grown in the absence or near absence of pathogens. For comparison, Pseudomonas chlororaphis strain 63-28 also was evaluated in cucumbers. For treatment of roses, conidial suspensions (5 × 106 conidia·ml -1 water...

Microbial control agents are traditionally applied to crops for arthropod pest control using chemical spray technology. Over the last 10-15 years, pollinator bees have been investigated as vectors for microbial control agents (fungi, viruses and bacteria). This paper reviews the development of the Pollinator Biocontrol Vector Technology and how pol...

São discutidos os efeitos de materiais orgânicos - casca de caranguejo e resíduos de Piper aduncum no controle da fusariose da pimenteira-do-reino em mudas enviveiradas.

This book contains 45 chapters divided into four sections, i.e. classical biocontrol programmes, inundative (or augmentative) biocontrol programmes (using nematodes, bacteria, fungi and viruses), conservation biocontrol programmes and networking in biocontrol. It describes the personal experiences of scientists from the initial search for suitable...

The capacity of several strains of root-colonizing bacteria to suppressPythium aphanidermatum, Pythium dissotocum and root rot was investigated in chrysanthemums grown in single-plant hydroponic units containing an aerated nutrient solution. The strains were applied in the nutrient solution at a final density of 104 CFU ml−1 and 14 days later the r...

The etiology and epidemiology of Pythium root rot in hydroponically-grown crops are reviewed with emphasis on knowledge and concepts considered important for managing the disease in commercial greenhouses. Pythium root rot continually threatens the productivity of numerous kinds of crops in hydroponic systems around the world including cucumber, to...

Potential of crab shell for reducing incidence of fusariosis and promoting growth of black pepper transplants Crab shell of the mangrove crab (Ucides cordatus) was tested as a soil amendment to reduce fusariosis and promote growth of black pepper (Piper nigrum) transplants. Soil infested with Fusarium solani f. sp. piperis was amended or not amende...

Crab shell of the mangrove crab (Ucides cordatus) was tested as a soil amendment to reduce fusariosis and promote growth of black pepper (Piper nigrum) transplants. Soil infested with Fusarium solani f. sp. piperis was amended or not amended with ground crab shell (1,0% m/m) 15 days before pepper seedlings were transplanted into the soil. The crab...

Three strawberry cultivars, Kent, Jewel and Blomidon, were evaluated for their reaction to leaf scorch (Diplocarpon earlianum) disease. The three cultivars are considered to be susceptible, moderately resistant and resistant to leaf scorch, respectively. Plants were grown in the field in a runnerless culture system and inoculated with conidial susp...

ABSTRACT The first characterization of alterations in whole-plant photosynthetic rate and carbon assimilation of bell peppers associated with infection by Pythium aphanidermatum is described. Relationships of root disease caused by P. aphanidermatum to whole-plant net carbon exchange rate (NCER), total carbon accumulation, dark respiration rates, w...

The relationship between severity of leaf scorch epidemics, caused by Diplocarpon earlianum, and components of vegetative growth and fruit yield was examined in 'Kent' strawberry (Fragaria xananassa Duch.). Plants were treated in July with six densities of initial inoculum of the pathogen, and severity of leaf scorch was assessed at 2-week interval...

Copper is one of the essential micro-nutrient elements for plants, but when in excess, is toxic to plants and other living organisms. Electrolytically generated copper and cupric sulphate are increasingly used by the greenhouse industry to control diseases and algae in hydroponic systems. However, there is little information regarding appropriate s...

The ability of the microbial agent Pseudomonas (Ps.) chlororaphis Tx-1 to suppress Pythium aphanidermatum and Pythium dissotocum, and control root rot, was investigated as a function of time of agent application and pathogen inoculation in vegetative-stage sweet peppers grown in single-plant hydroponic units. The agent was applied to the nutrient s...

Whole plant and leaf level alterations accompanying Pythium infection were examined. Hydroponic lettuce (Lactuca sativa L.) inoculated with Pythium dissotocum displayed cultivar-specific changes in primary productivity associated with disease progression. 'Bella Green', a susceptible cultivar, showed inhibited whole plant photosynthesis (measured a...

The ability of Pseudomonas (Ps.) chlororaphis isolate Tx-1 to suppress Pythium aphanidermatum and control root rot was investigated in sweet peppers grown in small-scale hydroponic trough units with recirculating nutrient solution. The agent was introduced to the nutrient solution 3 days after the peppers were inoculated with P. aphanidermatum, or...

An isolate of Pythium aphanidermatum and five isolates of Pythium dissotocum were examined for ability to colonize and produce symptoms in root systems of sweet pepper grown in aerated nutrient solution in single-plant hydroponic units in a research greenhouse. Repetitions of the study were conducted in April 2000, February 2001, and May 2001. Root...

Description This unique, new volume provides sixteen peer-reviewed papers, which address global topics related to the delivery of crop protection agents to their intended target sites. These papers demonstrate how the industry is working together in a rational and integrated manner with a view to continuing the production of CPA’s that are safe to...

The ability of Clonostachys rosea to establish and persist in deleafed tomato stems and to suppress sporulation potential of Botrytis cinerea was investigated in plots of hydroponic tomatoes in commercial greenhouses. Leaves near lower fruit clusters were removed according to standard practice and deleafed portions of the stems were treated with C....

The effect of microclimate variables on development ofClonostachys rosea and biocontrol ofBotrytis cinerea was investigated on rose leaves and crop residues. C.rosea established and sporulated abundantly on inoculated leaflets incubated for 7–35 days at 10°, 20° and 30°C and then placed on paraquat—chloramphenical agar (PCA) for 15 days at 20°C. On...

The production of essential commodities (O2, H2 O, and edible biomass) and removal of CO2 by higher plants in bioregenerative life support systems would be seriously limited by the occurrence of disease epidemics. Among several treatment possibilities is ultraviolet (UV) radiation, which is one of the preferred sterilization techniques due to cost...

Development of Clonostachys rosea in rose leaves and petals and control of Botrytis cinerea by the agent were investigated. C. rosea germinated, established endophytic growth, and sporulated abundantly whether the tissues were mature, senescent or dead when inoculated. Germination incidence was moderate on mature and senescent leaves (47% and 35%)...

Infestations of aphids(Macrosiphum rosae L.) and of twospotted spider mites(Tetranychus urticae Koch) were examined in relation to growth and sporulation ofClonostachys rosea andBotrytis cinerea, and to suppression of the pathogen by the agent, in green rose leaves. Leaves were infested artificially with 10 aphids/leaflet for 3 h, or naturally with...

The objective was to identify and characterize the causal agent of foliar necrosis and leaf scorch of Eucalyptus spp. in Brazil. Nineteen putative isolates of Rhizoctonia obtained from Eucalyptus plants during clonal propagation were compared with isolates from other hosts and with tester strains of anastomosis groups of Rhizoctonia solani. Feature...

Gliocladium roseumis a successful antagonist of Botrytis cinerea and is considered to have the major potential for biocontrol of the pathogen in cropping systems. In order to elucidate the optimal moment of the day to apply the biological control agent, geranium plants were inoculated until run off with a suspension containing 10 e7 conidia of G. r...

The occurrence of disease epidemics in bioregenerative life support systems would seriously limit the production of essential life support requirements. The capacity of diseased plants in closed environment chambers to scrub CO 2 was studied with lettuce plants infected with a common greenhouse pathogen, Pythium.At harvest, infected lettuce showed...

Microbial isolates from living petals, petal residues and leaf residues of rose, and from laboratory collections, were evaluated for control ofBotrytis cinerea in rose. In leaf residues artificially infested withB. cinerea, isolates of the filamentous fungiGliocladium roseum, FR136 (unidentified) andTrichoderma inhamatum reduced sporulation of the...

The effectiveness of bees in vectoring inoculum of the biocontrol agentGliocladium roseumto raspberry flowers was investigated in shade-cloth-enclosed field plots of raspberry cv. Boyne and cv. Redwing. For bee-vectoring treatments, a colony box of bumblebees with about 50 workers, or a hive of honeybees with about 3000 workers, was placed in each...

Nine progeny populations, derived from a half-diallel and self-crosses of strawberry cultivars Vantage, Scotland, Governor Simcoe and Kent were evaluated for resistance to leaf scorch (Diplocarpon earlianum) as seedling runners and at the adult-plant stage. At both stages selfed Vantage and selfed Scotland were resistant; crosses between Vantage an...

Gliocladium roseum (5×106 conidia ml-1) and chlorothalonil (Bravo 500) were compared in two field tests for effectiveness in suppressing leaf blight caused byBotrytis squamosa in cooking onions. The biological control agent and fungicide were applied with sprayers and with specially designed fabric applicators that were mounted interchangeably on a...

Inoculum concentration and time of application of Gliocladium roseum Bainier were examined in relation to sporulation of Botrytis cinerea Pers.:Fr. in container-grown seedlings of black spruce (Picea mariana (Mill.) BSP) in greenhouses. Gliocladium roseum concentrations ranging from 10(2) to 10(8) conidia/mL water plus surfactant, applied four rime...

Conidial concentration and age of host organs were investigated in relation to infection of geranium flowers and leaves by Botrytis cinerea. Infection was assessed indirectly by estimating sporulation incidence of the pathogen in inoculated tissues. Threshold concentrations of conidia for inferred infection were ≤10 spores per ml for petals, 10 to...

Eight isolates of Diplocarpon earlianum were evaluated for virulence, measured as the ability to produce percent leaf area with symptoms (LAS), on 18 cultivars of strawberry (Fragaria × ananassa). Significant differences were observed from isolate and cultivar effects, and isolate × cultivar interaction. Four of the eight isolates, on the average o...

This chapter focuses on microbial biocontrol of Botrytis cinerea in strawberry, in which the pathogen causes gray mold fruit rot, a destructive disease of worldwide importance. Consideration is given to background perspectives, concepts, methods, strategies, pitfalls, progress and future directions in this biocontrol system. Screening of strawberry...

In biocontrol tests, strawberry leaves were inoculated with Botrytis cinerea, were treated 2-5 wk later with antagonistic fungi or with chlorothalonil, and were kept on paraquat-chloramphenicol agar (PCA) or were sprayed with paraquat to kill the tissues and allow the pathogen to sporulate. Gliocladium roseum, a Penicillium sp., and Trichoderma vir...

A 3-yr field experiment was conducted on a Burford loam soil to examine how tillage practices and crop sequences affected the winter wheat (Triticum aestivum L.) crop in Ontario. Three-year crop sequences of wheat-wheat-wheat, soybeans (Glycine max Merrill)-wheat-wheat, corn (Zea mays L.)-barley (Hordeum vulgare L.)-wheat, corn-soybean-wheat, and a...

Pieces of maize and wheat stems colonized by Gibberella zeae were treated with acetic acid, propionic acid or urea and assessed for ability to produce perithecia or macroconidia after incubation. At 5% concentration, acetic and propionic acids reduced perithecial production by 85–100% on maize and wheat, while urea achieved a 97% reduction on maize...

Effects of crop sequences and tillage practices on diseases of winter wheat were examined. Three-year sequences ol continuous wheat, soybean-wheat-wheat, corn-barley-wheat, and alfalfa-alfalfa-wheat were produced under conventional, minimum, and zero tillage. The rotations followed mixed barley and oats Crop sequence and tillage treatment affected...

The requirements of field studies in plant disease epidemiology and weather-timed disease management on the farm have provided a strong impetus for developments in electronic monitoring of the crop microclimate. Recent innovations in electronic sensors have substantially improved the scope and practicality of measuring microclimatic variables while...

A forecaster of onion downy mildew, referred to as DOWNCAST, was evaluated under field conditions to determine its validity and effectiveness for timing fungicide sprays. DOWNCAST utilized criteria for predicting sporulation and infection by the downy mildew pathogen, Peronospora destructor. The criteria were based on quantitative and temporal rela...

Dead leaves, stolons, crowns and mummified berries of strawberries, dead weeds, straw and othe r plant residues in strawberry fields and plots were collected in fall and spring and incubated in humidity chamber s. Potential inoculum of B. cinerea on the residues was estimated f rom conidiop ho re counts. Ninety to 99% of the inoculum (conidia) was...

A spray-timing system for use in managing onion leaf blight, caused by Botrytis squamosa Walker, was developed using quantitative relationships of weather and the infection cycle of the pathogen. Daily microclimatic measurements were used to predict daily inoculum incidence and infection intensity, from which disease severity indices were computed....