Fungal Infestation Research Articles

Test assemblies for monitoring decay in wood exposed above ground

No method exists for quantitatively evaluating the durability of wood exposed above ground. The aim of this study was to develop a test assembly that would (1) be conducive to rapid decay, (2) exhibit minimal variation between replicates in decay response, and (3) lend itself to nondestructive testing in the field. Eighteen different designs for test units of southern pine sapwood were tested in an open field in southern Mississippi in the United States and in a rainforest in Panama. At both locations, test units were exposed above ground to natural infestations of wood decay fungi. No design seemed particularly advantageous in the tropical climate. In the temperature climate, onset of wood decay and frequency of failed units at given intervals of exposure were influenced by the size of the units. Two designs met experimental objectives. Test units of these designs consisted of short lengths of 5·1 cm thick lumber, exposed horizontally, or of stacks of smaller beams that were supported at a 45° angle from the horizontal. These designs are being used in additional studies to assess the potential for using nondestructive stress-wave technology to quantitatively measure decay in the field.

Cutaneous Manifestations of Human Immunodeficiency Virus Infection

The prevalence of dermatologic problems during the course of human immunodeficiency virus infection makes knowledge of these skin manifestations imperative to all practicing dermatologists. Detection of early infection is encouraged as effective therapy now exists both to delay the progression of human immunodeficiency virus-induced immunodeficiency and to prevent opportunistic infections. Skin manifestations of human immunodeficiency virus infection discussed in this article include the following groups: neoplastic, ie, Kaposi's sarcoma, lymphoma, and squamous cell carcinoma; infectious, ie, viral, bacterial, fungal, protozoal, and arthropod infestations; and a miscellaneous group including papulosquamous, papular, vascular, autoimmune, oral, and drug-related skin disorders.

Aero-biological significance of Keratinophilic fungi in Kanpur

Airborne fungal infestation and its significance in biology and disease spread is well documented. Kanpur is an industrialized and agricultural area supporting highly polluted environment. Aerobiology. of the area is hitherto unexplored, moreso, with special reference to airborne Keratinophilic fungi. Such fungal organisms are known to cause degradation of keratinous substrates. Present endeavour was undertaken to screen and survey Keratinophilic fungi from local air dust.Tricophyton simii andChrysosporium indicum, two keratinophilous forms, were observed repeatedly during various calendar months. Findings emphasize the importance of these fungi in spread and control of diseases of nails, hair, horns and hoofs of cattle or human beings.

Ent-14[ S],16β,17-trihydroxyatisan-3-one and further constituents from Euphorbia fidjiana

The heartwood of the Fijian species Euphorbia fidjiana has yielded the new compounds ent-14[ S],16β,17-trihydroxyatisan-3-one, 5-hydroxyethylmellein, and 6-hydroxy-5-methylmellein, and 24 other compounds identified as stigmasterol, β-sitosterol, stigmasterone, β-sitosterone, 3-hydroxystigmastan-6-one, butyrospermol, 24-methylenecycloartan-3β-ol, cycloart-24-en-3β-ol, 3β-hydroxycycloart-25-en-24-one, 24-methylenecycloartan-3-one, cycloart-24-en-3-one, lasiodiplodin, des- O-methyllasiodiplodin, 5-methylmellein, 5-methoxymellein, 5-hydroxy-methylmellein, scopoletin, xanthoxylin, 2,4,6-trimethoxyacetophenone, erythritol, d-mannitol, d-arabitol, β- d-glucose, and α- d-glucose. Lasiodiplodin, des- O-methyllasiodiplodin and the three substituted melleins may be products of fungal infestation of the wood.

Incidence of mycotoxins in maize grains in Bihar State, India

A regular survey of some maize-growing areas of Bihar state, India, for three consecutive years (September 1984 to September 1986) revealed heavy infestations of mycotoxin-producing fungi with different maize samples. Aflatoxin-producing fungi had the highest frequency of occurrence in all the cases and aflatoxins were the most common mycotoxins elaborated by these fungi. Maize samples of the Kharif crop had a greater incidence of aflatoxins (47%) than the samples of rabi crop (17%). Stored maize grains also had a high incidence of aflatoxins (43%). Most of the contaminated samples contained aflatoxins at levels above 20 micrograms/kg.

Fire and fungus in a mountain hemlock forest

Two mortality factors create large-scale pattern in forests of Tsuga mertensiana in subalpine central Oregon Cascade Mountains. Half of an 18 000 - ha study area has experienced stand-destroying fire during the last 500 years. These fires varied in size from 1 to 3200 ha. Individual Phellinus weirii infestations are smaller than most fires and collectively cover less total area, but they are more numerous and fine-grained in their dispersion. Postfire stands are colonized by Pinus contorta, which persists for 2 centuries before being replaced by mountain hemlock. In stands older than 200 years, Phellinus weirii becomes apparent as it spreads from centers and forms patches where it infects trees and alters the plant community. Fungal isolates were collected from 61 infestations; these were subjected to clonal analyses. Spatial dispersion of ramets and genets supports the inference that many infestations are sibling ramets of genets that have survived stand-destroying fire. The age distribution of genets yields the inference that infestations have been initiated or modified by basidiospore infection during the past 1300 years. Several genets are older than 1000 years. Fire has reduced the visible area of infestation of the fungus. It probably has done so by favoring less susceptible host species and by reducing the modal size of dead roots and logs. While repeated fire could reduce the level of fungal infestation, infestations may enhance the probability of stand-destroying fires.

EFFECT OF SOME PRESERVATIVES AND FUNGICIDES IN ARRESTING FUNGAL INFESTATION OVER MARKETED BETEL NUT (ARECA CATECHU L.)

ABSTRACTBetel nut, a common masticatory, extensively chewed in India and other countries, is usually infested by a number of fungi. Many of them produce toxins. Attempts were made to control the fungal infestation of betel nuts by temperature treatment, and the use of preservatives and fungicides. Varying degrees of control of fungal infestation were seen. A temperature treatment of 60°C for 6 h totally inhibited fungi. Boric and propionic acids at 5% and 1%, respectively, were effective in completely suppressing the fungal growth on nuts in 4 weeks. Except for potassium metabisulphite, which inhibited fungal populations up to 80%, other salts at .5% to 1% inhibited fungal infestation 50 to 70%. Among the fungicides, Dithane M‐45 was quite effective at 0.2%, and was totally inhibitory at 5% in four weeks.

Heat Treatment for Control of Postharvest Diseases and Insect Pests of Fruits

Abstract Heat treatments have been used to control fungal diseases and insect infestation of fruit for many years. However, with the development of effective fungicides and insecticides, especially fumigants, which could be applied cheaply and easily, interest in heat treatments waned. Stringent short- and long-term safety studies imposed by the U.S. Environmental Protection Agency has made retention of registration for many agricultural chemicals increasingly difficult. Some of the fumigants, such as ethylene dibromide, which were developed and used to control insects during the past 20 to 30 years, are no longer registered; others may lose registration in the future. These regulatory restrictions also increase the cost of developing new chemical fumigants and, therefore, interest in heat disinfestation has been revived (5).

Effect of Fire on the Availability of Hollows in Trees Used by the Common Brushtail Possum, Trichosurus Vulpecula Kerr, 1792, and the Ringtail Possum, Pseudocheirus Peregrinus Boddaerts, 1785.

Characteristics of trees used for shelter during the day by brushtail and ringtail possums were identified in a study in open forest dominated by Eucalyptus marginata and E. calophylla in the Perup Fauna Nature Reserve, SW Western Australia. The effect of high-intensity fire on the availability of trees used by the possums was studied by comparing a burnt area (36 ha) with an unburnt area (22 ha) one and 32 months after the fire. Suitable hollows were used by possums regardless of the species, condition, height or size of the tree. Hollows deeper than 1 m were used significantly more frequently than shallow ones. Hollows of suitable size appear to develop in E. marginata when trees reach a mean age of about 300 yr, and in E. calophylla when trees reached a mean age of about 200 yr. The average age of trees inhabited by possums could be as high as 500 yr for E. marginata and 400 yr for E. calophylla. About 3 trees/ha were used by possums for diurnal refuge; the distribution of these trees was random. Fire of high intensity (1000-1400 kW/m) destroyed 38% of the trees previously inhabited by possums; the damage to other inhabited trees was related to their condition and the intensity of fire. In the longer term, high-intensity fire increased the rate of formation of hollows by direct excavation or by providing new sites for fungal and termite infestation. Thirty-two months after the fire, the average age of trees containing suitable hollows was estimated to be about 100 yr less than before the fire because of the destruction of older trees and the formation of new hollows, or the deepening of existing ones, in younger trees.

Theory and practice of site-specific drug delivery

All drugs act on discrete pharmacological receptors; however, their clinical use relies on their pharmacodisposition and pharmacokinetics combining to give an appropriate pharmacological response, coupled with the ability of the body to detoxify itself of any drug that has generally distributed. Although to date it has usually been possible to achieve drugs having these properties, not only are the disease targets becoming more difficult to attain, but the probabilities for success using the various high throughput screening techniques often employed are becoming low. The advent of the control of gene expression has given rise to both a plethora of new molecules and an understanding of normal and pathological processes; this is leading to new approaches to both the design and the clinical use of drugs. For these new classes of drugs, and for many drugs of the conventional type, there is a firm rationale for their site-specific delivery using carrier technology — such that the innate biological pathway of the carrier guide the drug to its pharmacological receptor in a protective form. This present contribution examines the rationale for site-specific drug delivery in terms of disease and drug and carrier properties, and the biological constraints and opportunities for site-specific drug delivery are examined by considering carrier access, retention and ability to control the timing of drug availability at site(s) of action(s). Although site-specific drug delivery is still rather empirical in its practice, examples are drawn from the literature to show the mistakes and successes in the use of site-specific carriers. These include their employment in macrophage activation, some other forms of cancer chemotherapy, retroviral diseases (including AIDS/ARC), gene therapy, enzyme-storage diseases, inflammation, graft versus host rejection disease, and fungal infestations. In addition, the challenges presented for the successful pharmaceutical development and clinical use of both soluble macromolecular and particulate colloidal carrier systems are discussed.

The plant metabolite 6-methoxybenzoxazolinone interacts with follicle-stimulating hormone to enhance ovarian growth.

6-Methoxybenzoxazolinone (6-MBOA) is a novel plant metabolite that enhances reproductive status in vertebrate consumers while it inhibits insect, fungal, and bacterial infestation of the plant. Ovaries of prepubertal rats show a dose response to increasing amounts of 6-MBOA.administered in Silastic capsule implants. Ovaries increased in size in response to capsules with 0.5-3.0 cm exposed surface area of 6-MBOA, whereas larger capsules (6 cm 6-MBOA) had no effect. Removal of the pituitary in both prepubertal and mature rats eliminated the stimulatory influence of 6-MBOA. In hypophysectomized animals treated with diethylstibestrol implants, 6-MBOA did not affect ovarian weight and no animals ovulated. Administration of follicle-stimulating hormone (FSH) increased ovarian weight and stimulated production of ova, and FSH combined with 6-MBOA resulted in larger ovaries that released more ova. 6-MBOA also enhanced ovarian growth in intact prepubertal animals treated with pregnant mare's serum gonadotropin. These results show that 6-MBOA has the ability to interact with FSH to stimulate follicular development and increase ovulation. Non-steroidal plant compounds may have a significant impact on the reproductive patterns of wild animal populations.

Winter legume and tillage effects on cotton growth and soil ecology

Field studies were conducted at 2 locations in Alabama during 1984 and 1985 to identify cultural practices which would improve cotton ( Gossypium hirsutum L.) stands when plantned no-till into winter legumes. The soils were a Decatur silt loam (Rhodic Paleudult) and a Norfolk sandy loam (Typic Paleudult). The experimental design was a randomized complete block with 4 replications. Whole plots consisted of winter annual legumes ( Vicia villosa Roth or Trifolium incarnatum L.) and fallow areas. Split-plot treatments established at cotton planting included conventional and conservation tillage, and fungicide. Soil samples were collected at cotton planting for population determination of Collembola and Acari species, and for estimation of cotton-disease fungus ( Rhizoctonia solani) infestation. Collembola populations were greater in the Decatur than Norfolk soils, and higher in legume-mulched than fallow soils by 39 and 72% for the Decatur and Norfolk soil, respectively. Disease infestation in the Decatur soil was 10% higher in legume than fallow plots, and 18% higher in legume than fallow plots in the Norfolk soil. Cotton populations were 19% less in legume than fallow areas, and 25% less with conservation (no-till) than with standard tillage. Bedding improved cotton stands by 21% compared to conservation tillage. Seed-cotton yields from the Decatur soil were consistently high (3798 kg ha −1, and there was no yield response to treatments. Maximum seed-cotton yields at the Norfolk site were achieved with conservation tillage in the fallow area, and conventional tillage in the legume area (both receiving fungicide).

Occurrence and Abundance of Eccrinaceous Fungi (Trichomycetes) in Brachyuran Crabs from Tampa Bay, Florida

ABSTRACT Fourteen species of brachyuran crabs from Tampa Bay, Florida, were examined for the occurrence and abundance of commensal trichomycetous fungi. Such fungi were found in the hindguts of six of these species, and all fungi observed belonged to the order Eccrinales. Percentage of occurrence of fungi in the infested species ranged from 10% (in Uca pugilator) to 70% (in Uca rapax). The fungi were quantified by estimating the total length of hyphae present in an individual crab. Mean amounts of fungi in the infested species ranged from 0.06 mm of hyphae per crab (U. pugilator) to 36.09 mm of hyphae per crab (Aratus pisonii). Separate collections were made in order to examine occurrence and abundance of fungi in three populations of A. pisonii and four populations of U. pugilator. Percentage of occurrence of fungi in populations of A. pisonii was from 80-95% and mean abundance of fungi was from 76.18-178.0 mm of hyphae per crab. Percentage of occurrence in populations of U. pugilator was from 5-25% and mean abundance of fungi was from 0.12-4.66 mm of hyphae per crab. The patterns of occurrence and abundance of fungi seemed best explained by the feeding habits of a species of crab, those with fungi being herbivorous and/or detritivorous. The present study has been the first to examine this type of fungal infestation from a quantitative perspective.

OCCURRENCE AND ABUNDANCE OF ECCRINACEOUS FUNGI (TRICHOMYCETES) IN BRACHYURAN CRABS FROM TAMPA BAY, FLORIDA

Fourteen species of brachyuran crabs from Tampa Bay, Florida, were examined for the occurrence and abundance of commensal trichomycetous fungi. Such fungi were found in the hindguts of six of these species, and all fungi observed belonged to the order Eccrinales. Percentage of occurrence of fungi in the infested species ranged from 10% (in Uca pugilator) to 70% (in Uca rapax). The fungi were quantified by estimating the total length of hyphae present in an individual crab. Mean amounts of fungi in the infested species ranged from 0.06 mm of hyphae per crab (U. pugilator) to 36.09 mm of hyphae per crab (Aratus pisonii). Separate collections were made in order to examine occurrence and abundance of fungi in three populations of A. pisonii and four populations of U. pugilator. Percentage of occurrence of fungi in populations of A. pisonii was from 80-95% and mean abundance of fungi was from 76.18-178.0 mm of hyphae per crab. Percentage of occurrence in populations of U. pugilator was from 5-25% and mean abundance of fungi was from 0.12-4.66 mm of hyphae per crab. The patterns of occurrence and abundance of fungi seemed best explained by the feeding habits of a species of crab, those with fungi being herbivorous and/or detritivorous. The present study has been the first to examine this type of fungal infestation from a quantitative perspective.

Influence of Ralgro® on suckling calf performance on tall fescue pastures with various levels of endophyte infestation (1988)

Four hundred and ten cow-calf pairs were allotted to tall fescue pastures containing 40, 45, or 70% endophyte fungus infestation. One half of the calves in each pasture were implanted with Ralgro® initially and reimplanted about 110 days later. Calf gains on the 70% endophyte fungus pasture showed a greater (P<.05) response to implanting than those grazing the 40 and 45% endophyte-infested tall fescue pastures during the 165 day trial.

Pecan quality after harvesting and moulding of different varieties store at high relative humidity

SummaryPecan nuts stored in their husks may be subjected to rapid mould deterioration. A study was designed to determine quality characteristics of pecan stored for 7 days before shelling. In addition, the moisture absorption of dry pecans and the increase in mould population of three varieties (Delmas, Moneymaker and Choctaw) stored under controlled conditions of 26 ± 1°C and 85% RH were investigated.When pecan nuts with husks were stored for 7 days in metal bins soon after harvesting, temperatures inside the bulk rose from 24 to 33°C. However, no notable increase in free fatty acids or in peroxide value of the nutmeals was recorded.The moisture content of pecan meat influenced fungal infestation: e.g. the moisture content of variety Moneymaker increased rapidly during storage and the final fungal count on this variety was relatively higher than other varieties. The increase in both parameters in Delmas was slower and a smaller fungal population was recorded at the end of the trial.

Vesicular‐Arbuscular Mycorrhizal Fungus Infestation and Phosphorus Fertigation to Overcome Pepper Stunting after Methyl Bromide Fumigation1

AbstractFumigation with methyl bromide (MB) is practiced to control pepper (Capsicum annuum L.) collapse disease, but in P‐sorbing soils the plants grow poorly after fumigation. A field trial was conducted on a high P‐sorbing soil (fossiliferous Typic Torriorthents) to compare P‐fertigation effects on plants grown on fumigated soil subsequently inoculated with Glomus macrocarpum Tul. &amp; Tul. [MB plus vesicular‐arbuscular mycorrhizal fungus (MB+VAMF)] and not inoculated (MB), and on nonfumigated soil (NF). Pepper plants in MB+VAMF were most mycorrhizal, and MB plants the least. Both VAMF inoculation and P fertigation controlled early season stunting. Plants fertigated with 1.3 mmol P L−1 weighed the most 9 weeks after seeding, and among them the MB+VAMF plants were the heaviest. After 9 weeks, all plots were fertigated with 0.6 mmol P L−1. Yields were high (61 to 65 Mg ha−1) where 0.4 mmol P L−1 and more was supplied early in the season, and highest (73 to 74 Mg ha−1) where both P fertigation and VAMF inoculation were used. The presence of significant quantities of mycorrhiza early in the growth season induced the highest percentage of large‐size fruit, thus making P fertilization with VAMF inoculation most beneficial. Phosphorus fertilization recommendations may have to be adjusted when used in conjunction with soil treatments that significantly reduce VAMF populations in the soil. High sorption made it impossible to raise the P concentration in the soil solution to a level that would support maximum nonmycorrhizal‐pepper growth, unless large quantities of P were supplied frequently in the irrigation water.

Fungal infestation of seeds from seven populations of wild oats (Avena fatuaL.) with different dormancy and viability characteristics

SummarySeeds from seven genetically inbred pure lines of wild oats (Avena fatuaL.) with different levels of dormancy and viability were analysed for seed‐borne fungi. All lines had fungi on the seeds. The predominating fungi wereAlternaria alternataandCladosporium herbarum, of which the latter was non‐pathogenic and the former only weakly pathogenic on seedlings of wild oats.Drechslera avenacea, Cochliobulus sativusandFusariumspp., frequently isolated, were pathogenic onA. fatua.OnlyD. avenaceawas host specific toA. fatuaand cultivated oatsAvena sativa. Cochliobolus sativusandFusariumspp, were equal or more pathogenic on seedlings of wheat (Triticum aestivumL.), barley (Hordeum vulgareL.), oats and rye (Secale cerealeL.) than on seedlings ofA. fatua. Drechslera avenaceaoccurred on a significantly higher percentage of seeds fromA. fatualines, AN 51 and AN 474, than from the other lines. Other fungi isolated occurred randomly on allA. fatualines. There was no relationship between low viability of seeds and fungi carried on the seeds.

Underground bulk storage of shelled corn in Minnesota

Shelled corn with a mean moisture content of 15.7 ± 0.7% was placed in two types of underground and aboveground bins: one constructed of flexible polyolefin and the other, a modified, metal hog feeder. Temperatures in the bins were monitored over a nine-month period, and two layer-by-layer autopsies on the underground bins were conducted at six months and nine months. Aboveground bins experienced either total loss due to fungal problems or serious insect infestations, whereas the underground bins remained free of detectable live insects and exhibited fungal growth associated only with flaws in bin construction (that is, in sample ports designed for withdrawal of grain samples during storage).

Interactions between oak tannins and parasite community structure: Unexpected benefits of tannins to cynipid gall-wasps.

Plant species vary tremendously in the number of phytophagous species they support. May (1979) and Price (1980) proposed that some of this variation may be due to variation in biochemical defenses. We find that variation between oak species in leaf tannin levels is positively correlated with 1) variation in the numbers of species of leaf-galling cynipid wasps those trees host; and 2) the density of individual galls per oak leaf. We hypothesize that leaf and gall tannins serve a protective function for cynipids, decreasing the amount of cynipid larval mortality due to fungal infestation. This defensive function would explain the observed positive relationships between oak tannin levels and cynipid diversity as well as cynipid abundance.