The Xenon Test Chamber Q-SUN® for testing realistic tolerances of fungi exposed to simulated full spectrum solar radiation.

The low survival of insect-pathogenic fungi when used for insect control in agriculture is mainly due to the deleterious effects of ultraviolet radiation and heat from solar irradiation. In this study, conidia of 15 species of entomopathogenic fungi were exposed to simulated full-spectrum solar radiation emitted by a Xenon Test Chamber Q-SUN XE-3-HC 340S (Q-LAB® Corporation, Westlake, OH, USA), which very closely simulates full-spectrum solar radiation. A dendrogram obtained from cluster analyses, based on lethal time 50 % and 90 % calculated by Probit analyses, separated the fungi into three clusters: cluster 3 contains species with highest tolerance to simulated full-spectrum solar radiation, included Metarhizium acridum, Cladosporium herbarum, and Trichothecium roseum with LT50 > 200 min irradiation. Cluster 2 contains eight species with moderate UV tolerance: Aschersonia aleyrodis, Isaria fumosorosea, Mariannaea pruinosa, Metarhizium anisopliae, Metarhizium brunneum, Metarhizium robertsii, Simplicillium lanosoniveum, and Torrubiella homopterorum with LT50 between 120 and 150 min irradiation. The four species in cluster 1 had the lowest UV tolerance: Lecanicillium aphanocladii, Beauveria bassiana, Tolypocladium cylindrosporum, and Tolypocladium inflatum with LT50 < 120 min irradiation. The QSUN Xenon Test Chamber XE3 is often used by the pharmaceutical and automotive industry to test light stability and weathering, respectively, but it was never used to evaluate fungal tolerance to full-spectrum solar radiation before. We conclude that the equipment provided an excellent tool for testing realistic tolerances of fungi to full-spectrum solar radiation of microbial agents for insect biological control in agriculture.

Responses of entomopathogenic fungi to the mutagen 4-nitroquinoline 1-oxide.

Survival of entomopathogenic fungi under solar ultraviolet (UV) radiation is paramount to the success of biological control of insect pests and disease vectors. The mutagenic compound 4-nitroquinoline 1-oxide (4-NQO) is often used to mimic the biological effects of UV radiation on organisms. Therefore, we asked whether tolerance to 4-NQO could predict tolerance to UV radiation in thirty isolates of entomopathogenic fungi and one isolate of a xerophilic fungus. A dendrogram obtained from cluster analyses based on the 50 and 90 % inhibitory concentrations (IC50 and IC90, respectively) divided the fungal isolates into six clusters numbered consecutively based on their tolerance to 4-NQO. Cluster 6 contained species with highest tolerance to 4-NQO (IC50 > 4.7 µM), including Mariannaea pruinosa, Lecanicillium aphanocladii, and Torrubiella homopterorum. Cluster 1 contained species least tolerant to 4-NQO (IC50 < 0.2 µM), such as Metarhizium acridum (ARSEF 324), Tolypocladium geodes, and Metarhizium brunneum (ARSEF 7711). With few exceptions, the majority of Metarhizium species showed moderate to low tolerances (IC50 between 0.4 and 0.9 µM) and were placed in cluster 2. Cluster 3 included species with moderate tolerance (IC50 between 1.0 and 1.2 µM). In cluster 4 were species with moderate to high tolerance (IC50 between 1.3 and 1.6 µM). Cluster 5 contained the species with high tolerance (IC50 between 1.9 and 4.0 µM). The most UV tolerant isolate of M. acridum, ARSEF 324, was the least tolerant to 4-NQO. Also, L. aphanocladii, which is very susceptible to UV radiation, showed high tolerance to 4-NQO. Our results indicate that tolerance to 4-NQO does not correlate with tolerance to UV radiation. Therefore this chemical compound is not a predictor of UV tolerance in entomopathogenic fungi.

Gastrointestinal Basidiobolomycosis: An Emerging, and A Confusing, Disease in Children (A Multicenter Experience).

INTRODUCTION: Gastrointestinal basidiobolomycosis (GIB) is an emerging fungal infection in children that leads to diagnostic confusion. AIM: Our study aim was twofold: a systematic review of published literature and an update of some Saudi Arabia hospital series to analyze their as well as our own experience in diagnosis and management of GIB. MATERIAL AND METHODS: This clinical study included 18 children whose final diagnosis was GIB. The patients, who ranged in age from 5 to 10 years, were admitted between November 2009 and November 2015 with vague abdominal pains with or without abdominal masses for further investigation. RESULTS: Abdominal pain was the most common presenting symptom (94.4%) followed by constipation and abdominal mass (83.3 and 77.8%, respectively); fever was present in only 22.2% of the cases. Elevated inflammatory markers and eosinophilia (94.4%) appeared as prominent laboratory findings. CONCLUSION: We conclude that diagnosing GIB in children requires a high index of suspicion, awareness, and consideration of its possibility in the differential diagnosis in patients with abdominal masses and eosinophilia, particularly in areas where it is endemic. Increased awareness of this clinical entity, early surgical resection of the infected tissue, and prolonged treatment with itraconazole offer the best chance for curing the disease.

The effect of synthetic pesticides and sulfur used in conventional and organically grown strawberry and soybean on Neozygites floridana, a natural enemy of spider mites.

BACKGROUND: The beneficial fungus Neozygites floridana kills the two-spotted spider mite Tetranychus urticae, which is a serious polyphagous plant pest worldwide. Outbreaks of spider mites in strawberry and soybean have been associated with pesticide applications. Pesticides may affect N. floridana and consequently the natural control of T. urticae. N. floridana is a fungus difficult to grow in artificial media, and for this reason, very few studies have been conducted with this fungus, especially regarding the impact of pesticides. The aim of this study was to conduct a laboratory experiment to evaluate the effect of pesticides used in strawberry and soybean crops on N. floridana. RESULTS: Among the pesticides used in strawberry, the fungicides sulfur and cyprodinil + fludioxonil completely inhibited both the sporulation and conidial germination of N. floridana. The fungicide fluazinam affected N. floridana drastically. The application of the fungicide tebuconazole and the insecticides fenpropathrin and abamectin resulted in a less pronounced negative effect on N. floridana. Except for epoxiconazole and cyproconazole, all tested fungicides used in soybean resulted in a complete inhibition of N. floridana. Among the three insecticides used in soybean, lambda-cyhalothrin and deltamethrin resulted in a significant inhibition of N. floridana. CONCLUSION: The insecticides/ acaricides abamectin and lambda-cyhalothrin at half concentrations and fenpropathrin and permethrin and the fungicide tebuconazole at the recommended concentrations resulted in the lowest impact on N. floridana. The fungicides with the active ingredients sulfur, cyprodinil + fludioxonil, azoxystrobin, azoxystrobin + cyproconazole, trifloxystrobin + tebuconazole and pyraclostrobin + epoxiconazole negatively affected N. floridana. © 2015 Society of Chemical Industry.

A Case Report of Gastrointestinal Basidiobolomycosis Treated With Voriconazole: A Rare Emerging Entity.

INTRODUCTION: Basidiobolomycosis is an unusual fungal disease that rarely involves the visceral organs such as gastrointestinal tract. Gastrointestinal basidiobolomycosis (GIB) has been increasingly reported in the literature, and it is an emerging disease from arid regions worldwide, in particular, the south-western Saudi Arabia. We report a case of GIB in a 36-year-old Saudi Arabian male patient showing resistance to itraconazole and best treated with voriconazole. Computed tomography showed diffusely thickened small bowel with edematous change. CONCLUSIONS: As GIB presents diagnostic challenges due to lack of specific features, this case emphasizes the importance of considering GIB in the differential diagnosis in patients presenting with fever, abdominal pain with fast-growing abdominal mass.

Fungal inflammatory masses masquerading as colorectal cancer: a case report.

BACKGROUND: Non malignant invasive tumors of the colon and rectum are very rare. Gastrointestinal Basidiobolomycosis can present as a mass lesion mimicking colorectal cancer. CASE PRESENTATION: A 56 year old Caucasian male was evaluated for abdominal and pelvic pain for 4 weeks complicated by acute urinary retention. Radiological evaluation showed him to have recto-sigmoid and cecal mass. Endoscopic examination and biopsies did not reveal a definite diagnosis. Computerized tomography guided biopsy of the mass showed fungal elements consistent with gastrointestinal basidiobolomycosis. He was treated with Itraconazole for 12 months with very good clinical and radiological response. CONCLUSION: Basidiobolomycosis of the gastrointestinal tract should be considered during evaluation of colorectal masses with atypical presentation. It is a rare entity seen more in endemic regions of the world for basidiobolomycosis including southwestern United States.

Entomophthoromycosis: a challenging emerging disease.

Entomophthoromycosis is a rare fungal infection that may affect immunocompetent hosts; predominantly in tropical and subtropical regions. Recently, the importance of this emerging mycosis has increased and the scope of its manifestations has been expanded. These manifestations; however, may masquerade as other clinical entities. Prompt diagnosis of this infection requires a high index of suspicion. Although histopathological examination and cultures are the gold standard diagnostic tools; molecular diagnosis is now available and started to play an important role. The cornerstone treatment is prolonged anti-fungal therapy along with surgical debridement. More awareness of this mycosis is warranted for definitive diagnosis and implementation of early proper therapeutic strategies.

Successful treatment of gastrointestinal basidiobolomycosis with voriconazole without surgical intervention.

Basidiobolomycosis is a rare disease due to fungus Basidiobolus ranarum, an environmental saprophyte that is found worldwide, though mainly reported in the tropical and subtropical regions. Basidiobolomycosis is an unusual fungal skin infection, rarely involves the gastrointestinal (GI) tract. Most of the cases of paediatric GI basidiobolomycosis (GIB) were reported from the southern region of Saudi Arabia. We report an 11-year-old Saudi boy. He presented with a huge right lower quadrant abdominal mass and marked eosinophilia. Abdominal computed tomography scan revealed a large caecal mass. A biopsy was taken and it showed transmural granulomatous inflammation. A diagnosis of GIB was confirmed by specific features in histopathology. Most of the reported paediatric cases with GIB required adjuvant therapy of antifungal and surgical resection. In our case, treatment with voriconazole alone for 1 year was successful with complete recovery and with no recurrence after a year of discontinuing the treatment.

Colonic basidiobolomycosis in a child: report of a culture-proven case.

Basidiobolomycosis is a rare fungal disease caused by Basidiobolus ranarum, which is endemic in tropical and subtropical regions of Africa, Asia, and Latin America. Gastrointestinal basidiobolomycosis poses diagnostic difficulties due to the non-specific clinical presentation and absence of predisposing factors. Eight pediatric cases of the disease have been reported recently from Iran, but none of these, or most of the other cases reported in the literature, has been proven by culture, which is the gold standard method for diagnosis. We present a case of culture-proven colonic basidiobolomycosis that occurred in a 3-year-old boy. The outcome was successful following surgical excision and antifungal therapy with posaconazole.

Impacts of thiamethoxam seed treatment and host plant resistance on the soybean aphid fungal pathogen, Pandora neoaphidis.

Since the introduction of soybean aphid, Aphis glycines Matsumura, from Asia, insecticide use in soybean has increased substantially in the north central United States. Insecticide seed treatments and aphid resistant soybean varieties are management tactics that may reduce reliance on foliar applications of broad-spectrum insecticides. Exploring potential nontarget impacts of these technologies will be an important step in incorporating them into aphid management programs. We investigated impacts of thiamethoxam seed treatment and Rag1 aphid resistant soybean on a fungal pathogen of soybean aphid, Pandora neoaphidis (Remaudière & Hennebert) Humber, via open plot and cage studies. We found that although thiamethoxam seed treatment did significantly lower aphid pressure in open plots compared with an untreated control, this reduction in aphid density translated into nonsignificant decreases in fungal disease prevalence in aphids. Furthermore, when aphid densities were approximately equal in seed treated and untreated soybean, no impact on aphid fungal disease was observed. In open plots, Rag1 resistant soybean experienced lower aphid pressure and aphid disease prevalence compared with a nonresistant isoline. However, in cages when aphid densities were equivalent in both resistant and susceptible soybean, resistance had no impact on aphid disease prevalence. The addition of thiamethoxam seed treatment to resistant soybean yielded aphid densities and aphid disease prevalence similar to untreated, resistant soybean. These studies provide evidence that thiamethoxam seed treatments and Rag1 resistance can impact P. neoaphidis via decreased aphid densities; however, this impact is minimal, implying use of seed treatments and host plant resistance are compatible with P. neoaphidis.

Non-target impacts of soybean rust fungicides on the fungal entomopathogens of soybean aphid.

Soybean aphid, Aphis glycines, has caused serious economic damage to soybean across the North Central US since its introduction to North America in 2000. The management of another invasive soybean pest, Asian soybean rust, Phakopsora pachyrhizi, using foliar fungicide applications has the potential to impact soybean aphid populations by suppressing beneficial fungal entomopathogens. In 2005 and 2006, we applied recommended soybean rust fungicide treatments, consisting of strobilurin and triazole fungicides, to small soybean plots in two locations to assess if such applications might suppress aphid fungal epizootics. In Lamberton, MN, in 2005, during the epizootic, fungicide-treated plots averaged 2.0+/-0.7% (mean+/-SE) disease prevalence while untreated plots averaged 14.2+/-5.6%. In 2007, we applied strobilurin and strobilurin-triazole mix fungicides to single-plant microplots either before or after release of Pandora neoaphidis, the most commonly observed aphid pathogen in 2005 and 2006. Treatments that contained a mixture of two active ingredients significantly lowered peak and cumulative aphid disease prevalence in both early and late reproductive stage soybeans indicating that fungicide mixtures used to manage soybean rust can negatively impact an aphid-specific fungal pathogen. However, no consistent soybean aphid population response was observed in these studies of low levels of aphid fungal infection.

Side-effects of pesticides on the life cycle of the mite pathogenic fungus Neozygites floridana.

The tomato red spider mite, Tetranychus evansi Baker and Pritchard, is an invasive species in Africa causing considerable damage to Solanaceous crops. The fungal pathogen Neozygites floridana Weiser and Muma from Brazil has been considered a potential candidate for introduction into Africa for the control of T. evansi. To be incorporated in the tomato production system, N. floridana has to be compatible with the pesticides used for the control of other pests and diseases. Pesticides used in tomatoes that might affect the fungus were therefore studied by the use of different methods. Two insecticides (Lambda-cyhalothrin and Methomyl), two acaricides (Propargite and Abamectin), and two fungicides (Captan and Mancozeb) were tested in two concentrations: the mean commercial rate (CR) and 50% of the mean commercial rate (CR/2). Fungus-killed mite cadavers or the substrates used for sporulation (leaf discs and coverslips) were either immersed or sprayed with the pesticides before testing their effects on sporulation, germination of primary conidia and infectivity of N. floridana. Direct immersion of cadavers, coverslips or leaf discs into pesticides affected sporulation and germination stronger than the spray tower method, although infectivity of capilliconidia was neither affected by the method of application nor the concentration of the pesticides. The fungicides Captan and Mancozeb resulted in a high reduction in sporulation and germination at both concentrations. Propargite did not inhibit sporulation but affected germination of primary conidia. Methomyl and Abamectin resulted in less effects on N. floridana.

Rise and fall of cotton aphid (Hemiptera: Aphididae) populations in southeastern cotton production systems.

The impact of natural enemies on cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), populations in cotton, Gossypium hirsutum L., production systems in the southeastern United States was evaluated over 3 yr in irrigated commercial cotton fields. Fungal epizootics caused by the entomopathogen Neozygites fresenii (Nowakowski) Batko reduced aphid numbers to subthreshold levels in 1999, 2000, and 2001 and occurred consistently in early to mid-July in all 3 yr. Scymnus spp. were the most abundant aphidophagous predators, although other coccinellid species and generalist predators such as spiders, fire ants, heteropterans, and neuropterans also were present. Studies using arthropod exclusion cages demonstrated little impact of predators or parasitoids on aphid populations before fungal epizootics. Arthropod natural enemies were most abundant after epizootics and may have suppressed aphid populations late in the season. Seed cotton yield, and lint quality were not affected by aphicide applications in any year of the study. Implications of these findings for aphid management in the southeastern United States are discussed.

Does methyl salicylate, a component of herbivore-induced plant odour, promote sporulation of the mite-pathogenic fungus Neozygites tanajoae?

Blends of volatile chemicals emanating from cassava leaves infested by the cassava green mite were found to promote conidiation of Neozygites tanajoae, an entomopathogenic fungus specific to this mite. Methyl salicylate (MeSA) is one compound frequently present in blends of herbivore-induced plant volatiles (HIPV) as well as that of mite-infested cassava. Here, we investigated the effect of methyl salicylate in its pure form on the production of pre-infective spores (conidia), and the germination of these spores into infective spores (capilliconidia), by a Brazilian isolate and a Beninese isolate of N. tanajoae. Mummified mites previously infected by the fungal isolates were screened under optimal abiotic conditions for sporulation inside tightly closed boxes with or without methyl salicylate diffusing from a capillary tube. Production of conidia was consistently higher (37%) when the Beninese isolate was exposed to MeSA than when not exposed to it (305.5 +/- 52.62 and 223.2 +/- 38.13 conidia per mummy with and without MeSA, respectively). MeSA, however, did not promote conidia production by the Brazilian isolate (387.4 +/- 44.74 and 415.8 +/- 57.95 conidia per mummy with and without MeSA, respectively). Germination of the conidia into capilliconidia was not affected by MeSA for either isolate (0.2%, 252.6 +/- 31.80 vs. 253.0 +/- 36.65 for the Beninese isolate and 4.2%, 268.5 +/- 37.90 vs. 280.2 +/- 29.43 for the Brazilian isolate). The effects of MeSA on the production of conidia were similar to those obtained under exposure to the complete blends of HIPV for the case of the Beninese isolate, but dissimilar (no promoting effect of MeSA) for the case of the Brazilian isolate. This shows that MeSA, being one compound out of many HIPV, can be a factor promoting sporulation of N. tanajoae, but it may not be the only factor as its effect varies with the fungal isolate under study.

Effects of hydrophilic and hydrophobic kaolin-based particle films on pea aphid (Homoptera: Aphididae) and its entomopathogen Pandora neoaphidis (Entomophthorales: Entomophthoraceae).

Hydrophobic and hydrophilic kaolin-based particle films are effective for control of insect pests in certain agricultural crops. How these products interact with potential biological control agents is not well documented. This study was conducted to evaluate the effects of the hydrophobic (M96-018) and hydrophilic (Surround WP) kaolin-based particle films (Engelhard Corporation, Iselin, NJ) on pea aphid, Acyrthosiphon pisum (Harris), on peas (Pisum spp.), and on the fungal aphid pathogen Pandora neoaphidis (Remaudière and Hennebert) Humber. Over two field seasons (2001 and 2002) in northern Idaho, applications of M96-018 significantly reduced the rate of pea aphid increase on pea, but Surround WP, tested only in 2001, did not reduce aphid population growth rate. Neither particle film treatment was as effective as a standard application of esfenvalerate (DuPont Asana). In the laboratory, particle films suppressed pea aphid populations by up to 30%. M96-018 seemed to have some repellent activity based on aphid distributions after treating plants. When applied along with P. neoaphidis conidia, M96-018 but not Surround WP caused higher percentage of infection mortality of pea aphids by P. neoaphidis than occurred on controls treated only with P. neoaphidis conidia. P. neoaphidis conidia deposited on glass slides coated with M96-018, produced more germ tubes and secondary conidia than those deposited on untreated glass slides or slides treated with Surround WP. This result suggests that greater infection of pea aphids on plants treated with M96-018 is in part a result of a direct enhancement of fungal germination by the particle film.

Response of the entomopathogenic fungus Pandora neoaphidis to aphid-induced plant volatiles.

We used a model plant-aphid system to investigate whether the aphid-specific entomopathogenic fungus Pandora neoaphidis responds to aphid-induced defence by the broad-bean plant, Vicia faba. Laboratory experiments indicated that neither in vivo sporulation, conidia size nor the in vitro growth of P. neoaphidis was affected by Acyrthosiphon pisum-induced V. faba volatiles. The proportion of conidia germinating on A. pisum feeding on previously damaged plants was significantly greater than on aphids feeding on undamaged plants, suggesting a direct functional effect of the plant volatiles on the fungus. However, there were no significant differences in the infectivity of P. neoaphidis towards A. pisum feeding on either undamaged V. faba plants or plants previously infested with A. pisum. Therefore, these results provide no evidence to suggest that P. neoaphidis contributes to plant indirect defence strategies.

Plant waxy bloom on peas affects infection of pea aphids by Pandora neoaphidis.

This study examined the effects of the surface wax bloom of pea plants, Pisum sativum, on infection of pea aphids, Acyrthosiphon pisum, by the fungal pathogen Pandora neoaphidis. In prior field surveys, a higher proportion of P. neoaphidis-killed pea aphids (cadavers) had been observed on a pea line with reduced wax bloom, as compared with a sister line with normal surface wax bloom. Laboratory bioassays were conducted in order to examine the mechanisms. After plants of each line infested with aphids were exposed to similar densities of conidia, the rate of accumulation of cadavers on the reduced wax line was significantly greater than on the normal wax bloom line; at the end of the experiment (13d), the proportion of aphid cadavers on the reduced wax line was approximately four times that on the normal wax bloom line. When plants were exposed to conidia first and then infested with aphids, the rate of accumulation of cadavers was slightly but significantly greater on the reduced wax line, and infection at the end of the experiment (16d) did not differ between the lines. When aphids were exposed first and then released onto the plants, no differences in the proportion of aphid cadavers were observed between the pea lines. Greater infection of pea aphid on reduced wax peas appears to depend upon plants being exposed to inoculum while aphids are settled in typical feeding positions on the plant. Additional experiments demonstrated increased adhesion and germination by P. neoaphidis conidia to leaf surfaces of the reduced wax line as compared with normal wax line, and this could help explain the higher infection rate by P. neoaphidis on the reduced wax line. In bioassays using surface waxes extracted from the two lines, there was no effect of wax source on germination of P. neoaphidis conidia.

Antimicrobial peptide defenses against pathogens associated with global amphibian declines.

Global declines of amphibian populations are a source of great concern. Several pathogens that can infect the skin have been implicated in the declines. The pathogen most frequently associated with recent die-offs is a chytrid fungus, Batrachochytrium dendrobatidis. A second fungus, Basidiobolus ranarum, was isolated from declining populations of Wyoming toads. A third pathogen, Aeromonas hydrophila, is an opportunistic bacterium found in healthy frogs, but capable of inducing disease. Among the immune defense mechanisms used by amphibians is the production of antimicrobial peptides in granular glands in the skin. These packets of natural antibiotics can be emptied onto the skin when the amphibian is injured. To determine whether antimicrobial skin peptides defend against these amphibian pathogens, six peptides (magainin I, magainin II, PGLa, CPF, ranalexin, and dermaseptin), from three species, and representing three structurally different families of peptides, were tested in growth inhibition assays. We show here that the peptides can kill or inhibit growth of both fungi but not Aeromonas. Although each peptide varied in its effectiveness, at least one from each species was effective against both fungi at a concentration of about 10-20 microM. This is the first direct evidence that antimicrobial peptides in the skin can operate as a first line of defense against the organisms associated with global amphibian declines. It suggests that this innate defense mechanism may play a role in preventing or limiting infection by these organisms.

In-vitro antifungal susceptibilities of Basidiobolus and Conidiobolus spp. strains.

The in-vitro antifungal susceptibilities of nine isolates belonging to Basidiobolus spp. and seven to Conidiobolus spp. against six antifungals (amphotericin B, ketoconazole, miconazole, itraconazole, fluconazole and flucytosine) were tested. A broth microdilution method, generally following the NCCLS guidelines, was used. Inoculum concentrations of the order of 100 cfu/mL were obtained by culturing fungi in a broth medium (Czapeck broth supplemented with 2% Tween 80 and 0.07% agar). MICs and MFCs were highly variable and isolate-dependent, with the exception of those of flucytosine which were constantly very high. In general, however, Basidiobolus spp. displayed low MICs of fluconazole, itraconazole, ketoconazole and miconazole, and Conidiobolus spp. were resistant to all antifungals tested.