Foraging behavior and bait station preference in scavenging termite, Odontotermes obesus (Blattodea: Termitidae)

Termites are a significant pest of buildings, agriculture, and trees, and are mainly controlled by baiting. However, baiting systems are available for only lower termites (Rhinotermitidae) not for higher termites (Termitidae). Termite foraging behavior associated with baiting systems varies among species and families, and plays a significant role in baiting success. Here, foraging behavior of Odontotermes obesus (Blattodea: Termitidae: Macrotermitinae), a fungus-growing higher termite, was investigated relative to three bait-station sizes (small, medium, and large) containing different quantities of food. Significantly more workers recruited to large stations (470/station) compared to medium (246/station) and small (124/station) stations. Abundance of O. obesus in large and medium stations significantly positively correlated with relative humidity whereas negative but non-significant correlations were observed with temperature in large and medium stations. Total and continuous contacts with the stations increased with time and were greater in large stations. Station abandonment due to disturbance was significantly less in large stations (3%) followed by medium (9%) and small stations (20%). Our results suggest that large stations (≈8 litres volume) work best for population management of O. obesus and other related fungus-growing higher termites.

Occurrence of Stenocarpella macrospora Causing Ear Rot in Corn in the United States

Diplodia ear rot of corn is primarily caused by the fungus Stenocarpella maydis in the United States. Stenocarpella macrospora is a closely related fungus present in the U.S. but primarily associated with Diplodia leaf streak. S. macrospora is recognized as a major ear rot pathogen in South America and South Africa, but has infrequently been associated with ear rot in the U.S. This brief presents the first reports of Diplodia ear rot in Illinois and Tennessee. This is also the first confirmation of S. macrospora causing ear rot in the U.S. in over 60 years. Accepted for publication 19 May 2016. Published 15 June 2016.

Specificity in the symbiotic association between fungus-growing ants and protective Pseudonocardia bacteria

Fungus-growing ants (tribe Attini) engage in a mutualism with a fungus that serves as the ants' primary food source, but successful fungus cultivation is threatened by microfungal parasites (genus Escovopsis ). Actinobacteria (genus Pseudonocardia ) associate with most of the phylogenetic diversity of fungus-growing ants; are typically maintained on the cuticle of workers; and infection experiments, bioassay challenges and chemical analyses support a role of Pseudonocardia in defence against Escovopsis through antibiotic production. Here we generate a two-gene phylogeny for Pseudonocardia associated with 124 fungus-growing ant colonies, evaluate patterns of ant– Pseudonocardia specificity and test Pseudonocardia antibiotic activity towards Escovopsis . We show that Pseudonocardia associated with fungus-growing ants are not monophyletic: the ants have acquired free-living strains over the evolutionary history of the association. Nevertheless, our analysis reveals a significant pattern of specificity between clades of Pseudonocardia and groups of related fungus-growing ants. Furthermore, antibiotic assays suggest that despite Escovopsis being generally susceptible to inhibition by diverse Actinobacteria, the ant-derived Pseudonocardia inhibit Escovopsis more strongly than they inhibit other fungi, and are better at inhibiting this pathogen than most environmental Pseudonocardia strains tested. Our findings support a model that many fungus-growing ants maintain specialized Pseudonocardia symbionts that help with garden defence.

Fatal Ophiostoma piceae infection in a patient with acute lymphoblastic leukaemia

We report to our knowledge the first case of human infection with Ophiostoma piceae. This Sporothrix schenckii-related fungus caused disseminated infection involving the lung and the brain in a patient with lymphoblastic lymphoma. The case emphasizes the significance of molecular techniques for identification of rare fungi in the clinical microbiology laboratory.

Identification and Characterization of MFA1, the Gene Encoding Candida albicansa-Factor Pheromone

ABSTRACT In the opaque state, MTL a and MTLα strains of Candida albicans are able to mate, and this mating is directed by a pheromone-mediated signaling process. We have used comparisons of genome sequences to identify a C. albicans gene encoding a candidate a-specific mating factor. This gene is conserved in Candida dubliniensis and is similar to a three-gene family in the related fungus Candida parapsilosis but has extremely limited similarity to the Saccharomyces cerevisiae MFA1 (ScMFA1) and ScMFA2 genes. All these genes encode C-terminal CAAX box motifs characteristic of prenylated proteins. The C. albicans gene, designated CaMFA1, is found on chromosome 2 between ORF19.2165 and ORF19.2219. MFA1 encodes an open reading frame of 42 amino acids that is predicted to be processed to a 14-amino-acid prenylated mature pheromone. Microarray analysis shows that MFA1 is poorly expressed in opaque MTL a cells but is induced when the cells are treated with α-factor. Disruption of this C. albicans gene blocks the mating of MTL a cells but not MTLα cells, while the reintegration of the gene suppresses this cell-type-specific mating defect.

Cultural and PCR-based identification of the two most common fungi from cankers on container-grown Norway spruce seedlings

Assays were made to identify the most common fungi in cankers occurring on container seedlings of Norway spruce. The fungi isolated from cankers were first separated into morphological groups based on colony color, growth rate, and pattern on malt extract agar. Profiling of 18S rDNA indicated that several operational taxonomic units (OTUs) inhabited the cankers, some (OTU1 and OTU2) of which could be linked to mycelial cultures also isolated from the cankers. In addition, OTU1 could be linked to isolates originating from damped-off seedlings. Although the cultures linked to OTU1 differed morphologically from each other, the random amplified microsatellite analysis showed that they were genetically highly similar and represented a single species. Later, when these cultures were kept in natural sunlight, they all produced conidia morphologically similar to Sirococcus conigenus. Also, their partial 18S rDNA sequence was identical to that of S. conigenus in GenBank. The other common fungus (OTU2) was not possible to identify to species level, but based on comparisons with sequences in GenBank, it was closely related to Phoma herbarum. In preliminary tests, both S. conigenus (OTU1) and P. herbarum related fungus (OTU2) were pathogenic to Norway spruce seedlings.

287 IMPROVED PERFORMANCE OF SHRUNKEN-2 SWEET CORN USING TRICHODERM HARZIANUM AS A BIOPROTECTANT

A strain of the biocontrol fungus Trichoderma harzianum was tested for effectiveness in improving the performance of sh2 sweet corn using a variety of delivery methods. In greenhouse trials, Trichoderma seed treatment reduced the proportion of weak plants (unlikely to make a marketable ear) from 40% to 10%. This is evidence that the characteristically uneven stand establishment of supersweet corn should be overcome by using Trichoderma. In field trials, Trichoderma and Gliocladium (a related fungus) were inoculated as a seed treatment without fungicide in spring-tilled plots. Yields of uninoculated controls were 2.2, Gliocladium-treated were 2.6, and Trichoderma -treated were 3.6 T/ac. Delivering the same lines of fungus in the fall to a rye cover crop resulted in high populations the following spring. The cover crop was killed and fungicide-treated seed of `Zenith' sweet corn was planted without tillage. Yield with Trichoderma was 4.0, with Gliocladium was 3.7, and uninoculated was 2.4 T/at. The uninoculated, conventionally-tilled plots also yielded 4 T/at. Thus the beneficial fungi overcame the inhibition caused by no-till. Trichoderma was delivered effectively both as a seed treatment and on a winter cover crop to improve stand uniformity and overall yield.