Co-infection with three mycoviruses stimulates growth of a Monilinia fructicola isolate on nutrient medium, but does not induce hypervirulence in a natural host

Monilinia fructicola and Monilinia laxa are the most destructive fungal species infecting stone fruit (Prunus species). High-throughput cDNA sequencing of M. laxa and M. fructicola isolates collected from stone fruit orchards revealed that 14% of isolates were infected with one or more of three mycoviruses: Sclerotinia sclerotiorum hypovirus 2 (SsHV2, genus Hypovirus), Fusarium poae virus 1 (FPV1, genus Betapartitivirus), and Botrytis virus F (BVF, genus Mycoflexivirus). Isolate M196 of M. fructicola was co-infected with all three viruses, and this isolate was studied further. Several methods were applied to cure M196 of one or more mycoviruses. Of these treatments, hyphal tip culture either alone or in combination with antibiotic treatment generated isogenic lines free of one or more mycoviruses. When isogenic fungal lines were cultured on nutrient agar medium in vitro, the triple mycovirus-infected parent isolate M196 grew 10% faster than any of the virus-cured isogenic lines. BVF had a slight inhibitory effect on growth, and FPV1 did not influence growth. Surprisingly, after inoculation to fruits of sweet cherry, there were no significance differences in disease progression between isogenic lines, suggesting that these mycoviruses did not influence the virulence of M. fructicola on a natural host

Effect of Inclusion of Fresh or dried black soldier fly larvae in Diets on Snakehead Fish's Growth Performance and Chemical Composition (<em>Channa sp.</em>)

In snakehead fish farming, feeding represents the largest portion (accounting for 50-60%) of production cost. Thus, finding an alternative natural feed that can be replaced as full or partial inclusion in snakehead fish commercial diets is urgently needed. This study was carried out to evaluate the effect of including fresh or dried black soldier fly larvae (BSFL) in diets on the growth performance and chemical composition of snakehead fish cultured in small-scale farms. Fingerlings of snakehead (5.15 ± 0.12 g) were distributed randomly into fifteen net cages (6 m^3^) at a density of 120 fish.net cage^-1^. Including five dietary treatments named: NT1 (100% commercial feed served as a control); NT2 (100% fresh BSFL); NT3 (100% dried BSFL); NT4 (50% fresh BSFL + 50% commercial feed); and NT5 (50% dried BSFL + 50% commercial feed). Each treatment was performed in triplicate. The results showed that the inclusion of fresh BSFL in diets for the snakehead fish did not affect the survival rate (82.22 - 85.56 %), improved feed conversion ratio, increased live weight (70.9 – 103.3 g) and daily weight gain (1.09 – 1.64 g.day^-1^), and fish’s yield (1.16 – 1.73 kg.m^-2^); and did not affect the chemical composition of the fish. These findings suggest that farmers should feed snakehead fish with commercial feed plus fresh black soldier fly larvae to maintain good condition factor and enhance fish growth performance and production

Fresnel laws at curved dielectric interfaces of microresonators

We discuss curvature corrections to Fresnel's laws for the reflection and transmission of light at a non-planar refractive-index boundary. The reflection coefficients are obtained from the resonances of a dielectric disk within a sequential-reflection model. The Goos-H\"anchen effect for curved light fronts at a planar interface can be adapted to provide a qualitative and quantitative extension of the ray model which explains the observed deviations from Fresnel's laws.Comment: submitted to Phys. Rev.

Severity influences categorical likelihood communications: A case study with Southeast Asian weather forecasters

Risk assessments are common in multiple domains, from finance to medicine. They require evaluating an event's potential severity and likelihood. We investigate the possible dependence of likelihood and severity within the domain of impact-based weather forecasting (IBF), following predictions derived from considering asymmetric loss functions. In a collaboration between UK psychologists and partners from four meteorological organisations in Southeast Asia, we conducted two studies (N = 363) eliciting weather warnings from forecasters. Forecasters provided warnings denoting higher likelihoods for high severity impacts than low severity impacts, despite these impacts being described as having the same explicit numerical likelihood of occurrence. This 'Severity effect' is pervasive, and we find it can have a continued influence even for an updated forecast. It is additionally observed when translating warnings made on a risk matrix to numerical probabilities

Four Tulasnella taxa associated with populations of the Australian evergreen terrestrial orchid Cryptostylis ovata

Of the more than 400 indigenous orchid species in Western Australia, Cryptostylis ovata is the only species that retains its leaves all year round. It exists as a terrestrial herb and occasionally as an epiphyte in forested areas. Like all terrestrial orchids, C. ovata plants associate with mycorrhizal fungi, but their identities have not previously been investigated. Fungi were isolated from pelotons in rhizomes collected from three southern and two northern populations of C. ovata on six occasions over two years. Phylogenetic analysis of ITS sequences temporally and spatially revealed that all the fungal isolates were of Tulasnella species of four distinct groups. One Tulasnella group was present only in the three southern orchid populations, and it closely resembled T. prima isolates previously described from Chiloglottis sp. orchids from eastern Australia. Isolates collected from plants in the two northern populations were of three undescribed Tulasnella groups. Analysis of intra-group diversity using inter-simple sequence repeat markers revealed that plants were usually colonised by a single genotype of Tulasnella at each sampling period, and this genotype usually, but not always, persisted with the host plant over both years tested

Monilinia fructicola and Monilinia laxa isolates from stone fruit orchards sprayed with fungicides displayed a broader range of responses to fungicides than those from unsprayed orchards

Monilinia fructicola and Monilinia laxa are causal agents of brown rot, the most serious fungal disease of stone fruit (Prunus species). The disease is controlled primarily by applying fungicides. It was hypothesised that Monilinia isolates exposed to a regime of fungicidal sprays would exhibit greater tolerance to those compounds than isolates that had not been subjected at all to such fungicide sprays. Sixty-six M. fructicola and 52 M. laxa isolates were collected from fungicide-sprayed and unsprayed commercial and domestic orchards. The fungicides propiconazole, iprodione, and a mixture of fluopyram and trifloxystrobin were used regularly on all the sprayed orchards tested, and these were used to challenge all Monilinia isolates in vitro. We found that isolates collected from sprayed orchards were on average more tolerant to the fungicides, as measured by effective concentration of fungicide reducing mycelial growth by 50% (EC50). This trend was evident for both fungal species tested, but it was statistically significant only for M. fructicola. Monilinia laxa isolates were on average more tolerant to propiconazole than were M. fructicola isolates irrespective of orchard type, while average responses to iprodione and fluopyram + trifloxystrobin were similar for both species. Although tolerant and sensitive isolates were identified under both sprayed and unsprayed regimes, there was a greater range of responses to all three fungicides by isolates from sprayed orchards. Isolates with tolerance to two fungicides were not exclusively from sprayed orchards, but occurred more frequently there

Genotypic structure of Monilinia populations in Western Australia two decades after incursion

In 1997, Monilinia fructicola and Monilinia laxa, fungi causing brown rot disease in stone fruit (Prunus species), were identified from Western Australia for the first time. Up until then, Monilinia were quarantine species, and importation of stone fruits to W.A. was prohibited. After Monilinia was identified in W.A., importation of stone fruit from sources outside W.A. was progressively permitted. Today, Monilinia is present in all stone fruit production regions in W.A. The aim of this study was to determine if the genotypes responsible for the first incursion subsequently spread, or if new genotypes have since become established. ISSR markers were used to identify the genotype of isolates collected during the initial incursion event in 1997, and compare them with isolates collected subsequently. Eight M. fructicola genotypes were identified, including a monotypic one on a fresh peach imported from the USA. M. fructicola isolates collected during the initial incursion in 1997 and an isolate from cherry collected in South Australia in the same year were all of the same genotype, suggesting fruit or germplasm from S.A. as the source of the W.A. incursion. However, this incursion genotype appears not have persisted, with different genotypes subsequently becoming widely or locally established. Four genotypes of M. laxa were identified. In contrast to M. fructicola, the 1997 incursion genotype of M. laxa has become widely established in W.A., infecting both stone fruits and pome fruits

Spatial distribution of Monilinia fructicola and M. laxa in stone fruit production areas in Western Australia

In 2016 and 2017, 90 fungal isolates were collected from Prunus species exhibiting symptoms of brown rot disease at 12 sites in stone fruit production areas in Western Australia. ITS region analysis showed that 49 isolates belonged to Monilinia laxa and 34 to M. fructicola, species that cause brown rot in stone fruit. The two species were spatially separated to the south of the Perth Hills region, where only M. laxa was found, and to the north of Perth Hills where only M. fructicola was found. The two species co-existed only in the Perth Hills. The implications for control and trade are discussed, as is the need to implement biosecurity guidelines to prevent mixing of the two species where currently only one exists