Prosopidicola mexicana gen. et sp. nov., causing a new pod disease of Prosopis species

Species of Prosopis introduced into South Africa from the Americas for fuel wood, shade and fodder, have become naturalized and widespread in the dry northwestern areas of this country. Invasive Prosopis species have been the target of a biological control programme in South Africa since 1985. During a survey for potential fungal biological control agents in Mexico and Texas in 2001, a pod disease was recorded on Prosopis glandulosa in both countries. The disease is characterized by black/grey pycnidia, flattening of the pods, and seed decay. Morphological investigations of the causal organism showed it to be a Coniothyrium-like, coelomycete. However, based on conidiogenous cell morphology and proliferation, we concluded that the organism is not congeneric with Coniothyrium s. str. Phylogenetic analysis of the SSU gene placed this fungus in the Diaporthales. Parsimony analysis of the ITS region (ITS-1, 5.8S, ITS-2) revealed it to group closely to Cryphonectria and Endothia. Consequently, a new genus, Prosopidicola, with type species Prosopidicola mexicana, is proposed

2022 Upgrade and Improved Low Frequency Camera Sensitivity for CMB Observation at the South Pole

Constraining the Galactic foregrounds with multi-frequency Cosmic Microwave Background (CMB) observations is an essential step towards ultimately reaching the sensitivity to measure primordial gravitational waves (PGWs), the sign of inflation after the Big-Bang that would be imprinted on the CMB. The BICEP Array telescope is a set of multi-frequency cameras designed to constrain the energy scale of inflation through CMB B-mode searches while also controlling the polarized galactic foregrounds. The lowest frequency BICEP Array receiver (BA1) has been observing from the South Pole since 2020 and provides 30 GHz and 40 GHz data to characterize the Galactic synchrotron in our CMB maps. In this paper, we present the design of the BA1 detectors and the full optical characterization of the camera including the on-sky performance at the South Pole. The paper also introduces the design challenges during the first observing season including the effect of out-of-band photons on detectors performance. It also describes the tests done to diagnose that effect and the new upgrade to minimize these photons, as well as installing more dichroic detectors during the 2022 deployment season to improve the BA1 sensitivity. We finally report background noise measurements of the detectors with the goal of having photon noise dominated detectors in both optical channels. BA1 achieves an improvement in mapping speed compared to the previous deployment season.Comment: Proceedings of SPIE Astronomical Telescopes + Instrumentation 2022 (AS22

Predicting the distribution of Endophyllum osteospermi (Uredinales, Pucciniaceae) in Australia based on its climatic requirements and distribution in South Africa

The perennial bush Chrysanthemoides monilifera ssp. monilifera (Asteraceae) is infected by the autoecious, microcyclic rust fungus Endophyllum osteospermi. Both organisms are native to South Africa, whilst the plant has also become naturalised in Australia where it is the target of a biological control program. E. osteospermi is under consideration as a biocontrol agent for this weed. Temperature and light requirements for aecidioid teliospore germination and basidiospore development were studied, as was the nuclear cycle during germination. Aecidioid teliospores germinated between 10 and 20°C, with 15°C as optimum temperature. Light, and particularly near-UV light, stimulated germination whereas germination was poor under dark conditions. A period of 6-8 h of light was the minimum needed to obtain germination levels equivalent to continuous light. The temperature requirements for basidiospore development differed from that for aecidioid teliospore germination. Optimal basidiospore production was at 15°C, but a rapid decrease occurred at higher temperatures, with few developing at 19°C, despite a high germination rate at this temperature. Two nuclear divisions occurred within 12 h of germination initiation to produce a metabasidium with three or four nuclei. A third nuclear division occurred in the basidiospores that then germinated between 24 and 48 h. Plants inoculated under controlled conditions took 5 to 24 months after inoculation for witches' broom symptoms to begin to develop. The detailed life cycle of E. osteospermi is presented. A Geographic Information System (GIS) approach was used to develop a model of the potential distribution of E. osteospermi in South Africa. This was based on monthly average climate surfaces with parameters derived from the above experiments. The parameters were modified so that the majority of all recorded localities of E. osteospermi in South Africa were included, whilst at the same time including only the minimum geographic area. The same model was applied to Australia to suggest a potential distribution of the rust fungus if released in Australia for the biological control of C. monilifera ssp. monilifera. This potential distribution was similar to one generated using the climate matching computer program CLIMEX, but gave greater spatial accuracy, at least in South Africa. Both approaches indicate that E. osteospermi should establish in temperate south-eastern Australia where C. monilifera ssp. monilifera is an invasive weed.Articl

Infection of Table Grape Bunches by Alternaria alternata

Infection of table grape bunches by Alternaria alternaJa was investigated by light, fluorescence and scanning electron microscopy. Conidia in 20-μ1 drops of spore suspension germinated readily on the fruit surface and within 16 h grew extensively on berries, pedicels and rachises of immature and mature bunches. Appressoria were formed within 16 hat the tip of germ tubes and hyphae, and on short side branches on the different bunch parts, but no evidence of direct penetration was found. The pathogen penetrated the host tissue through stomata, lenticels and microcracks in the epidermis. Infection hyphae remained localized in the substomatal cavities or surface cells oflenticels, and were restricted to a few epidermal cells in the case of epidermal microcracks, but caused no cell necrosis.  Under conditions of high humidity, the fungus grew out of the stomata, lenticels and microcracks and formed an extensive superficial growth within 168 h. Although the fungus was able to grow into epidermal cells adjacent to those surrounding wounds, it would appear that this process is a slow one. The behaviour of A.  alternala partly explains the extensive superficial growth of the pathogen that may occur on rachises and pedicels of table grapes at the end of the cold storage period

Predicting the distribution of Endophyllum osteospermi (Uredinales, Pucciniaceae) in Australia based on its climatic requirements and distribution in South Africa

The perennial bush Chrysanthemoides monilifera ssp. monilifera (Asteraceae) is infected by the autoecious, microcyclic rust fungus Endophyllum osteospermi. Both organisms are native to South Africa, whilst the plant has also become naturalised in Australia where it is the target of a biological control program. E. osteospermi is under consideration as a biocontrol agent for this weed. Temperature and light requirements for aecidioid teliospore germination and basidiospore development were studied, as was the nuclear cycle during germination. Aecidioid teliospores germinated between 10 and 20°C, with 15°C as optimum temperature. Light, and particularly near-UV light, stimulated germination whereas germination was poor under dark conditions. A period of 6¿8 h of light was the minimum needed to obtain germination levels equivalent to continuous light. The temperature requirements for basidiospore development differed from that for aecidioid teliospore germination. Optimal basidiospore production was at 15°C, but a rapid decrease occurred at higher temperatures, with few developing at 19°C, despite a high germination rate at this temperature. Two nuclear divisions occurred within 12 h of germination initiation to produce a metabasidium with three or four nuclei. A third nuclear division occurred in the basidiospores that then germinated between 24 and 48 h. Plants inoculated under controlled conditions took 5 to 24 months after inoculation for witches¿ broom symptoms to begin to develop. The detailed life cycle of E. osteospermi is presented. A Geographic Information System (GIS) approach was used to develop a model of the potential distribution of E. osteospermi in South Africa. This was based on monthly average climate surfaces with parameters derived from the above experiments. The parameters were modified so that the majority of all recorded localities of E. osteospermi in South Africa were included, whilst at the same time including only the minimum geographic area. The same model was applied to Australia to suggest a potential distribution of the rust fungus if released in Australia for the biological control of C. monilifera ssp. monilifera. This potential distribution was similar to one generated using the climate matching computer program CLIMEX, but gave greater spatial accuracy, at least in South Africa. Both approaches indicate that E. osteospermi should establish in temperate south-eastern Australia where C. monilifera ssp. monilifera is an invasive wee

Selenophoma eucalypti and Stigmina robbenensis spp. nov. from Eucalyptus leaves on Robben Island

[No abstract available]Articl