A positive locality record or Lepidiota Contigua Britton (Coleoptera: Scarabaeidae: Melolonthinae)

Lepidiota contigua Britton is recorded from Windsor Tableland, northern Queensland.

Production locality influences postharvest disease development and quality in mangoes

Postharvest disease management is one of the key challenges in commercial mango supply chains. Comprehensive investigations were made regarding the impact of geographic locality on postharvest disease development and other quality parameters in 'Sindhri' and 'Samar Bahisht (S.B.) Chaunsa' mangoes under ambient (33±1°C; 55-60% RH) and low temperature storage/simulated shipping (12±1°C; 80- 85% RH) conditions (28 or 35 days storage for 'Sindhri' and 21 or 28 days for 'S.B. Chaunsa'). Physiologically mature (days from fruit set were 95-100 and 110-115 for 'Sindhri' and 'S.B Chaunsa', respectively) 'Sindhri' and 'S.B. Chaunsa' fruits were harvested from five geographic localities and subjected to ambient and simulated shipping conditions. Under ambient conditions, no disease incidence was observed till fruit eating stage in 'Sindhri'. However, in 'S.B. Chaunsa', significant variation in different localities was observed with respect to disease incidence. Maximum and at par disease was exhibited by the fruit collected from district Vehari and Khanewal in 'S.B. Chaunsa'. Under simulated shipping conditions, disease development varied significantly with respect to different locations and storage durations. In 'Sindhri', fruit of M. Garh, while, 'S.B. Chaunsa' fruit of districts R.Y. Khan, M. Garh and Khanewal showed higher disease incidence. Fruit peel colour development was significantly reduced as storage days increased. Fruit firmness, skin shriveling, fresh weight loss, dry matter, biochemical and organoleptic attributes also varied significantly among the fruit sourced from different orchards of different localities. Analysis of N contents in leaves and fruit peel revealed that N contents of leaf and peel were positively correlated with disease severity in mango. Botryodiplodia spp., Phomopsis mangiferae, Alternaria alternata, Colletotrichum gloeosporioides were the pathogens isolated from fruits of all locations; however, the prevalence frequency varied with the geographic localities. In conclusion, the production locality, cultivar and nutrition (nitrogen content of fruit peel) had significant effect on fruit quality out-turn at ripe stage in terms of disease development so area specific disease management system needs to be implemented for better quality at retail.

Assessment of internal quality attributes of mandarin fruit. 2. NIR calibration model robustness

The robustness of multivariate calibration models, based on near infrared spectroscopy, for the assessment of total soluble solids (TSS) and dry matter (DM) of intact mandarin fruit (Citrus reticulata cv. Imperial) was assessed. TSS calibration model performance was validated in terms of prediction of populations of fruit not in the original population (different harvest days from a single tree, different harvest localities, different harvest seasons). Of these, calibration performance was most affected by validation across seasons (signal to noise statistic on root mean squared error of prediction of 3.8, compared with 20 and 13 for locality and harvest day, respectively). Procedures for sample selection from the validation population for addition to the calibration population (‘model updating’) were considered for both TSS and DM models. Random selection from the validation group worked as well as more sophisticated selection procedures, with approximately 20 samples required. Models that were developed using samples at a range of temperatures were robust in validation for TSS and DM.

Epitypification and phylogeny of Colletotrichum acutatum J.H. Simmonds

Simmonds introduced Colletotrichum acutatum in 1965, validated in 1968, with a broad concept, as demonstrated by the selection of several type specimens from a range of hosts. This has created some confusion in the species concept and identification of C. acutatum. There are no viable ex-type cultures of C. acutatum and furthermore there are no existing cultures of C. acutatum on Carica papaya from the type locality in south-east Queensland. The application of molecular phylogenetic studies to isolates of C. acutatum is only meaningful if the taxonomy is stable and species are properly named. In order to clarify the species concept of C. acutatum, an isolate of Colletotrichum acutatum from Carica papaya from Yandina in Southeast Queensland (Australia) is designated as an epitype. A detailed morphological description is provided. Phylogenies based on a combined ITS and beta-tubulin gene analysis indicate that C. acutatum bears close phylogenetic affinities to C. gloeosporioides and C. capsici. Results also indicate that C. acutatum is monophyletic and there is a close relationship between the epitype and other Australian C. acutatum isolates from Carica papaya. Molecular data, however did not provide further evidence to properly elucidate the taxonomie affinities of C. acutatum especially the holotype and epitype. Our studies indicate that given the complexity of the genus Colletotrichum, there is a need to check previously described type specimens and redesign neotypes where necessary in order to clarify taxonomie uncertainties.

The distribution and spread of citrus canker in Emerald, Australia

Citrus canker is a disease of citrus and closely related species, caused by the bacterium Xanthomonas citri subsp. citri. This disease, previously exotic to Australia, was detected on a single farm [infested premise-1, (IP1). IP is the terminology used in official biosecurity protocols to describe a locality at which an exotic plant pest has been confirmed or is presumed to exist. IP are numbered sequentially as they are detected] in Emerald, Queensland in July 2004. During the following 10 months the disease was subsequently detected on two other farms (IP2 and IP3) within the same area and studies indicated the disease first occurred on IP1 and spread to IP2 and IP3. The oldest, naturally infected plant tissue observed on any of these farms indicated the disease was present on IP1 for several months before detection and established on IP2 and IP3 during the second quarter (i.e. autumn) 2004. Transect studies on some IP1 blocks showed disease incidences ranged between 52 and 100% (trees infected). This contrasted to very low disease incidence, less than 4% of trees within a block, on IP2 and IP3. The mechanisms proposed for disease spread within blocks include weather-assisted dispersal of the bacterium (e.g. wind-driven rain) and movement of contaminated farm equipment, in particular by pivot irrigator towers via mechanical damage in combination with abundant water. Spread between blocks on IP2 was attributed to movement of contaminated farm equipment and/or people. Epidemiology results suggest: (i) successive surveillance rounds increase the likelihood of disease detection; (ii) surveillance sensitivity is affected by tree size; and (iii) individual destruction zones (for the purpose of eradication) could be determined using disease incidence and severity data rather than a predefined set area.

Revisiting genetic structuring in spotted gums (genus Corymbia section Maculatae) focusing on C. maculata, an early diverged, insular lineage

Species delineation in the spotted gum complex was revisited focusing on Corymbia maculata. This study expands the range of C. maculata analysed with microsatellite markers to include populations from the north of the species range. It supported earlier findings that it is a cohesive genetic entity, well resolved from northern spotted gum taxa, Corymbia citriodora and Corymbia henryi; and inferences that its insularity is due to early lineage divergence and historical isolation. The northern extent of C. maculata sampled, as defined by chloroplast and nuclear genomes predominantly of C. maculata character, was the location of Kiwarrak, south of the Manning River near Taree in New South Wales. Trees from a recognised intergrade zone at the Yarratt locality, around 26 km north of Kiwarrak, also possessed a uniquely C. maculata chloroplast haplotype, but their nuclear genomes were predominantly of northern taxa ancestry. Range expansion of northern taxa leading to southerly gene movement into populations formerly C. maculata, would account for this apparent instance of chloroplast capture. Two subpopulations were identified in C. maculata, a northern population of which the Ourimbah locality was the most southerly studied, and a southern population of which Wingello was the most northerly locality studied. Diminished levels of northern taxa ancestry, i.e. C. citriodora or C. henryi, in individuals from the southern, relative to the northern subpopulation of C. maculata, suggested that secondary contact with northern taxa contributes to its substructure.

Lesser auger beetle Heterobostrychus aequalis(Coleoptera: Bostrichidae) in Australia: absent or elusive?

The lesser auger beetle, Heterobostrychus aequalis (Waterhouse), is a serious pest of seasoned hardwood timber throughout the Oriental region and several areas beyond. Some early collection records of H. aequalis from Australia in the 1950s and 1960s indicated that the insect was present in northern Queensland, but no confirmed breeding population has been found in the past few decades suggesting either that it may have not established permanently or it is difficult to detect. The ambiguity about the breeding status of the pest in Australia has caused confusion for regulating authorities needing to respond to each new post-border detection. We examined records of H. aequalis in Australian insect collections and from intensive plant pest surveillance activities in Queensland and northern Australia over the past 48 years to resolve this confusion. Until very recently, available evidence suggested that H. aequalis was not established in Australia, despite multiple introductions and apparently suitable climate and hosts. Collection records of the pest are predominantly linked to intercepted items or are recorded as of unknown origin, and no established populations have been found during many years of targeted surveillance. However, a detection of H. aequalis in suburban Cairns, north Queensland, in late 2013 and two more in mid-2015 in the same general locality do not appear to be linked to any imported material, indicating that there is at least a tenuously established local population. Investigations are underway to confirm this, but the insect is not widely established in Australia and, if present, remains elusive. Our recommended response to any future detection of H. aequalis is to fumigate or destroy the infested material, conduct tracing enquiries and limit surveys to the immediate vicinity of the detection.