In vitro rearing of Perkinsiella saccharicida and the use of leaf segments to assay Fiji disease virus transmission

Fiji leaf gall (FLG) is caused by the Reovirus, Fiji disease virus (FDV), which is transmitted to sugarcane by planthoppers of the genus Perkinsiella. Low vector transmission rates and slow disease symptom development make experimentation within the FDV-Perkinsiella-sugarcane system inherently difficult. A laboratory-based technique was devised to rear the vector using sugarcane leaves as a food source. Planthoppers were reared on sugarcane leaf segments embedded in agarose enclosed within plastic containers. To provide a nondestructive assay for determination of the inoculation potential of planthoppers, FDV was detected by reverse transcription-polymerase chain reaction (RT-PCR) in newly infected sugarcane leaf segments following exposure to viruliferous planthoppers. Leaf segment inoculation correlated with development of FLG symptoms in whole plants that were fed on by the same planthoppers. Analysis of FDV RNAs within the planthopper, measured by quantitative RT-PCR (qRT-PCR), indicated that FDV RNA concentration was associated with successful inoculation of the leaf segment, transmission of FDV to sugarcane and subsequent development of FLG in plants. Quantification of FDV RNA within planthoppers provided an additional measure to assess vector competence in individuals.

Sugarcane moth borers (Lepidoptera: Noctuidae and Pyraloidea): phylogenetics constructed using COII and 16S mitochondrial partial gene sequences

Sugarcane moth borers are a diverse group of species occurring in several genera, but predominately within the Noctuidae and Pyraloidea. They cause economic loss in sugarcane and other crops through damage to stems and stalks by larval boring. Partial sequence data from two mitochondrial genes, COII and 16S, were used to construct a molecular phylogeny based on 26 species from ten genera and six tribes. The Noctuidae were found to be monophyletic, providing molecular support for the taxonomy within this subfamily. However, the Pyraloidea are paraphyletic, with the noctuids splitting Galleriinae and Schoenobiinae from the Crambinae. This supports the separation of the Pyralidae and Crambinae, but does not support the concept of the incorporation of the Schoenobiinae in the Crambidae. Of the three crambine genera examined, Diatraea was monophyletic, Chilo paraphyletic, and Eoreuma was basal to the other two genera. Within the Noctuidae, Sesamia and Bathytricha were monophyletic, with Busseola basal to Bathytricha. Many species in this study (both noctuids and pyraloids) had different biotypes within collection localities and across their distribution; however the individual biotypes were not phylogenetically informative. These data highlight the need for taxonomic revisions at all taxon levels and provide a basis for the development of DNA-based diagnostics for rapidly identifying many species at any developmental stage. This ability is vital, as the species are an incursion threat to Australia and have the potential to cause significant losses to the sugar industry.

Overwintering, soil distribution and phenology of Childers canegrub, Antitrogus parvulus (Coleoptera: Scarabaeidae) in Queensland sugarcane

In this study, the question of whether Childers canegrub, Antitrogus parvulus (Britton) overwinters in the subsoil was addressed. Irrigated fields of sugarcane were sampled during a 2-year period near Bundaberg in southern Queensland. Antitrogus parvulus overwintered as second and third instars at each of three sites. During autumn and winter third instars of different allochronic (separated in age by 12 months) populations occurred together and could not be readily separated. Field-collected third instars were reared on ryegrass and separated into two age groups based on the date of pupation. Third instars in the first year of their life cycle (young third instars) remained at shallow depth (100-200 mm) and did not overwinter in the subsoil as once thought. Minimum temperatures during winter were 13-16 degrees C and did not prevent young third instars from feeding and gaining weight. Third instars in their second and final year moved downwards from late summer and pupated in the subsoil at 293-425 mm in spring. General phenology was as previously reported with first instar larvae occurring from January until April, second instars from January until November and third instar larvae throughout the year. Prepupae and pupae were found between October and December and adults occurred in soil during November and January. Batches of eggs occurred at a mean depth of 350 mm. First and second instars occurred predominantly at relatively shallow (100-200 mm) depths in the soil profile. All stages tended to be most common under rows of sugarcane rather than in the interrow.

Identification of Australian canegrubs (Coleoptera : Scarabaeidae : Melolonthini)

Larvae of Melolonthini are commonly known as whitegrubs or, in the Australian sugar industry, as canegrubs. In Australia, there are 119 recognised species of Melolonthini, of which 75 are found in Queensland. Of the 75 species, this study examines 19 species that are recognised sugarcane pests. These belong to the genera Antitrogus Burmeister, Dermolepida Arrow, Lepidiota Kirby and Rhopaea Erichson. Descriptions of adults and larvae of the 19 species are provided in this paper, as well as species identification keys for both adults and larvae and a key to the tribes, as a premise for introducing more effective management strategies. Identification of canegrubs is pertinent because the various species have different ecologies, behaviours and insecticide susceptibilities, and their control requires different methods and rates of application of insecticides. We have separated larvae of the species on the basis of their raster pattern, locality and, where necessary, head width. Larvae of some species are difficult to identify and we suggest use of molecular tools for their identification.

Integrated management of canegrubs in Australia: current situation and future research directions

Nineteen species of scarab larvae, collectively known as canegrubs, attack the root system of sugarcane in Australia. Thousands of hectares of sugarcane were damaged before the introduction of organochlorine insecticides in 1948. A controlled-release formulation of chlorpyrifos (suSCon Blue) and a non-residual formulation of ethoprophos (Mocap) replaced the organochlorines in the 1980s. Recent failures of both these products in some fields have intensified the search for alternative controls. This review covers the current knowledge of canegrub biology, ecology and control in Australia. An outline of research required to develop sustainable pest management for canegrubs is given. Knowledge of the population dynamics of canegrubs will be integrated with cultural, chemical and biological controls as appropriate for each pest in each region. A decision-support system will help pest managers to make appropriate choices.

Revision of the Pachytrichini (Coleoptera : Scarabaeidae : Melolonthinae)

The monogeneric tribe, Pachytrichini, is revised and five species, all from Western Australia, are recognised: Pachytricha castanea Hope, P. demarzi Frey, P. minor Sharp, P. robusta Sharp, and P. tecta Sharp. P. munda Sharp and P. pallens Sharp are considered junior synonyms of P. castanea.

Revision of the Systellopini (Coleoptera : Scarabaeidae : Melolonthinae)

The Systellopini, an Australian tribe of the Scarabaeidae : Melolonthinae, is revised. It now includes six genera and 19 valid species. The tribe is defined and keys are provided to genera and species. The new species described are: Sarothromerus aranda, Sa. niger, Sphyrocallus desertus, Sp. lloydi, Prochelyna houstoni, Enamillus septus, E. clevensis, and E. rectus. The following generic names are synonymized (synonym first): Tosotarsus Sharp and Atholerus Sharp = Prochelyna Erichson; Trichelasmus Sharp = Enamillus Sharp. The following specific names are synonymized (synonym first): Systellopus validus Sharp and Sy. ater Lea = Sy. obtusus Sharp; Atholerus obscurus Sharp = Prochelyna heterodoxa Burmeister. Previously described species are transferred to other genera as follows: Tosotarsus velutinus Sharp to Prochelyna; Trichelasmus basalis Blackburn to Enamillus; Sphyrocallus bicolor Blackburn to Enamillus; Trichelasmus pilicollis Sharp to Enamillus. Prochelyna rubella Schaufuss is transferred to the Liparetrini and synonymized with Pachygastra tasmanica Germar, and Metascelis flexilis Westwood is presumed not to be a systellopine. The other species recognized are Sarothromerus sharpi (Blackburn), Chilodiplus albertisi Sharp, Sphyrocallus brunneus Sharp, Enamillus mauricei Blackburn and E. striatus Sharp.

Spatial distribution and sequential sampling of Nysius spp. (Hemiptera: Lygaeidae) on sunflowers

Counts of adults of mixed populations of Nysius vinitor Bergroth and N. clevelandensis Evans on preflowering and postflowering sunflowers did not conform to the Poisson distribution because of overdispersion. Preflowering samples did not conform to the negative binomial model, but postflowering samples did with a common k of 3.78. Both sets of samples fitted significantly (P<0.01) Iwao's patchiness regression and Taylor's power law, but with significantly (P<0.01) different intercepts and slopes, respectively. Relationships to determine sample sizes for fixed levels of precision and fixed-precision-level stop lines are developed for both stages of crop development using Taylor's power law. Sequential decision plans based on Iwao's regression are developed for use in the management of Nysius spp. on preflowering and postflowering sunflowers.

Biology, Ecology and Control of Soldier Flies Inopus Spp (Diptera, Stratiomyidae) - a Review

The taxonomy and identification of the soldier flies, Inopus spp., their distribution, host plants, population biology and dynamics, and their chemical and cultural control are reviewed. Previous work has concentrated on I. rubriceps (Macquart), the most economically important species and a pest of sugar cane in Australia and pastures in New Zealand. Areas where further study is desirable include: the taxonomy and distribution of the genus; effects of host plants on development; processes involved in the inhibition of ratooning of sugar cane; detailed life-table studies on different host plants and different cultivars of sugar cane; damage and intervention thresholds and statistically based sampling plans for sugar cane; factors influencing pupation; the contribution of predation, parasitism and disease to mortality; control with insecticides other than organochlorines; the long-term need for insecticides; and control strategies other than insecticide treatments.

Development, Longevity and Fecundity of the False Wireworms Pterohelaeus-Darlingensis and Pterohelaeus-Alternatus (Coleoptera, Tenebrionidae) .4. Models for Larval and Pupal Development Under Fluctuating Temperatures

The usefulness of models derived from constant-temperature rearing in predicting development of larvae and pupae of Pterohelaeus darlingensis Carter and P, alternatus Pascoe under fluctuating temperature was determined. In general, these models underestimated development. The magnitude of the difference was proportional to the length of the development period and, by inference, negatively related to the temperatures experienced. New models were developed with data from individuals reared under fluctuating temperatures. The linear model gave better predictions of development under ambient conditions than did the curvilinear Stinner model for pupae of P. darlingensis, but both models gave similar predictions for larvae of both species. Development of P. alternatus pupae was still underestimated by both models. Substantial discrepancies between observed and expected development of individuals reared under a regimen incorporating a long period at low temperatures indicate that such a regimen is deleterious. Given the considerable variability in development rates between individuals, a stochastic model may predict development more accurately.

Development, Longevity and Fecundity of the False Wireworms Pterohelaeus Darlingensis and P. Alternatus (Coleoptera: Tenebrionidae) Iii. Interspecific Hybridization

In attempts to hybridise the polyphagous pests in Australia Pterohelaeus darlingensis Carter (D) and P. alternatus Pasc. (A), all eggs produced from matings of A females with D males were infertile. Some eggs in the D X A crosses hatched, producing adults similar to P. alternatus. These were fertile when backcrossed to each parent species and in F1 X F1 crosses. All the resultant F1 X A, A X F1 and F2 adults resembled P. alternatus, but like the F1 had different larval and pupal periods and, in A X F1, different larval and pupal survival from P. alternatus. In the D X F1 and F1 X D crosses, 68 and 74%, respectively, of the resultant adults appeared to be P. alternatus; the remainder were similar to P. darlingensis. There were differences in the development periods and survival rates from those of the parents.

Development, Longevity and Fecundity of the False Wireworms Pterohelaeus Darlingensis and P. Alternatus (Coleoptera: Tenebrionidae). Ii. Effect of Food Type

Pterohelaeus darlingensis Carter and P. alternatus Pasc. were reared under constant temperatures on 10 different foods in the laboratory in Australia. In P. darlingensis, wheat, barley and sorghum resulted in the shortest larval development periods, longest pupal periods and lowest pre-imaginal mortality. Egg-laying rates were highest on wheat, barley and maize and lowest on oats and soyabean. No females were produced after feeding on wheat straw, and no eggs were laid after feeding on linseed and turnip weed. Only wheat, barley, maize and sorghum (in descending order) allowed an increase in population. In P. alternatus, wheat, sorghum and barley resulted in the shortest pre-imaginal development with the least mortality. Egg-laying rates were highest on wheat, maize and sorghum and lowest on barley and oats. No eggs were laid by females fed on linseed. Wheat, sorghum, maize, sunflower, barley and soyabean allowed a positive population growth. These results are discussed in relation to control of the tenebrionids by crop rotation.

Gamasine Mites Associated With Australian Scarabaeid Beetles Ii. The Genus Cosmetolaelaps Womersley, Symbionts of Onthophagus Latreille

The following species of Cosmetolaelaps Womersley associated with Australian Onthophagus Latreille (Scarabaeidae : Scarabaeinae) are described and figured: microsetus, sp, nov., reticulatus, sp. nov., oligosetus, sp. nov., desecti, sp, nov., wallacei, sp, nov. and dolicacanthus (Canestrini). Species of Cosmetolaelaps show a degree of host-specificity at the species-group level: microsetus with the atrox group and O. consentaneus Harold; reticulatus with the atrox and declivis groups; oligosetus with the atrox group; desecti with the declivis group; wallacei with the auritus group; and dolicacanthus with the atrox and conspicuus groups and O. consentaneus.

Development, Longevity and Fecundity of the False Wireworms Pterohelaeus Darlingensis and P. Alternatus (Coleoptera: Tenebrionidae). I. Effect of Constant Temperature

All stages of P. darlingensis and P, alternatus were reared on wheat sprouts under constant temperatures ranging from 11.1 to 37.5�C. Eggs and larvae of both species developed between 15.8 and 33.1�C. Threshold temperatures for P. darlingensis and P. alternatus eggs were 13.8�C and 13.2�C respectively; 77.6 and 81.5 day-degrees above the threshold, respectively, were required for development. Larvae required 676.6 day-degrees above a threshold of 14.6�C, and 636.3 day-degrees above a threshold of 16.8�C, for development. Pupae developed between 11.1 and 37.5�C. P. darlingensis requiring 138.9 day-degrees above l3.6"C and P. alternatus 146.2 day-degrees above 13.4�C. Weekly fecundity and survival of adults were monitored; the optimal temperature for ovarian development was approximately 24.4�C. Survival of both sexes was similar at each temperature but longevity generally increased with decreasing temperatures. Parameters describing the biotic potential of both species were calculated; the capacities for increase were optimal at 28.6�C. The applicability of linear and curvilinear models for simulating development rates is discussed.

Gamasine Mites Associated With Australian Scarabaeid Beetles. I. The Genus Paradoxiphis Berlese, Symbionts of the Bolboceratini

The following species of Paradoxiphis Berlese associated with Australian Bolboceratini (Scarabaeidae : Geotrupinae) are described and figured: rotundus. sp. nov., dimorphus. sp. nov., black- bolbi, sp. nov., gigas, sp. nov., circumsetosus. sp. nov., longisetosus, sp. nov., bolboceras (Womersley), comb. nov., armstrongi (Womersley), comb. nov., longanalis, sp. nov., tenuibrachiatus Berlese, brevisetosus, sp. nov., womersleyi, sp. nov., matthewsi, sp. nov., brevisternum, sp. nov. and waterhousei. sp. nov. Schizolaelaps Womersley is synonymized under Paradoxiphis. Species of Paradoxihis are apparently host-specific at the generic level: rotundus and dimorphis with Bolboleaus Howden & Cooper; blackbolbi and gigas with Blackbolbus Howden & Cooper; circumsetosus, longisetosus, bolboceras and arnzstrongi with Elephastomus Macleay; longanalis, tenuibrachiatus and brevisetosus with Blackburnium Boucomont; and womersleyi, matthewsi, brevisternum and waterhousei with Bolborhachium Boucomont.