Studies on the rustMaravalia cryptostegiae,a potential biological control agent of rubber-vine weed (Cryptostegia grandiflora,Asclepiadaceae: Periplocoideae) in Australia,I: Life-cycle

Three spore types are described forMaravalia cryptostegiae: hemileioid urediniospores; thin-walled, hyaline, ellipsoidal, non-resting teliospores and ovoid to lacrimoid basidiospores. Field surveys in the Madagascan native range of rubber-vine failed to confirm the existence of spermogonia and morphologically distinct aecia within the life-cycle. Greenhouse inoculations with basidiospores were unsuccessful. Cytological studies revealed that rubber-vine rust has a similar nuclear cycle to that reported for coffee leaf rust,Hemileia vastatrix. The working hypothesis is proposed thatMaravalia cryptostegiae is a primitive, autoecious tropical forest rust with only a short or partially expanded life-cycle represented by two teliospore forms. The predominant, functional form is uredinioid with a novel nuclear cycle, in which there is a delayed meiotic division (the Kamat phenomenon). The non-dispersed form appears to be vestigial or non-functional since it germinates to produce a metabasidium with genetically variable and unstable basidiospores. The relationships and evolutionary significance of the generaMaravalia andHemileia are discussed.     

The rust mycobiota of southern Africa: Species richness, composition, and affinities

The rust mycobiota (Uredinales, Basidiomycota) of southern Africa (Botswana, Namibia, and South Africa) is analysed with regard to species richness, generic composition, and similarities to the rust mycobiotas of the remaining African continent and other regions of the world. Southern Africa is home to about 546 rust species: ca 522 species have been reported from South Africa, 73 from Namibia, and less than ten from Botswana. Thirty-two species were considered to be exotics. Two hundred and twenty-five of the species are restricted to southern Africa, suggesting an endemism rate of ca 44 %. At present, the rust fungus:host ratio is 1:38.5, which is much lower than expected from other regions of the world. This low ratio may partly be due to under-exploration of the area, but the results presented here indicate that a natural paucity of rust fungi on certain, especially species-rich plant taxa centred in southern Africa and possibly environmental factors are more important reasons. The predominant genera are Puccinia and Uromyces accounting for ca 59 % of the rust species. The genera Hemileia, Phakopsora and especially Ravenelia, centred in tropical regions, are well represented and sum up to 8 % of the species. Members of Melampsoraceae and Phragmidiaceae, common in temperate regions of the Northern Hemisphere, are scarce. Most of the other 28 recorded teleomorph genera are only represented by three or less species. In an African context, most species are shared with central and east Africa (almost 16 %). Only a few species are disjunct between southern and West Africa or Madagascar. Ca 10 % of the species are shared only with other parts of the paleotropics, especially the Indian subcontinent. Disjunctions of native species with the New World, Australia/New Zealand, or Europe are rare.     

Biology and host plant range of the soft scale,Steatococcus new species [Hem.: Margarodidae] for the biological control of the weedCryptostegia grandiflora [Asclepiadaceae]

The soft scale,Steatococcus new species, occurs onCryptostegia grandiflora R. Br. in Madagascar. Studies on its biology and host plant range showed colonies could survive for up to 6 months on some genera in theApocynaceae and indefinitely on many genera in the familyAsclepiadaceae. The species was therefore rejected as a biological control agent forC. grandiflora, a serious weed in northern Queensland, Australia.      

Molecular evidence that fireweed (Senecio madagascariensis, Asteraceae) is of South African origin

ITS1 sequence data was obtained for fireweed (Senecio madagascariensis) andS. lautus from Australia,S. madagascariensis andS. inaequidens from South Africa andS. madagascariensis from Madagascar. Despite the low level of variation (0.0–3.4%), these data further resolve the controversy concerning the identity and origin of fireweed. They confirm that fireweed is part of the South AfricanS. madagascariensis/S. inaequidens complex, and indicate that the infestation in Australia originated from South Africa as opposed to Madagascar. This will facilitate a resumption of biological control efforts in Australia and will direct surveys for control agents to South Africa.     

Developmental Host-Specificity of Mozena obtusa (Heteroptera: Coreidae), a Potential Biocontrol Agent for Prosopis Species (Mesquite) in Australia

Mozena obtusa Uhler (Heteroptera: Coreidae) was examined in quarantine for its potential as a biological control agent of Prosopis species (mesquite) in Australia. Trials were conducted on 16 nontarget plant species to estimate its developmental host range. Complete development occurred on all Prosopis species that have become naturalized in Australia as well as on four Australian native species (Neptunia species and Paraserianthes lophantha), although reproductive diapause prevented assessment of subsequent fecundity. Development through the first feeding nymphal instar also occurred on other plant species representing two subfamilies. Nymphal performance was highly variable on both target and nontarget species, possibly because variation in plant nitrogen composition affected plant quality. The correlation between environment, plant nitrogen, and plant quality is likely to be sufficiently strong to determine whether a plant species can support development. Plant quality should therefore be considered when predicting the field host range of M. obtusa and of sap-sucking coreids generally. Nonetheless, our preliminary results suggest that M. obtusa may not be sufficiently specific for release in Australia, although insufficient understanding of its oviposition behavior in the field and the effect of plant quality on development means that its rejection would be premature.     

Morphological and molecular characterisation of Puccinia lagenophorae, now present in central North America

In June 2004, a rust fungus not previously reported for Oklahoma was found occurring naturally on the weed, common groundsel, Senecio vulgaris, in pots in a commercial container nursery in northeastern Oklahoma. Host symptoms and morphology of teliospores and aeciospores of the fungus were consistent with those of Puccinia lagenophorae, a recent introduction into North America that has, as yet, been reported only on the East and West Coasts of the USA. This is the first report of the rust in central regions of North America. The rust is believed to be native to Australia and New Zealand and subsequently reported in most continents on numerous species and genera of the Asteraceae. Some authors in Europe consider the rust on Bellis as different from the one on Senecio, naming it Puccinia distincta. Our ITS1‐5.8S‐ITS2 ribosomal DNA sequence data, however, show homology with P. distincta sequences from Europe, indicating there is only one morphologically‐variable polyphagous species. Presumably, the rust was introduced into Oklahoma on infected plants from the West Coast of the USA, the source of most plant material in the commercial nursery where it was found. The rust is potentially important on several ornamental Asteraceae in North America as it has become in Europe, where it spreads rapidly throughout that continent following its introduction there in the early 1960s.     

Initial screening of the stem-boring weevil Osphilia tenuipes, a candidate agent for the biological control of Bryophyllum delagoense in Australia

A stem-boring weevil, Osphilia tenuipes (Fairmaire) (Coleoptera: Curculionidae), from Madagascar, was screened in South Africa to determine its potential as a biological control agent for Bryophyllumdelagoense (Ecklon & Zeyher) Schinz(Crassulaceae) in Australia. Favourableattributes of the weevil include ease ofculturing, multiple generations per year, andhigh levels of damage inflicted on B. delagoense under laboratory conditions. Despite indications that O. tenuipes hasa narrow field host range, no-choice andmultiple-choice trials in quarantine revealedthat it could oviposit and develop to adulthoodon seven non-target species in the familyCrassulaceae, without an obvious loss offitness on four of those species. Despitethese results, O. tenuipes is consideredto have potential for release against B. delagoense in Australia because the continenthas very few native Crassulaceae which couldpotentially serve as alternative hosts in thefield.     

Novelties in Adenia (Passifloraceae): Four new species, a new combination, a vegetative key, and diagnostic characters for known Madagascan species

Four new species and one new combination ofAdenia are presented, along with a vegetative key and diagnostic characters of the Madagascan species. Additional notes are provided about unusual specimens and field observations.Adenia kigogoensis from Tanzania is shown to be distinct fromA. stenodactyla (its putative closest relative) andA. digitata based on anther connation and other floral traits. The remaining new taxa are from Madagascar.Adenia litoralis has been observed from one coastal locality in northern Madagascar. It is distinctive in fruit size and leaf form.Adenia metamorpha is the only Madagascan taxon with a narrow cylindrical trunk and large napiform tuber; it is also known from only one locality in Madagascar in the Ankarana Reserve.Adenia mcdadiana is a robust liana with highly reduced glands and leaves that appear to be neotenic compared to its closest putative relative,A. sphaerocarpa. Finally, the position ofA. stylosa has been clarified. This species was once treated asA. firingalavensis var.stylosa, and prior to that asA. epigea var.stylosa, but molecular and morphological data suggest it is separate from these species.     

Phylogenetic relationships and biogeography of Ptilophora (Gelidiales,Rhodophyta) with descriptions of P. aureolusa,P. malagasya,and P. spongiophila from Madagascar

The genus Ptilophora currently includes 16 species occurring mostly in subtidal habitats of the Indo‐Pacific Ocean, but its global diversity and biogeography are poorly understood. We analyzed mitochondrial cox1, plastid rbcL and plastid psbA sequences from specimens collected in southern Madagascar during the 2010 Atimo Vatae expedition and studied their morphologies. Both morphological and molecular data sets demonstrated the presence of five species in southern Madagascar: Ptilophora hildebrandtii, P. pterocladioides, and three new species described here, P. aureolusa, P. malagasya, and P. spongiophila. Ptilophora aureolusa is distinguished by its compound pinnae with uniformly spaced pinnules. Ptilophora malagasya has an indistinct midrib and irregularly spaced pinnules. Ptilophora spongiophila, heavily coated with sponges, has cylindrical to flattened main axes, lateral and surface proliferations, and spatulate tetrasporangial sori. The species of Ptilophora found in Madagascar are endemic, except P. hildebrandtii, which also occurs in eastern Africa. Ptilophora comprises four phylogenetic groups that map to eastern Australia, Japan, western Australia/Southeast Asia/Madagascar/eastern Africa, and Madagascar/eastern Africa/Aegean Sea. Biogeographical analysis revealed that the ancestor of Ptilophora originated in Australia, but most of the species radiated from Madagascar.     

Uromyces vankyorum sp. nov. and Uromyces atriplicis, putative vicariant rust species of Patagonian and Australian semi-desert biomes

Uromyces vankyorum (Basidiomycota, Uredinales) growing on Atriplex lampa in the cool Patagonian dwarf shrub semi-desert is described as a new species and a new member of the Argentinean rust mycota. The fungus is morphologically similar to Uromyces atriplicis on Atriplex vesicaria from halophytic shrublands of South Australia. U. atriplicis seems to be derived from U. vankyorum as indicated by its shortened life cycle lacking the urediniospore stage. The species are interpreted as trans-pacific vicariants and represent one of the rare examples for the austral South American-Australasian element among rust fungi. The disjunct distribution of rust fungi between austral South America, Australia and New Zealand is reviewed and discussed. Available data suggest migration of rust fungi along Gondwanan land bridges rather than long-distance dispersal of spores by air currents. Part 198 of the series “Studies in Heterobasidiomycetous Fungi” of the Botanical Institute, University of Tübingen     

Biological control of Ziziphus mauritiana (Rhamnaceae): feasibility,prospective agents and research gaps

The tropical fruit tree, Ziziphus mauritiana (Rhamnaceae), a native of the Indian subcontinent, is a pasture and environmental weed in northern Australia and Fiji. In their native range, Ziziphus spp., including commercially cultivated Z. mauritiana and Z. jujuba, are subjected to a wide range of pests and diseases. The feasibility of classical biological control of this weed has not been explored to date. Effective biological control could reduce plant vigour and seed output, thereby limiting the spread of Z. mauritiana in Australia. Two Ziziphus species are native to Australia, hence, any prospective biological control agent should be specific to Z. mauritiana. Opportunistic field surveys and literature searches identified 133 species of phytophagous insects, 9 species of phytophagous mites and 12 plant pathogens on Ziziphus spp. Host records suggest the following are possibly specific to Z. mauritiana and hence are prospective biological control agents in Australia: the seed‐feeding weevil Aubeus himalayanus; the leaf‐feeding gracillariid moth Phyllonorycter iochrysis; the leaf‐mining chrysomelid beetle Platypria erinaceus; the leaf‐folding crambid moth Synclera univocalis; the leaf‐galling midge Phyllodiplosis jujubae; and the gall‐mites Aceria cernuus and Larvacarus transitans. Host range of the rust Phakopsora zizyphi‐vulgaris includes many Ziziphus species, including the native Z. oenoplia and hence would not be a suitable biological control agent in Australia. The powdery mildew Pseudoidium ziziphi, with a host range restricted to Ziziphus species, has not been reported on Z. oenoplia. All available information on the pests and diseases of Z. mauritiana are from cultivated varieties. Hence, future surveys should focus on wild Z. mauritiana in the Indian subcontinent in areas that are climatically similar to the regions of northern Australia, where it is currently most abundant.     

An Evaluation of the Rust FungusGymnoconia nitensas a Potential Biological Control Agent for AlienRubusSpecies in Hawaii

The rust fungusGymnoconia nitensinfects blackberry (Rubus argutus) systemically in regions of the continental United States, producing bright yellow–orange masses of spores on newly developing floricanes during springtime. In tests to determine the suitability of this rust as a biological control agent forR. penetransin Hawaii, a species now thought to be conspecific withR. argutus,rooted cuttings of the Hawaiian plants were grown at North Carolina State University, inoculated, and observed. Other introduced weedyRubusspp. in Hawaii, includingR. ellipticus, R. rosifolius,andR. glaucus,as well as the two endemic speciesR. hawaiensisandR. macraei,also were inoculated. No species ofRubusare of commercial importance in Hawaii, but the protection of the native species, of whichR. macraeiis rare, was of utmost concern. The native Hawaiian species did not survive well in North Carolina in this study, however. Later availability of a plant pathogen containment laboratory in Hawaii enabled similar tests to be conducted at that facility. In addition to the above species,R. spectabilis(salmonberry), a species native to the Pacific Northwest with which the HawaiianRubusspp. are thought to share a common ancestor, was inoculated in Hawaii. Infection withG. nitensunder natural field conditions becomes apparent only when sporulation occurs on floricanes the second year following infection. However, experimental inoculation led to early responses of chlorotic leaf flecking and puckering, leaf and stem contortion, and stem gall formation, indicating the sensitivity ofR. penetrans(=R. argutus),R. hawaiensis,andR. macraeito this rust. Apparent systemic infection also resulted in sporulation on one plant ofR. macraei.Ability to attack the endemic species suggests thatG. nitenswould not be suitable for release in Hawaii as a biological control agent, at least on the islands with populations of the native species.     

Phylogeny and taxonomy of the Asian grapevine leaf rust fungus, <Emphasis Type="Italic">Phakopsora euvitis</Emphasis>, and its allies (Uredinales)

Heteroecious Phakopsora euvitis, P. vitis, and P. ampelopsidis, autoecious P. meliosmae, and an unconnected Aecidium on Meliosma are closely allied. A total of 45 collections representing the five rust fungi from Japan, Australia, and East Timor were subjected to molecular phylogenetic analyses: the D1/D2 region of nuclear large subunit rDNA and nuclear small subunit internal transcribed spacer 2 (ITS2) region including 5.8S rDNA were analyzed. Tree topologies generated from parsimony and distance methods of the D1/D2 and ITS2 sequences were similar. The 45 collections (44 for ITS2 and 33 for D1/D2, with 32 common for both analyses) are grouped into seven clades: P. ampelopsidis, P. vitis, unconnected Aecidium, P. euvitis from Japan, P. euvitis from Australia and East Timor, P. meliosmae on M. myriantha, and P. meliosmae on M. tenuis. The results confirm the phylogenetic distinctness of P. euvitis, P. ampelopsidis, and P. vitis distributed in Japan. A grapevine leaf rust fungus in Australia and East Timor has genetically diverged from P. euvitis in Japan. The unconnected Aecidium is highly likely to be an aecial anamorph of a Phakopsora fungus. Autoecious Phakopsora fungi on M. meliosmae and M. tenuis need further host-specificity and morphological studies to confirm their taxonomic status.     

Species boundaries in Malagasy snakes of the genus Madagascarophis (Serpentes: Colubridae sensu lato) assessed by nuclear and mitochondrial markers

We studied mitochondrial divergence in 27 individuals of colubrid snakes of the genus Madagascarophis Mertens from most of its distribution area in Madagascar. Combined analyses of 16S rRNA and cytochrome b sequences identified six major clades which only partly agreed with previously proposed classifications. Analysis of nuclear DNA sequences of the c-mos gene as well as of ISSR fingerprints revealed consistent differences only among three clades which we consider as distinct species: a widespread Madagascarophis colubrinus (Schlegel), with M. citrinus (Boettger) as a junior synonym, a southern M. meridionalis Domergue, and a presumably undescribed species from the extreme north of Madagascar. The species M. ocellatus Domergue was not available for our study. Within M. colubrinus there are two populations from the north-west, each showing two divergent haplotypes with pairwise divergences of up to 5.2% in the cytochrome b gene. Maximum divergence in this gene within M. colubrinus was 7.1%. These high values emphasise that caution needs to be applied before genetic distance values are used for species delimitation. Phylogeographically, most of the genetic variation in M. colubrinus is found in northern Madagascar, indicating that the species might have originated in this region. Later one haplotype clade colonised western and eastern Madagascar, with a putative secondary introgression into north-western populations.     

Molecular evidence for species level divergence in African Nile Crocodiles Crocodylus niloticus (Laurenti, 1786)

Relationships of the newly discovered dwarf crocodiles from Mauritania were inferred from mitochondrial 12S sequences. Specimens from 13 different Crocodylus niloticus populations (from East Africa, West Africa and Madagascar) were compared. Additional representatives of the genus Crocodylus (one from Africa and one from Australia), the African genus Osteolaemus and the South American alligatorid Paleosuchus palpebrosus (as outgroup) were included in the analysis. Maximum-likelihood and Bayesian analyses yielded relationships that were strikingly different from currently prevailing phylogenetic hypotheses. Both analyses consistently revealed two groups, one consisting of the monophyletic West- and Central African populations and the other of a paraphyletic group containing the East African and Madagascan populations. High genetic divergence between those groups indicates separation on the species level. Furthermore ‘C’ cataphractus is clearly shown not to be a member of the genus Crocodylus. The resulting nomenclatural changes are discussed. To cite this article: A. Schmitz et al., C. R. Palevol 2 (2003).     

Host specificity, establishment and dispersal of the gorse thrips, Sericothrips staphylinus Haliday (Thysanoptera: Thripidae), a biological control agent for gorse, Ulex europaeus L. (Fabaceae), in Australia

Sericothrips staphylinus was released as a biological control agent for Ulex europaeus in New Zealand and Hawaii following tests on ca. 80 plant species which showed it was narrowly oligophagous. To determine the suitability of S. staphylinus for release in Australia, further host specificity tests were conducted on 38 species and cultivars of Australian plants. These tests confirmed that S. staphylinus would feed only on U. europaeus in Australia and, following formal approval, was released in Tasmania during January 2001. To develop an optimal release strategy for S. staphylinus under Australian conditions, a field trial based on an earlier New Zealand study was conducted by replicating releases of 10, 30, 90, 270 and 810 adults. Results showed that population growth, reproduction rate and the number of S. staphylinus recovered 14 months after release can be non-linear functions of release size and establishment could be achieved with as few as 10 thrips. As S. staphylinus is easily cultured ca. 250 thrips were chosen as the minimum number for release because, based on a negative binomial model, this release size produced close to the maximum population growth. Surveys in early 2007 recovered S. staphylinus from 80% of 30 sites in Tasmania, the post release period ranging from 1 to 6 years. However, densities were low (<1 thrips/cm of tip growth) with no evidence of visible plant damage. The maximum dispersal range was 180–250 m after 38 months. At all the other sites, dispersal was estimated at less than 120 m. It is possible that S. staphylinus populations are still in the lag phase of their establishment before starting to increase rapidly and disperse. However, the survey results support a recent Tasmanian study which indicated that S. staphylinus is a sedentary, latent species characterised by steady densities and low levels of damage to its host plant. Its efficacy as a biological control agent on gorse may be restricted primarily by ‘bottom up’ effects of plant quality limiting its rate of natural increase and an inability of the thrips to reach large, damaging populations under field conditions.     

A leaf feeding moth,Euclasta whalleyi [Lep.: Pyralidae] for the biological control ofCryptostegia grandiflora [Asclepiadaceae] in Queensland,Australia

In Madagascar, the leaf feeding Pyralid,Euclasta whalleyi Popescu-Gorj & Constantinescu, occurs onCryptostegia grandiflora R. Br. and other genera in the subfamilyPeriplocoideae of the familyAsclepiadaceae. Studies on its biology and host plant specificity have shown it is restricted to this subfamily. The Australian native,Gymnanthera nitida R. Br., also belongs to this sub-family and is host to an Australian native moth,Euclasta maceratalis Lederer. Despite the likelihood ofE. whalleyi feeding onG. nitida and competing withE. maceratalis, the moth was approved for release in Australia in October 1987. During 1988 over 22,000 larvae were released; field establishment is not yet proven.      

Biogeography of Dwarf Lemurs: Genetic Evidence for Unexpected Patterns in Southeastern Madagascar

Seven species of dwarf lemurs (Cheirogaleus spp.) are currently recognized after a recent revision of the genus. During a field study in southeastern Madagascar, we observed 3 distinct morphotypes of Cheirogaleus resembling Cheirogaleus medius, C. major and C. crossleyi. In particular, for Cheirogaleus crossleyi southeastern Madagascar was far away from the known distribution range of the species when referring to the recent revision of the genus. In order to clarify the taxonomic status of the 3 morphotypes, we compared field samples from southeastern Madagascar to museum specimens from several locations in Madagascar and to field samples from Kirindy/CFPF, western Madagascar by genetic analyses using the mitochondrial cytochrome b gene. Genetic data yield strong support for 2 of the 3 morphotypes to represent Cheirogaleus medius and C. major. The third morphotype is genetically closely related to Cheirogaleus crossleyi, albeit more distantly than the other 2 morphotypes to the respective reference samples. The genetic distance is related to a considerable geographic distance between the location of our field study and the origin of the respective reference specimen, because Cheirogaleus crossleyi had been reported only from northern Madagascar. Our field observations indicate an isolated population in southeastern Madagascar. We propose to identify them as Cheirogaleus crossleyi and discuss the population genetic and biogeographic considerations supporting this conclusion.     

Ornithodoros porcinus ticks, bushpigs, and African swine fever in Madagascar

African swine fever (ASF) has recently made its appearance in Madagascar. Ticks of the Ornithodoros moubata group, considered to be O. porcinus Walton, 1962 were formerly known to occur in western Madagascar, but seem to have disappeared from that region. However, three new sites where they occur were found in the humid and cool central highlands of Anatananarivo province. These ticks are known to be efficient reservoirs and vectors of ASF and constitute a considerable complication to the control of the disease. The authors also discuss another potentially complicating factor, the presence of a species of African bushpig, Potamochoerus larvatus.     

Plant/pathogen interactions observed during host range testing of the rust fungus Uromyces pencanus,a classical biological control agent for Chilean needle grass (Nassella neesiana) in Australia and New Zealand

Nassella neesiana (Chilean needle grass) is a South American grass species that is a serious weed in Australia and New Zealand. The rust fungus Uromyces pencanus is a promising biocontrol agent that could be used to control the weed in both countries. Extensive host range testing has been conducted to explore the specificity of the rust. In this paper we discuss the different degrees of invasion by the rust of the tissues of target and non-target species; the plant defences elicited by such invasion at the cellular level; and their relevance to the biological control of Chilean needle grass.