DNA fingerprint variation in some blackberry species (Rubus subg.Rubus,Rosaceae)

We have analysed samples from Sweden, Denmark, and Germany of six facultatively apomictic blackberry species to investigate the accordance between a taxonomy based on morphological characters on the one hand, and distribution of genetic variation estimated by DNA fingerprinting on the other hand. DNA fingerprint variation was found to be quite restricted in all species investigated. The first taxonomic group included three species related toRubus nessensis, two being characterized by one very widespread DNA fingerprint in all three countries and a few rare ones, whereas the third species differed between Sweden and Germany. The second taxonomic group included species related toR. gracilis. Two of these species exhibited very similar DNA fingerprints, whereas the third species deviated clearly. The utilization of DNA fingerprinting as a tool in taxonomy is discussed; most likely this method could become a useful complement to morphology, especially in plant groups with reduced levels of genetic recombination.     

Pachydellus hades (Halliday) (Acari: Pachylaelapidae), a European mite species described from Australia

Abstract  Pachydellus hades (Halliday) (Acari: Pachylaelapidae) was described from Jenolan Caves, NSW, Australia, and was thought to be an Australian endemic species. It is now known that this species is abundant in Slovakia and other parts of Europe, but its presence there was not recognised because it had been misidentified as other species. It appears likely that this species was introduced from Europe into Australia through human activities. The Australian type locality of this species gives a misleading impression of its native range.     

Host specificity ofAceria (Eriophyes) malherbe, [Acari: Eriophyidae], a biological control agent for the weed,Convolvulus arvensis [Convolvulaceae]

The host specificity of the gall mite,Aceria (Eriophyes) malherbe (Nalepa), from Greece was studied under quarantine conditions at Albany, California USA. Of the species, ecotypes, or strains tested, onlyConvolvulus andCalystegia spp. supported gall formation and mite reproduction. Although 2 of the native, North AmericanCalystegia species that served as laboratory hosts are threatened or endangered species,A. malherbe is considered safe for release in the USA as a biological control agent of the weed,Convolvulus arvensis (L.).      

Three new species from the subfamily Phyllocoptinae (Acari,Trombidiformes, Eriophyidae) in Iran

Three new eriophyid species (Phyllocoptinae), Shevtchenkella denticulata sp. n., Notallus pestehae sp. n. and Echinacrus ruthenicus sp. n., were described from Eryngium thyrsoideum Boiss. (Apiaceae), Pistacia vera L. (Anacardiaceae) and Lycium ruthenicum Murray (Solanaceae), respectively. All the three new species were collected from southwest of the East Azerbaijan province, Iran in 2011. It is the first record of an eriophyoid mite collected from E. thyrsoideum and L. ruthenicum and the first record of Notallus from Anacardiaceae plant family.     

Life cycle and host specificity ofEutinobothrus sp. (Col.: curculionidae) an agent for biological control ofSida acuta (malvaceae) in the northern territory,Australia

The biology of an undescribed weevil,Eutinobothrus sp., and its specificity toSida acuta, a serious weed in northern Australia, were studied in a quarantine facility in Australia. Sixty-eight plant species were screened and onlyS. acuta andS. rhombifolia could sustain populations ofEutinobothrus sp. Adults feed externally on the stems and oviposit in feeding scars. Larvae feed internally and pupate in the stem. Prepupae and pupae may aestivate in the stem and adults emerge with the onset of the wet season when new growth is evident.Eutinobothrus sp. was released in January, 1994 in the Northern Territory and has established.     

Strategies for the biological control of invasive willows (Salix spp.) in Australia

Abstract  Willows ( Salix spp.) are Weeds of National Significance in Australia where a large number of taxa are naturalised in temperate regions and can cause serious environmental degradation of riparian and wetland habitats. Several species are of economic or ornamental value and conflicts of interest could arise with planning their suppression. Biological control of six willow species ( S. alba L., S. cinerea L . , S. fragilis L., S. nigra Marshall, S. viminalis L., S . x  rubens Schrank) is under consideration in Australia using three approaches based on targeting different morphological structures. A rich phytophagous biota associated with Salix in their regions of origin indicate a range of organisms are available for development as biological control agents. Implementation strategies will depend on the host species targeted for biological control, their reproductive strategies, the level of control required to reduce environmental impacts and the level of conflict of interest associated with a biological control program.     

Predictions of summer diapause in the redlegged earth mite, Halotydeus destructor (Acari: Penthaleidae), in Australia

A prediction for the onset of a summer diapause in the eggs of the redlegged earth mite, Halotydeus destructor, was developed for Australia. In this species diapause eggs pass the summer in the cadavers of adult female mites. Adult female mites were collected for several weeks from pastures in spring at 18 sites in south-western Australia and dissected to determine the timing of the production of diapause eggs. Some sites were sampled for several years between 1990 and 1997. A model was developed to predict the time for onset of diapause. The week at which 90% of eggs were in diapause was predicted best by daylength (80.1% of the variability), then by duration of the long-term plant growing season (10.4%, of variability), leaving 9.5% due to other factors. A single chemical spray in spring 2 weeks before the production of 90% diapause eggs resulted in 99% fewer mites present in autumn 7-8 months later at three sites. The timing of the spring spray was the factor leading to successful control. This model was tested at 17 sites across the whole geographical distribution of the redlegged earth mite in Australia between 1998 and 2001. The observed week of 90% diapause was within 1 week of the predicted week on 81% of occasions, and 2 weeks earlier on 15% of occasions. A database was created for the predicted date of onset of 90% diapause for the whole distribution of the redlegged earth mite in southern Australia on a 10 km(2) grid. Australian farmers are using this for timing a spring spray to control mites in the following autumn.     

Direct and indirect species interactions influencing within-season dynamics of apple rust mite, Aculus schlechtendali (Acari: Eriophyidae)

We conducted a series of path analyses to determine which direct and indirect species interactions were most important in determining the within-season dynamics of apple rust mite (Aculus schlechtendali) (Eriophyidae) in a series of Nova Scotian (Canada) apple orchards. Typhlodromus pyri (Phytoseiidae) was usually more important than Zetzellia mali (Stigmaeidae) in the direct reduction of the apple rust mite population growth rate. When both predators contributed to lowering apple rust mite growth, T. pyri acted earlier in the season than did Z. mali. Predation by T. pyri was not affected by plant quality (nitrogen content or cultivar), but predation by Z. mali was enhanced by high nitrogen levels and was influenced by cultivar. There was little evidence of direct competition between Panonychus ulmi and apple rust mite in these orchards, possibly due to the low densities of P. ulmi. The indirect effects were generally smaller than the direct effects, but were occasionally important. Apparent competition between P. ulmi and apple rust mite was observed at times in some orchards, more often mediated by Z. mali than by T. pyri. Interference between the predator species was only occasionally strong enough to affect apple rust mite population dynamics.     

Factors affecting ambulatory dispersal in the predaceous mite Neoseiulus californicus (Acari: Phytoseiidae)

Experiments conducted in the laboratory showed that different biotic and abiotic factors affected the ambulatory dispersal behaviour of Neoseiulus californicus. The experimental set-up comprised dwarf alfalfa (Medicago polymorpha) infested or unifested by Tetranychus urticae. Temperatures were measured with thermocouples. Trials were performed at three temperatures, three prey densities, three light intensities, two relative humidities (RHs) and two vegetative states of alfalfa plants, turgid and withered. Deutonymphs were the most dispersive followed by young ovipositional females. High temperatures (35°C), high light intensities (40 000 lux) and drought-stressed alfalfa increased the dispersal of N. californicus. The availability of food in the environment and high moisture (80% RH) slowed down dispersion. The main factors which seem to elicit dispersal behaviour are the deprivation of food and high temperatures which result in an increase in the walking speed of the mite. In addition, other factors tested either increase or reduce the ambulatory dispersal of N. californicus. According to our results, individuals could move from ground cover into apple trees before spring. © Rapid Science Ltd. 1998     

Epiblema tetragonana and Epinotia ustulana (Lepidoptera: Tortricidae), two potential biological control agents for the invasive plant,Rubus ellipticus

Himalayan yellow raspberry, Rubus ellipticus is one of the world’s 100 worst invasive alien species. The plant has become a serious problematic weed in Hawaii, USA and is naturalized in many other countries. Screening of potential biological control agents is being conducted in its native region in Asia. In this paper, we report on the field distribution, abundance and host specificity of two leaf-rolling moth species, Epinotia ustulana and Epiblema tetragonana (Lepidoptera: Tortricidae). In larval non-choice tests both species only developed on plants in the genus Rubus. However, in adult choice oviposition tests, both leaf rollers showed a strong preference for R. ellipticus over other species. Furthermore, leaf-rolls by these two insects were only found on R. ellipticus in the field. These results indicate the moths have a narrow host range. Our field surveys also showed that both moth species are widely distributed in Yunnan Province, southeastern China, with up to 115 leaf rolls per plant, suggesting high levels of damage. These findings indicate that the two insects have considerable potential for biological control of R. ellipticus, though further host range tests should be conducted using more native plant species in Hawaii.     

Efficacy of indigenous predatory mites (Acari: Phytoseiidae) against the citrus rust mite Phyllocoptruta oleivora (Acari: Eriophyidae): augmentation and conservation biological control in Israeli citrus orchards

The citrus rust mite (CRM), Phyllocoptruta oleivora (Acari: Eriophyidae) is a cosmopolitan key pest of citrus, inflicting severe economic damage if not controlled. In Israel, CRM damages all citrus cultivars. International regulation and increasing control failures of CRM led growers to seek sustainable biological control solutions such as acarine biological control agents. Laboratory studies conducted in Israel have indicated that the indigenous predator species Amblyseius swirskii, Iphiseius degenerans, Typhlodromus athiasae and Euseius scutalis (all Acari: Phytoseiidae) can potentially control CRM. Our general objective in the present study was to bridge the gap of knowledge between laboratory studies and the lack of control efficacy of these species in commercial orchards. Predator augmentation in the field showed that although predator populations increased immediately following releases they later decreased and did not affect CRM populations. When A. swirskii augmentation was combined with a series of maize pollen applications, A. swirskii populations were enhanced substantially and continuously but again CRM populations were not affected. Growth chamber studies with CRM-infested seedlings, with or without a maize pollen supplement, indicated that pollen provisioning led to population increase of E. scutalis and A. swirskii but only E. scutalis significantly lowered CRM populations. Control with E. scutalis was confirmed in the field on CRM infested seedlings with pollen provisioned by adjacent flowering Rhodes grass. While experiments in mature citrus orchard showed that pollen supplement usually increased predator populations they also indicated that other factors such as intraguild interactions and pesticide treatments should be taken into account when devising CRM biological control programs.     

Allantus luctifer (Hymenoptera: Tenthredinidae), a candidate agent for the biological control of Rumex spp.

The dock plant (Rumex spp.) is one of the most problematic pasture weeds worldwide. Allantus luctifer was selected as a potential biological control agent for Rumex spp. Continuous rearing of A. luctifer was carried out from 2005 to 2006, and its general biology is presented in this report. The preliminary host specificity test showed a promising result for using A. luctifer to control Rumex spp.     

Host specificity testing,release and establishment of Urophora solstitialis (L.) (Diptera: Tephritidae), a potential biological control agent for Carduus nutans L., in Australia

The seed‐fly Urophora solstitialis was imported into Australia from southern France. Previous workers had shown that this seed‐fly limited its attack to selected members of the genus Carduus. Host specificity studies revealed that no native Australian plant tested from the family Asteraceae was a suitable host plant. Permission to release the fly was granted, and it was released in three regions of the New South Wales tablelands. The fly underwent a second generation at two of the release sites, and reasons for its failure to do so at the third are suggested. It has successfully established itself in all three regions, having completed a full seasonal cycle in the field.     

Parasitus bituberosus (Acari: Parasitidae), a possible agent for biological control ofHeteropeza pygmaea (Diptera: Cecidomyiidae) in mushroom compost

The prey items accepted byParasitus bituberosus Karg included all immature instars ofHeteropeza pygmaea Winnertz, first and second instars ofLycoriella solani together with its eggs, and compost nematodes and springtails. A preference was shown by deutonymphs for first-instarH. pygmaea, whereasHistiostoma feroniarum andPygmephorus sp. were not accepted. Adult mites, especially females, appeared to be even more voracious predators on first-instarH. pygmaea than were deutonymphs or protonymphs. The mite preventedH. pygmaea from reaching high populations in both laboratory-scale and small commercial-scale compost units; it also reduced populations of free-living nematodes in the latter. The distributions ofH. pygmaea and the mite throughout the compost in growing-bags were investigated and found to parallel each other. The mite was able to penetrate all parts of the compost. There was no evidence that it damagedAgaricus bisporus, and it was never found on harvested caps.     

Mite populations on grapevines in south-eastern Australia: Implications for biological control of grapevine mites (Acarina: Tenuipalpidae,Eriophyidae)

Pest and predatory mite populations were monitored over a 2 year period on grapevines in three viticultural regions of southern Australia (The Riverlands, Sunraysia and Murrumbidgee Irrigation Area [MIA]). The mite pestsBrevipalpus spp..Colomerus vitis (Pagenstecher) andCalepitrimerus vitis (Nalepa) occurred in each region with a predatory mite fauna which showed considerable interregional variation in incidence, abundance and composition. Nine species of Phytoseiidae, the dominant predatory mite family, were recorded inhabiting grapevines. In the Riverlands, mite populations were apparently suppressed by two phytoseiids (Typhlodromus doreenae Schicha,Amblyseius victoriensis (Womersley)) in vineyards on which no insecticide was used and on which sulphur and copper were used to control vine diseases. In Sunraysia and MIA, vineyards which generally had greater inputs of synthetic pesticides, particularly fungicides, five to eight phytoseiid species were recorded. However, they were less abundant and appeared to have less impact on mite (particularlyBrevipalpus spp.) populations. The population dynamics of pest and predatory mites on grapevines in southern Australia and implications for mite management based on biological control are discussed with respect to pesticide (particularly fungicide) inputs and phytoseiid biology/ecology.     

Host range of the European,rhizome-stem feeding scale Rhizaspidiotus donacis (Hemiptera: Diaspididae), a candidate biological control agent for giant reed,Arundo donax (Poales: Poaceae) in North America

The armored scale Rhizaspidiotus donacis (Leornardi) was evaluated as a potential biological control agent of the invasive reed grass Arundo donax in North America. No-choice tests, native range field surveys and non-target host exposures were used to determine the fundamental host range of the scale collected from Caloma, Spain and Perpignan, France. Thirty-five species, including two genotypes of A. donax and seven ecotypes of Phragmites australis, along with closely related grasses, economic grasses and habitat associates were tested. In quarantine no-choice testing using releases of 200 crawlers per plant, normal development of R. donacis was observed on A. donax and A. formosana, with very limited survival to the adult stage on Spartina alterniflora and Leptochloa spp. In follow-up studies using 1000 crawlers per plant, 10 live adult females were found on Leptochloa virgata, and one adult female on Spartina alterniflora, but average adult female abundance per plant was (2580%) 26-times lower on L. virgata and over (39,090%) 100-times lower on S. alterniflora than on A. donax. Field surveys were conducted at five locations in Spain and France at which A. donax infested with R. donacis, co-occurred with two non-target species of concern and R. donacis was only found on A. donax. Six-month field host exposures in Spain using potted Leptochloa plants entwined with heavily infested A. donax confirmed that R. donacis is specific to Arundo under field conditions. Based on our results, the scale R. donacis appears to be specific to the genus Arundo and is unlikely to harm native or cultivated plants in the Americas.     

Safety assessment and potential of Cecidophyes rouhollahi (Acari, Eriophyidae) for biological control of Galium spurium (Rubiaceae) in North America

Abstract:  Galium spurium L. (Rubiaceae), native to Europe, is an increasingly serious annual weed of cultivated crops in the prairie provinces of Canada. The gall mite Cecidophyes rouhollahi Craemer (Acari, Eriophyidae), originally found on the related plant species Galium aparine L. in southern France, was evaluated as a potential biological control agent for G. spurium . In greenhouse tests, C. rouhollahi caused severe stunting and complete prevention of seed production by G. spurium . Host specificity tests showed that C. rouhollahi developed only on three closely related annual Galium species in the Kolgyda section. No native North American Galium species were attacked, with the exception of G. aparine . A review of available information on G. aparine suggests that it is probably an introduced species in North America. It has been reported that a related gall mite attacking G. aparine might be associated with a plant virus. A series of tests on a greenhouse colony of G. spurium infested with C. rouhollahi showed no evidence of viral infection. On the basis of these results, C. rouhollahi has been approved for field release against G. spurium in Canada.