Nachweis der Australischen Schabe (Periplaneta australasiae [Fabricius, 1775]) in Sachsen-Anhalt

The Australian cockroach (Periplaneta australasiae [Fabricius, 1775]) is a roach species that is scarcely found in Germany. On the territory of Saxony-Anhalt it has only been detected twice, these observations dating back more than 60 years. In early 2001, a mass appearance of the Australian cockroach was recorded in a greenhouse of the Magdeburg Zoological Gardens. The author is not aware of any other current appearance of the Australian cockroach in the land of Saxony-Anhalt.     

Nachweis der Braynbandschabe (Supella longipalpa [Fabricius, 1798]) in Sachsen-Anhalt

Evidence of the brown-banded cockroach (Supella longipalpa [Fabricius, 1798]) in Saxony-Anhalt In the past, evidence of the brown-banded cockroach in the Land of Saxony-Anhalt was based on reports furnished by pest control businesses to the extent that brown-banded cockroaches had been traced on the premises of two Magdeburg companies in 1985. A specimen of brown-banded cockroach was recently detected in the Land of Saxony-Anhalt (March 2000). The roach was found in the office of a smallsized business in the town of Wolmirstedt north of Magde burg. The route along which the pest had entered the premises, or been brought in, could not be elucidated.      

Nachweis der Braynbandschabe (Supella longipalpa [Fabricius, 1798]) in Sachsen-Anhalt

Evidence of the brown-banded cockroach (Supella longipalpa [Fabricius, 1798]) in Saxony-Anhalt In the past, evidence of the brown-banded cockroach in the Land of Saxony-Anhalt was based on reports furnished by pest control businesses to the extent that brown-banded cockroaches had been traced on the premises of two Magdeburg companies in 1985. A specimen of brown-banded cockroach was recently detected in the Land of Saxony-Anhalt (March 2000). The roach was found in the office of a smallsized business in the town of Wolmirstedt north of Magde burg. The route along which the pest had entered the premises, or been brought in, could not be elucidated.     

über das Auftreten der Lapplandschabe (Ectobius lapponicus [Linné 1758]) in Geb?uden

In Germany, the dusky cockroach (Ectobius lapponicus [Linné, 1758]) lives in woodland. Dwelling of these insects which are not considered a pest, in buildings is an extremely rare observation. In early summer of 2000, several areas of a forest hospital were found to be infested withEctobius lapponicus. In contrast, the German cockroach (Blattella germanica [Linné, 1767]) had not been found in that, hospital for years. In the light of the literature available, an attempt is made to provide a survey of infestation of buildings with the dusky cockroach.      

über das Auftreten der Lapplandschabe (Ectobius lapponicus [Linné 1758]) in Geb?uden

In Germany, the dusky cockroach (Ectobius lapponicus [Linné, 1758]) lives in woodland. Dwelling of these insects which are not considered a pest, in buildings is an extremely rare observation. In early summer of 2000, several areas of a forest hospital were found to be infested withEctobius lapponicus. In contrast, the German cockroach (Blattella germanica [Linné, 1767]) had not been found in that, hospital for years. In the light of the literature available, an attempt is made to provide a survey of infestation of buildings with the dusky cockroach.     

Toxicity and electrophysiological effects of Spilanthes amella Murr. extracts on Periplaneta americana L.

The potential insecticidal activity of Spilanthes acmella Murr. (Compositae) extracts was assessed in this study. The extracts were shown to be toxic against adults of American cockroach, Periplaneta americana L. The active component in S. acmella extract was isolated and identified as N-isobutyl-2,6,8-decatrienamide (spilanthol). The results from topical application of spilanthol show that it has a high acute toxicity and spilanthol was the most potent compound when compared to three conventional insecticides. The potency was found to be 1.3, 2.6 and 3.8 times more toxic than carbaryl, bioresmethrin and lindane, respectively. Electrophysiological studies indicated immediate hyperexcitation followed by complete inhibition of the cockroach cercal nerve activity.     

The Knockdown Resistance (kdr) Mutation in Pyrethroid-Resistant German Cockroaches

A point mutation in thepara-homologous sodium channel gene has been shown to be associated with knockdown resistance (kdr) in several insect species including the German cockroach. In this study, we analyzed the genomic organization of the region where thekdrmutation resides and then performed polymerase chain reaction (PCR) and sequencing using genomic DNA as the template to detectkdrmutation in 24 pyrethroid-resistant German cockroach strains, most of which have been collected recently from the field. Thekdrmutation, G to C at nt 2979 resulting in a leucine to phenylalanine amino acid substitution, was detected in 20 strains including 2 strains from overseas (China and Germany). Our results clearly indicate that thekdrmutation is widespread in German cockroach populations. However, the super-kdrmutation detected in super-kdrhouse flies was not found in any of the 4 strains that showed higher levels of knockdown resistance. Little correlation was observed between the presence of thekdrmutation and the level of knockdown resistance, suggesting the existence of multiple resistance mechanisms in many of these strains.     

Variation in potential effector genes distinguishing Australian and non‐Australian isolates of the cotton wilt pathogen Fusarium oxysporum f.sp. vasinfectum

This study identified genes that distinguish Australian Fusarium oxysporum f.sp. vasinfectum (Fov) isolates from related co‐localized non‐pathogenic F. oxysporum isolates and from non‐Australian Fov isolates. One gene is a homologue of the F. oxysporum f.sp. lycopersici (Fol) effector gene SIX6, encoding a 215‐residue cysteine‐rich secreted protein. The Six6 proteins from Fol and Fov contained eight conserved cysteine residues, five of which occurred in the highly diverged 48‐amino‐acid region where FovSix6 differs from FolSix6 at 32 residues. Two other potential effector genes, PEP1 and PEP2, were identified in a cDNA library of Fov genes expressed during infection of cotton. The presence of FovSIX6 and other differences in DNA fingerprints clearly distinguished Australian Fov isolates from non‐Australian Fov isolates and these differences further support the hypothesis based on earlier phylogenetic analysis that Australian Fov is different from Fov in other cotton‐growing areas. A specific diagnostic for Fov based on FovSIX6 is described.     

Fusarium oxysporum f. sp. canariensis: evidence for horizontal gene transfer of putative pathogenicity genes

Fusarium wilt is a serious disease of the date palm Phoenix canariensis, caused by Fusarium oxysporum f. sp. canariensis (Foc). A previous study that characterized and compared the genetic diversity of the Australian Foc population with international strains suggested that the Australian population may have had an independent evolutionary origin. The current study compared the species phylogeny of the Australian and international populations and determined that Foc is not monophyletic, separating into three supported lineages across the two phylogenetic species of the Fusarium oxysporum species complex. This confirms an independent evolutionary origin for Foc in Australia. However, phylogenetic analysis of the putative pathogenicity genes Secreted In Xylem (SIX) did not reveal any separation of the Australian and international Foc strains. Furthermore, there was very low SIX sequence diversity within Foc. Horizontal gene transfer is argued to be the most parsimonious explanation for the incongruence between the species and SIX gene phylogenies.     

Actions of pyrethroid insecticides on insect axonal sodium channels

The actions of pyrethroid insecticides were tested on isolated giant axons of the cockroach Periplaneta americana, using oil-gap, single-fibre recording techniques. Current-clamp and voltage-clamp experiments were used to determine the actions of pyrethroids on axonal membrane potentials and ionic currents. Treatment with deltamethrin at micromolar concentrations caused gradual depolarisation of the axon accompanied by a reduction in amplitude of the action potential. This depolarisation was enhanced by an increase in stimulation frequency. Other synthetic pyrethroids: 3,4,5,6-tetrahydrophthalimidomethyl (1RS)-cis-3-[(RS)-2,2-dimethylcyclopropyl]-2,2-dimethylcyclopropanecarboxylate, biopermethrin and its (1S)-enantiomer, (1R)-tetramethrin, S-bioallethrin, bioresmethrin and its (1S)-enantiomer, cismethrin, and 5-benzyl-3-furylmethyl (E)-(1R)-cis-2,2-dimethyl-3-(2-oxothiolan-3-ylidenemethyl)cyclopropanecarboxylate (RU-15525, ‘Kadethrin’) were investigated. The (1S)-enantiomers were inactive, but all the other pyrethroids tested, apart from deltamethrin, induced prolonged negative (depolarising) after-potentials. All the treatments with the active pyrethroids resulted in the appearance of a voltage and time-dependent ‘maintained’ sodium conductance. The duration of this ‘slow’ conductance varied considerably depending on the pyrethroid under test. Clearly, the effectiveness of pyrethroids on whole insects is not determined only by the degree to which they directly modify the properties of sodium channels. Nevertheless, voltage-clamp experiments on isolated axons readily permit direct comparison of the actions of different pyrethroids on the sodium channels of insect neurones.     

Development of strategies for monitoring indoxacarb and gel bait susceptibility in the German cockroach (Blattodea: Blattellidae)

BACKGROUND: Advion^® cockroach gel bait (6 g kg^?1 indoxacarb) is in widespread use for Blattella germanica (L.) control in the United States. However, baseline susceptibility levels to indoxacarb in German cockroach field populations are not known. Hence, this research sought to develop monitoring strategies to estimate the susceptibility of German cockroach populations to indoxacarb. RESULTS: Four bioassays were evaluated: topical lethal dose (LD), formulated gel bait lethal time (LT), vial lethal concentration (LC) and gel bait matrix LD. Of these methods, the vial LC and gel bait matrix LD bioassays were the most economical and relevant assessment strategies. For indoxacarb susceptibility monitoring, a two‐tiered approach was developed that utilizes diagnostic concentrations and doses in vial LC (30 and 60 µg vial^?1) and gel bait matrix LD (1.0, 1.5 and 2.5 µg insect^?1) formats. CONCLUSIONS: A two‐tiered susceptibility monitoring strategy was developed that includes testing field populations at diagnostic concentrations and doses in first‐tier vial LC bioassays and second‐tier gel bait matrix LD bioassays. The vial method facilitates rapid identification of field strains with reduced susceptibility. The feeding bioassay effectively simulates field exposure to Advion^® and therefore has utility for secondary confirmation of susceptibility shifts and identification of behavioral resistance (i.e. bait aversion). Copyright © 2010 Society of Chemical Industry     

Isozymic discrimination of tropical Australian populations of mesquite (Prosopis spp.): implications for biological control

Isozymic variation was investigated in five Australian populations and six reference collections of mesquite (Prosopis section Algarobia). Within nine enzyme systems, a total of 18 loci were examined in detail. 17 of which were polymorphic. Classification and ordination techniques revealed that two of the Australian populations were referable to P. pallida (syn. P. limensis) and another to a polyploid form of P. juliflora. Although the remaining two Australian populations were closely related, only one showed direct evidence of introgression of genes from P. pallida, and the existence of an additional, undetermined parent species was suggested. Owing to the apparent widespread distribution of P. pallida in northern Australia, it may be expedient to seek potential biological control agents from extra-Australian populations of either this or other species within series Pallidae. However, little is known regarding the general level of host specificity exhibited by the fauna which attacks species in section Algarobia. The overall degree of similarity of the taxa examined in this survey suggests that useful agents for Australian Prosopis might be obtained from the fauna associated with species from both series Pallidae and series Chilenses of section Algarobia.     

Electrophysiological studies on the effect of sesamex upon the action of dieldrin in Blaberus discoidalis

Treatment of the metathoracic ganglion of the cockroach, Blaberus discoidalis, with dieldrin (HEOD) at a concentration of 10^?5M produced changes in spontaneous efferent activity and afterdischarge in efferent pathways. Pretreatment with sesamex markedly reduced the spontaneous activity caused by dieldrin and also reduced the latency of appearance of symptoms from 60 min to nearly 30 min. However, pretreatment with sesamex did not alter the intensity and duration of the dieldrin-induced synaptic afterdischarge. Pretreatment of cockroaches with sesamex did not measurably change the toxicity of dieldrin in vivo.     

Effect of thiamethoxam on cockroach locomotor activity is associated with its metabolite clothianidin

BACKROUND: In the present study, the effect of thiamethoxam and clothianidin on the locomotor activity of American cockroach, Periplaneta americana (L.), was evaluated. Because it has been proposed that thiamethoxam is metabolised to clothianidin, high‐performance liquid chromatography coupled with mass spectrometry was used to evaluate the amount of clothianidin on thiamethoxam‐treated cockroaches. RESULTS: One hour after neonicotinoid treatment, the time spent in the open‐field‐like apparatus significantly increased, suggesting a decrease in locomotor activity. The percentage of cockroaches displaying locomotor activity was significantly reduced 1 h after haemolymph application of 1 nmol g^?1 neonicotinoid, while no significant effect was found after topical and oral administration. However, at 24 and 48 h, all neonicotinoids were able to reduce locomotor activity, depending on their concentrations and the way they were applied. Interestingly, it was found that thiamethoxam was converted to clothianidin 1 h after application, but the amount of clothianidin did not rise proportionately to thiamethoxam, especially after oral administration. CONCLUSION: The data suggest that the effect of thiamethoxam on cockroach locomotor activity is due in part to clothianidin action because (1) thiamethoxam levels remained persistent 48 h after application and (2) the amount of clothianidin in cockroach tissues was consistent with the toxicity of thiamethoxam. Copyright © 2010 Society of Chemical Industry     

Molecular data from up to 130-year-old herbarium specimens do not support the presence of cherry powdery mildew in Australia

A strain of Podosphaera clandestina has been highlighted as a priority pest threat to the Australian cherry industry. Australia currently has no records of powdery mildew on cherry (Prunus avium). P. clandestina is reported to cause disease on a range of Rosaceae genera including Crataegus and Prunus; in Australia, P. clandestina has only been recorded on Crataegus. A recent species revision identified Podosphaera cerasi on P. avium as a separate species from P. clandestina. Therefore, a revision of which powdery mildew species is present in Australia on Crataegus is required to inform Australian plant biosecurity. Reference collection specimens from the Victorian Plant Pathology Herbarium (VPRI) recorded as Podosphaera spp. collected between 1889 to 2008 on cherry and three other host plant genera from Australia and overseas were sampled for DNA extraction and next-generation sequencing (NGS). Sequence data from preserved specimens were successfully mapped to internal transcribed spacer (ITS) sequences of P. clandestina in the strict sense, P. cerasi, and Podosphaera prunicola, and chloroplast matK sequences were used to identify plant hosts. Australian specimens on Crataegus hosts were P. clandestina in the strict sense and specimens on Prunus from the USA were identified as P. cerasi and P. prunicola. The outcome of this study confirmed the powdery mildew on Australian Crataegus specimens to be P. clandestina and none of the cherry powdery mildews (Podosphaera pruni-avium, P. cerasi, or P. prunicola) are present on Australian specimens in the VPRI collection, which suggests they are not present in Australia.     

Potential susceptibility of Australian native plant species to branch dieback and bole canker diseases caused by Phytophthora ramorum

Susceptibility to branch dieback caused by Phytophthora ramorum was tested using a detached branch assay for 66 Australian native plant species sourced from established gardens and arboreta in California. Six of these species were further tested for their susceptibility to bole cankers caused by P. ramorum using a sealed log assay. Isopogon formosus and Eucalyptus denticulata were identified as potentially highly susceptible Australian branch dieback hosts. Thirteen potentially tolerant Australian host species included Banksia attenuata, B. marginata, E. haemastoma, E. regnans, Pittosporum undulatum and Billardiera heterophylla. Eucalyptus regnans was identified as a potentially highly susceptible bole canker host, while E. diversicolor and E. viminalis were considered potentially tolerant species to bole cankers caused by P. ramorum. Phytophthora ramorum was able to infect all 66 species, as confirmed by reisolation. These results extend the known potential host range for P. ramorum, confirm it as a possible threat to Australian plant industries and ecosystems and highlight additional associated hosts that are important in the global horticultural trade, native forests and plantation forestry.     

Invasion status and risk assessment for Salvia tiliifolia,a recently recognised introduction to China

This study corrected the misidentification of an alien species, Salvia tiliifolia, which had been incorrectly identified as S. dugesii (a synonym of S. melissodora) in China. The distribution of S. tiliifolia in China was surveyed and it was inferred that it was probably introduced into Kunming, Yunnan in the 1990s and then spread to adjacent counties of Yunnan and south‐western Sichuan Province. The Australian weed risk assessment (WRA) was used to evaluate its invasive status. To determine the validity of Australian WRA in China, another 25 exotics representing casual alien plants, naturalised plants and invasive plants were tested. The Australian WRA was validated as a legitimate approach in China. Salvia tiliifolia scored 14, falling into the category of invasive plants. While the distribution of S. tiliifolia is currently restricted to Yunnan and a small part of Sichuan and the species has not displayed an adverse impact on local environments yet, the WRA results indicated that the species was a high risk plant. It was recommended that local land managers should monitor this species and take measures to stop its continuing expansion or eradicate it if possible.     

Untersuchungen zur K?ltetoleranz verschiedener St?mme der Deutschen Schabe,Blattella germanica (L.) (Blattodea, Blattidae) unter Laboratoriumsbedingungen

In laboratory investigations, 5 strains of the German cockroach,Blattella germanica, with different origin were tested in respect to their cold tolerance at 0, 5, and 10°C, respectively. The most important results are:An out-door strain of a refuse tip was most tolerant to low temperatures. This ist not surprising, as in other investigations this strain could be observed overwintering in the field outside of the tip.     

Dihydrooxadiazines: Octopaminergic system as a potential site of insecticidal action

Dihydrooxadiazines are structural analogs of octopamine and were compared with octopamine for their ability to compete with [³H]dihydroergocryptine ([³H]DHE) for binding sites on DHE-sensitive receptors, to stimulate adenylate cyclase activity in nervous system homogenates of Periplaneta americana L., and to modulate the action of the peptide proctolin on the oviducal muscles of Locusta migratoria L. [³H]DHE binding was inhibited by low concentrations (μM range) of octopamine, phentolamine, N-demethylchlordimeform (DCDM) and several dihydrooxadiazines. The tested dihydrooxadiazines acted as aminergic agonists in stimulating cyclic AMP production in cockroach nervous system homogenates and did not show additive effects with octopamine, whereas additivity was observed with 5-hydroxytryptamine. The relative potency of octopaminergic antagonists, including mianserin, cyproheptadine, phentolamine, and gramine, to block octopamine-mediated elevation of cyclic AMP production was similar to the rank-order potency of the same antagonists to inhibit dihydrooxadiazine-mediated elevation of cyclic AMP production. Octopamine, 2-(4-bromophenyl)-5,6-dihydro-4H-1,3,4-oxadiazine (4-Br-PDHO), and 8-Br-cyclic AMP caused increased phosphorylation of proteins that are phosphorylated by exogenously added cyclic AMP-dependent protein kinase. These results indicate that the dihydrooxadiazine-induced rise in cyclic AMP levels in homogenates of the cockroach nervous system results directly in activation of an endogenous cyclic AMP-dependent protein kinase. 4-Br-PDHO behaved similarly to octopamine in modulating the action of proctolin-induced contractions in locust oviducal muscles. These observations suggest that dihydrooxadiazines act as octopamine agonists and have an octopaminergic action in modulating the action of proctolin. Thus, it is proposed that dihydrooxadiazines exert at least part of their insecticidal and miticidal actions through interaction with the octopaminergic system.