Population genetic structure of Raffaelea quercus-mongolicae indicates a recent fungal introduction event to Jeju Island from inland areas of South Korea

Raffaelea quercus-mongolicae, a mycangial symbiont of a wood-boring ambrosia beetle, Platypus koryoensis (Coleoptera: Curculionidae: Platypodidae), has been associated with the mass mortality of Korean oak trees in South Korea. Systemic wilt from the inoculation of oak trees with R. quercus-mongolicae has caused significant damage to forest ecosystems in the country. Despite the continued spread of this fungus across the country since the first discovery of the disease, little is known regarding its biology. During a recent survey carried out to investigate the status of oak wilt diseases on Jeju Island, South Korea, visible signs of bark beetle attack, including bark beetle frass and galleries, were consistently observed in Quercus serrata, and R. quercus-mongolicae was successfully recovered from the trees. To determine whether the pathogen was introduced from inland areas of the country to Jeju Island, the genetic diversity and population structure of R. quercus-mongolicae isolates collected from various geographical regions and hosts in the country were investigated using a combination of eight microsatellite markers designed from the genome of the fungus in this study. The results showed lower levels of genetic diversity for the population from Jeju Island compared to those from inland areas of the country. This suggests that a limited number of individuals were recently introduced to Jeju Island, resulting in a new disease problem in the area.     

Environmental risk assessment of carbosulfan on target and non-target beetles when used as white grub larvicide in the cork oak forest of Mamora (Morocco)

The protection of new cork oak plantations against the larvae of the beetle Sphodroxia maroccana (Melolonthidae), which destroy the roots of newly planted trees, was provided for many years in the forest of Mamora in Morocco by the use of carbosulfan, usually formulated as dry granules for direct incorporation into the soil at planting. Ecotoxicological tests were conducted in the laboratory on S. maroccana and on two non-target beetle species, namely Pachychila obtusecostata and Pimelia platynota (Tenebrionidae), to measure the acute effects of carbosulfan and evaluate the potential risk associated with inappropriate practices. The mortality was measured at both 4 d and 7 d after ingestion of a known quantity of carbosulfan. The recommended dose by the manufacturer was exceeded by at least four-fold in the Mamora Forest, with obvious environmental risks. Risks were identified for wildlife when the pesticide is misused and spread on the soil around the plants.     

Red Oak Borer, Enaphalodes rufulus (Coleoptera: Cerambycidae), in the Ozark Mountains of Arkansas, U.S.A.: An Unexpected and Remarkable Forest Disturbance

A complex interaction of multiple factors has resulted in an oak decline event in oak-hickory forests of the Ozark Mountains of Arkansas and Missouri, U.S.A. The most striking feature of this situation is an unprecedented population explosion of red oak borer, a species of cerambycid beetle, Enaphalodes rufulus (Haldeman), which appears to be causing extensive mortality to mature red oaks (Quercus, subgenus Erythrobalanus). The insect is a native species, historically a minor pest of oaks, found throughout the eastern United States. Beetles normally reproduce in living oaks, as larvae initially feed in phloem tissue and subsequently bore into xylem where pupation occurs. The life cycle is two years in length and synchronous adult emergence occurs in odd-numbered years. Data from previous research indicate average attack densities of less than four per tree with a high of 71 on a single tree. Historical emergence densities are similarly low and the highest reported was 15 adults from one tree. Our research is concerned with understanding factors contributing to this outbreak; developing sampling methods for red oak borer; assessing oak mortality; and evaluating site and stand conditions associated with the current outbreak. Results of our initial sampling reveal dramatically higher average attack densities of 244 per m2 and emergence densities of 18 per m2 of bark surface area. We confirm a three-week period of adult emergence and activity during mid-June to early July. We also report on possible management responses by federal and state agencies to this remarkable epidemic and oak mortality crisis.     

A multiplex real-time PCR assay enables simultaneous rapid detection and quantification of bacteria associated with acute oak decline

Acute oak decline (AOD) is a syndrome affecting mature oak trees and is characterized by stem bleeds from vertical fissures on trunks, and inner bark necrosis caused by a polybacterial consortium, in which Gibbsiella quercinecans and Brenneria goodwinii, and to a lesser extent Rahnella victoriana and Lonsdalea britannica, play key roles. Here we report a novel multiplex real-time PCR assay that enables simultaneous and rapid detection and quantification of these four bacterial species from stem bleed swabs. Experiments with axenic cultures were performed to determine specificity and sensitivity of the multiplex quantitative PCR (qPCR). Whilst the primer/probe set for B. goodwinii was species-specific, primer/probe sets for the other three species were able to identify other members of their respective genera. There was no cross detection of genera within the multiplex qPCR, and non-target bacteria were not detected. The multiplex AOD assay had differential sensitivity for each bacterial species. The assay was evaluated on swab samples collected from stem bleeds of declining oak trees at a site in south-east England and was able to detect all four bacterial species. Absolute quantification of the bacteria from swab samples was possible through the inclusion of a standard curve prepared from dilutions of gene copy standards. This diagnostic tool will facilitate rapid detection of AOD-associated bacteria from samples that can easily be taken by non-specialists without specific training, and will also find application in other experimental work such as pathogenicity and control trials.     

De Rijpingsvreterij van den Ooftboom-Spintkever,Scolytus Mali Bechst. (Col.: Scolyti Dae)

Summary 1. The maturation feeding ofScolytus mali Bechst. is described for the first time. 2. This feeding takes place at the base of the spurs (short-shoots) where a short hole is bored by the young beetle. 3. The damaged spurs whither and die, finally dropping to the ground. 4. The described infestation originated from a dead apple, pear and plum tree in the neighbourhood, the bark of which was heavily perforated by the emerging beetles. The breeding galleries are shortly described; attention is further drawn to the occurrence of numerous horizontal galleries the significance of which is not yet clear. 5. The parasites reared from the infested wood are enumerated. The most numerous is a Chalcid, subfam. Eulophinae, viz.Elachistus leucogramma Rtzb. but it occurred in a small percentage, perhaps 2–5%, only. 6. Removing and destroying all dead or dying fruit trees, which are infested by these Scolytids, is strougly advised.      

Analysis of the genetic diversity and phylogenetic relationships of <Emphasis Type="Italic">Biscogniauxia mediterranea</Emphasis> isolates associated with cork oak

Biscogniauxia mediterranea is one of the most frequent fungal pathogens involved in cork oak decline in the Mediterranean Basin, causing charcoal canker. In Portugal, this disease is widespread on adult declining trees but nowadays it increasingly affects young trees and exhibits atypical symptoms, leading to the hypothesis that some change in the fungus may have occurred. In order to evaluate the genetic diversity and phylogenetic relationship of B. mediterranea associated with cork oak, 102 isolates were obtained from young and adult trees of Quercus suber and other hosts species with different disease expression, from several Mediterranean countries. The collection of isolates was analyzed by individual and multigene phylogenies using Maximum-Likelihood approach based on nucleotide sequences of the internal transcribed spacers of ribosomal DNA, translation elongation factor 1-α and β-tubulin genes, and by microsatellite-primed PCR profiles. Sequence analyses separated the Mediterranean isolates from those from other regions, while MSP-PCR analysis revealed relevant but unstructured diversity among the Mediterranean isolates under study, making this a monophyletic but diverse population. Considering the adaptive capacity of the fungus in the Mediterranean-climate ecosystems and the present climatic change scenario, all conditions are gathered to favor aggravation of the disease in cork oak stands.     

De rijpingsvraat van de eikensp intkever,scolytus intricatus ratzeb

Summary The oak barkbeetle,Scolytus intricatus Ratz., is, in normal times, a rather uncommon insect in the Netherlands. After the outbreak of the war, however, it developed in large numbers in oak trees, damaged bij direct war action. The presence of the beetle is indicated bij its maturation feeding, consisting in affecting and killing a large number of spur shoots during May. Bij their boring activity the young beetles nearly cut off these shoots near their base, soon they wither and fade becoming clearly visible in the green canopy. Stormy weather causes them to drop off green so that the ground may become densily covered with these shoots.A rectification is added concerning the maturation feeding ofSc. laevis Bechst., as described formerly by the same author. The identification of the beetle in question proved to be wrong. The maturation feeding described refers to the commonSc. rugulosus Ratz.     

树栖真菌对扩散型松材线虫生活史的影响

 松材线虫病是一种涉及多个生物因子的复杂病害系统,其病原松材线虫的生活史受媒介昆虫、寄主、树栖真菌和伴生细菌等多种因素影响。利用感染松材线虫病的马尾松林内的两种优势内栖真菌的3个菌株,松球壳孢(Sphaeropsis sapinea)E11、MHS7.3和小孢拟盘多毛孢(Pestalotiopsis microspora)M32,接种于松褐天牛模拟蛹室,研究松褐天牛蛹期和羽化过程松材线虫种群动态,以及松褐天牛携带扩散型松材线虫的动态变化。结果表明,天牛发育处于蛹期时,松材线虫主要以扩散型三龄幼虫(J_Ⅲ)附着于天牛体表;发育至羽化期时,松材线虫主要以扩散型四龄幼虫(J_Ⅳ)位于天牛体内。不同优势内栖真菌接种处理下,松褐天牛携带的扩散型幼虫数量的大小顺序为:小孢拟盘多毛孢M32>松球壳孢E11>松球壳孢MHS7.3,这与模拟蛹室中松材线虫种群的大小顺序是一致的,表明松褐天牛携带的线虫数目与蛹室中线虫种群的大小关系密切。在松褐天牛携带的J_Ⅲ、J_Ⅳ和扩散型幼虫(J_Ⅲ＋J_Ⅳ)占线虫种群比例方面,松球壳孢E11和MHS7.3均大于小孢拟盘多毛孢M32,显示不适宜繁殖的真菌能促进群体内更多个体转化为扩散型虫态。J_Ⅳ在蛹期的第二天即从天牛体内分离得到,但数量极少,随着J_Ⅲ在羽化前达到最大值,J_Ⅳ也开始大量出现,预示着较大J_Ⅲ种群数量可能是J_Ⅳ大量发生的基础条件之一。研究结果表明在松材线虫的扩散过程中,松林优势树栖真菌对媒介天牛携带的松材线虫数量产生显著影响。     

Comparison of the reproductive potential of <Emphasis Type="Italic">Monochamus galloprovincialis</Emphasis> on two pine species under laboratory conditions

Monochamus galloprovincialis Olivier (Coleoptera: Cerambycidae) is one of the vectors of the pinewood nematode Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle (Nematoda: Parasitaphelenchidae), the causal agent of pine wilt in susceptible pine trees. It is therefore important to study both the biological and ecological characteristics of the beetle. In this study reproductive potentials of female beetles reared on two pine species were investigated under laboratory conditions and compared using fertility tables constructed for beetles reared on each tree species. Beetle population parameters were compared between tree species. The intrinsic rate of increase and associated population parameters of beetles reared on Pinus sylvestris L. were consistently higher than those reared on P. nigra Arnold. This result suggests that P. sylvestris has a significantly greater positive effect on the reproductive potential of M. galloprovincialis populations than does P. nigra.     

Report of a pest risk analysis for Platypus parallelus (Fabricus, 1801) for Turkey

Invasive bark and ambrosia beetles (Curculionidae: Scolytinae and Platypodinae) are increasingly responsible for damage to forests, plantations and orchards worldwide. They are usually closely associated with fungi, which may be pathogenic causing tree mortality. Stressed or weakened trees are particularly subject to attack, as is recently felled, non‐treated wood. This PRA report concerns the ambrosia beetle Platypus parallelus (Euplatypus parallelus, Fabricus, 1801) (Coleoptera: Scolytidae), which was detected in official controls. The PRA area is Turkey. P. parallelus is not on the A1 or A2 list for Turkey but the Regulation on Plant Quarantine (3 December 2011‐OJ no: 28131) Article 13 (5) indicates that pests which are assessed to pose a risk for Turkey following PRA that are not present in the above lists and plants, wood, plant products and other materials contaminated by these organisms are banned from entry into Turkey. This risk assessment follows the EPPO Standard PM 5/3(5) Decision‐support scheme for quarantine pests and uses the terminology defined in ISPM 5 Glossary of Phytosanitary Terms. This paper addresses the possible risk factors caused by Platypus parallelus (Euplatypus parallelus, Fabricus, 1801) in Turkey.     

Communication to the Editor Protection of Wood against the House Longhorn Beetle Hylotrupes bajulus with Sodium Chloride and Potassium Chloride

The effectiveness of aqueous solutions of sodium chloride and potassium chloride as wood preservatives was tested against larvae of the house longhorn beetle Hylotrupes bajulus (L.). Immersion of pine (Pinus sylvestris L.) blocks for 24 h provided only a shallow protective layer. In a test series according to EN 46 a concentration of 200 g litre^-1 potassium chloride was required for complete larval mortality within 12 weeks; 200 g litre^-1 sodium chloride failed to achieve this. With vacuum impregnation in tests according to EN 47 a concentration of 100 g litre^-1 sodium chloride achieved complete mortality of larvae within four weeks. Vacuum impregnation of 100 g litre^-1 potassium chloride attained complete mortality only after 12 weeks. Ovipositing female beetles did not avoid wooden blocks treated with either salt. © 1997 SCI.     

The dietary toxicity of deltamethrin to the carabid,Nebria brevicollis (F.)

Batches of adult Nebria brevicollis (F.) (Coleoptera: Carabidae) were provided with freeze-killed aphids, Metopolophium dirhodum (Walk.) (Homoptera: Aphididae), that had been treated topically with 30 ng a.i. deltamethrin. Beetles in different hunger states were found to consume contaminated aphids, but they consumed significantly fewer aphids than control beetles. The mean numbers of contaminated aphids eaten increased with hunger-level, from 2.5 aphids per beetle for those provided with food 24 h before exposure, to 4.5 aphids per beetle for those provided with food 120 h prior to exposure. The highest mortality that occurred over the following six days after consumption of contaminated aphids was 27% for the beetles that had been fed 120 h before exposure and the lowest was 13% for the beetles that had been fed 24 and 48 h prior to exposure. A regurgitation response was observed in 53–80% of the beetles that had consumed deltamethrin-treated aphids. The beetles that survived consumption of treated aphids showed a short-term reduction in mean numbers of untreated aphids consumed relative to the control beetles. Dietary and topical dose-response data for deltamethrin and N. brevicollis were compared by probit analysis and maximum likelihood procedures. The dietary exposure probit line had a significantly steeper slope than the topical exposure probit line but the two lines occupied similar positions along the dose axis. The steepness of the dietary exposure probit line may be partly explained by the regurgitation response shown by the beetles, which causes water loss and may amplify toxic effects. The results indicated that the consumption of deltamethrin-contaminated prey may be an important cause of predator mortality soon after pesticide application.     

Beetles (Coleoptera) caught with pheromones of Gnathotrichus retusus and G. sulcatus (Col., Scolytidae) in southern Finland

The ambrosia beetle Gnathotrichus materiarius, which originally came from North America, was discovered in southern Finland in 1996. In 1997, using Norwegian drainpipe traps baited with pheromones of Gnathotrichus retusus and G. sulcatus, we collected beetles in the region where the first specimen had been caught in order to determine whether this potential pest species had become established in the area. Samples from a total of 16 traps included 79 species of beetles and 719 individuals, but no specimens of G. materiarius. The most abundant species in the samples were the ambrosia beetles Xyleborus dispar and Trypodendron lineatum. Several predators and other associates of bark beetles were also captured. The majority of the beetles caught were saproxylic species.     

Beetles (Coleoptera) caught with pheromones of Gnathotrichus retusus and G. sulcatus (Col., Scolytidae) in southern Finland

The ambrosia beetle Gnathotrichus materiarius, which originally came from North America, was discovered in southern Finland in 1996. In 1997, using Norwegian drainpipe traps baited with pheromones of Gnathotrichus retusus and G. sulcatus, we collected beetles in the region where the first specimen had been caught in order to determine whether this potential pest species had become established in the area. Samples from a total of 16 traps included 79 species of beetles and 719 individuals, but no specimens of G. materiarius. The most abundant species in the samples were the ambrosia beetles Xyleborus dispar and Trypodendron lineatum. Several predators and other associates of bark beetles were also captured. The majority of the beetles caught were saproxylic species.     

Lateral transfer of a phytopathogenic symbiont among native and exotic ambrosia beetles

Different ambrosia beetle species can coexist in tree trunks, where their immature stages feed upon symbiotic fungi. Although most ambrosia beetles are not primary pests and their fungal symbionts are not pathogenic to the host tree, exceptional situations exist. Notably, Xyleborus glabratus carries a phytopathogenic symbiont, Raffaelea lauricola, which causes laurel wilt, a lethal disease of some Lauraceae species. Both X. glabratus and R. lauricola are natives of Asia that recently invaded much of the coastal plain of the southeastern USA. This study examined ambrosia beetles that breed in susceptible trees in Florida (USA), including avocado (Persea americana), redbay (P. borbonia) and swampbay (P. palustris). Raffaelea lauricola was recovered from six of eight ambrosia beetle species that emerged from laurel wilt‐affected swampbay trees, in addition to X. glabratus. Controlled infestations with cohorts of the six species other than X. glabratus revealed that each could transmit the pathogen to healthy redbay trees and two could transmit the pathogen to healthy avocado trees; laurel wilt developed in five and one of the respective beetle × host interactions. These results indicate flexibility in the lateral transfer of a non‐native ambrosial fungus to other ambrosia beetles, and for the first time documents the transmission of a laterally transferred phytopathogenic symbiont by new ambrosia beetle species. Additional work is needed to determine whether, or to what extent, the new beetle × R. lauricola combinations play a role in spreading laurel wilt.     

Optimizing a protein-specific ELISA for the detection of protein-marked insects

A series of tests were conducted to determine if the sensitivity and efficiency of an established rabbit immunoglobulin (IgG)-specific enzyme-linked immunosorbent assay (ELISA) could be improved for detecting a protein mark on insects. Five variations of ELISA were examined for their ability to detect a rabbit IgG mark on the convergent lady beetle, Hippodamia convergens Guérin-Méneville. The conventional sandwich ELISA was the most sensitive immunoassay based on the strength of the ELISA reaction and the proportion of individuals scoring positive for rabbit IgG. ELISAs were also conducted on rabbit IgG-marked beetles that were either homogenized or soaked in sample buffer prior to the assay. Results showed that homogenized beetles yielded higher ELISA values in the conventional ELISA than soaked beetles, but the qualitative response (i.e., percentage scoring positive for the mark) was about the same for up to 18 days after marking. Therefore, in some instances, simply soaking an individual beetle might be a viable alternative to the labour-intensive homogenization of the sample. Sandwich ELISAs with immunoreagent incubation intervals held constant at 5, 10, 20, or 60 min were also examined for their ability to detect rabbit-IgG-marked beetles. Results showed that the ELISA with immunoreagent incubations of 60 min yielded a significantly higher ELISA reading than the shorter intervals. However, all the marked beetles examined scored positive for the presence of rabbit IgG, regardless of the incubation interval. Finally, a test was conducted to determine if the conventional ELISA could also detect the presence of relatively inexpensive normal rabbit serum on marked beetles. Beetles marked with rabbit serum diluted one part rabbit serum to one, four, or eight parts water yielded statistically similar ELISA values to those beetles marked with the conventional rabbit IgG mark.     

我国栎类植物蛀干蛀果害虫及其天敌多样性研究进展

蛀干蛀果害虫是威胁我国栎类森林生态系统安全的重要因素。本文针对我国栎类植物蛀干蛀果害虫的物种多样性、地理分布情况、高风险外来入侵性害虫种类及其寄生性天敌种类进行了综述。目前我国有150余种栎类植物蛀干蛀果害虫,其中以天牛科Cerambycidae害虫最多,有64属96种,其次为小蠹科Scolytidae害虫,有13属29种;有10余种高风险入侵性害虫需加以重点防范;这些害虫的寄生性天敌目前仅报道了20余种。今后应在栎类植物蛀干蛀果害虫的分布区系、天敌资源调查、害虫及其天敌遗传多样性和害虫暴发关键诱发因子等方面开展更深入的研究。     

Olfactory and visual responses of the longlegged chafer Hoplia spectabilis Medvedev (Coleoptera: Scarabaeidae) in Qinghai Province, China

BACKGROUND: Monitoring traps and control methods are needed for the long‐legged chafer, Hoplia spectabilis Medvedev, which has recently reached outbreak numbers in pastureland of Qinghai Province, China. RESULTS: Field trapping experiments, using cross‐pane funnel (barrier) traps, showed that H. spectabilis adults were not significantly attracted to branches of the host plant Dasiphora fructicosa (L.) Rydb. However, beetles were slightly attracted to similar host plant branches infested by conspecific beetles, possibly owing to weakly attractive volatiles, primarily (Z)‐3‐hexenyl acetate, released from beetle‐damaged host leaves. This compound was weakly attractive when released from traps. However, H. spectabilis beetles showed strong visual responses to yellow‐ or white‐painted trap panes, with weaker responses to blue, red or green panes, and least response to black panes. Black traps at 0.2–1.5 m above ground intercepted significantly more beetles than traps at 2.5 m. The mean flight height based on trap catches was 0.88 m (SD = 0.76), yielding an effective flight layer of 1.9 m. Flight response of beetles to colored barrier traps occurred between 10:00 and 18:00, and peaked between 12:00‐14:00, when daily temperatures reached their maximum. CONCLUSION: Unbaited yellow or white cross‐pane funnel traps are recommended for both monitoring and mass‐trapping programs against this economically and ecologically important scarab beetle. Copyright © 2010 Society of Chemical Industry     

Comparison of the Susceptibility of Quercus petraea, Q. robur and Q. rubra to Collybia fusipes

Collybia fusipes is the cause of a root rot of Quercus petraea (sessile oak), Q. robur (pedunculate oak) and Q. rubra (red oak). This parasite is often reported to cause problems in stands of red oaks and field evidence suggests that this North American oak species is more susceptible than the two European oak species. Young saplings of the three oak species and of chestnut, Castanea sativa, in the glasshouse, and also mature sessile and red oaks growing in the same stand were inoculated with C. fusipes to compare their susceptibility. Red oak, both as young seedlings and mature trees, was more susceptible to C. fusipes than sessile oak. Chestnut seedlings were as susceptible as sessile oak. Susceptibility of pedunculate oak seedlings was intermediate between red oak and sessile oak. In one experiment this species was significantly less susceptible than red oak, and in the other it was as susceptible.     

Pest status and control of blister beetles in West Africa

Abstract

During recent years, blister beetles have gained importance in species diversity and as pests of food crops in West Africa. Among the 97 species reported, Psalydolytta fusca Oliv, and P. vestita Duf. are economically important beetle species. Beetle abundance is generally associated with the flowering of crops in a region. Regular intensive weeding and early crop establishment are recommended for pest management in food crops. Global pest control strategies are discussed in the context of subsistence agriculture.