Pheromones in Stored-Product and Material Protection – 35 Years of practical experiences

Seit mehreren Jahrzehnten ist der Einsatz von Lockstoffen gegen Insekten zur Schadensabwehr an Lagergütern und Materialien etabliert. Die Hauptkomponenten der Pheromone aller wirtschaftlich relevanten vorrats- und materialschädlichen Insekten sind bekannt. Zur Früh­erkennung und zur Populationsdichteüberwachung von Schädlingen nehmen Pheromonfallen eine zentrale Position im Konzept der ökonomischen Schadensschwelle und damit im integrierten Vorrats- und Materialschutz ein. Dies gilt vor allem für Sexuallockstoff-Fallen gegen paarungsbereite Männchen von vorratsschädlichen Motten aus den Gruppen der Zünsler (Pyralidae) mit Dörrobst-, Mehl- und Speichermotte und gegen Kleinschmetterlinge (Tineiden) mit Kleider- und Pelzmotte sowie gegen einige Nagekäfer mit Brot-, Tabak- und Gemeiner Nagekäfer. Durch das sogenannte „Monitoring“ können Bekämpfungsstrategien zunächst zeitlich und räumlich optimiert und anschließend auf Erfolg bewertet werden. Neben Sexualpheromonen sind bei einigen Käfern wie beispielsweise den Korn- und Reismehlkäfern auch Aggregationspheromone, die attraktiv auf beide Geschlechter wirken, verbreitet. Ihr Einsatz zur Bekämpfung, d.h. zum Massenfang von Individuen, wie dies im forstwirtschaftlichen Bereich gegen Borkenkäfer nutzbringend durch­geführt wird, hat sich aufgrund mangelnden Erfolgs im Nachernteschutz jedoch nicht etabliert. Neben einem wirtschaftlich orientierten Einsatz von Pheromonfallen kann deren Anwendung auch wertvolle allgemeinbiologische Informationen über Schadinsekten liefern. Wird das „Monitoring“ z.B. im Freiland abseits von Lagerstätten für faunistische Erhebungen durchgeführt, können natürliche Vorkommen von Schädlings­arten ermittelt werden. Dies erlaubt Rückschlüsse auf ihre ursprünglichen Lebensräume und auf mögliche adaptative Szenarien beim Übergang zu einer synanthropen und damit für den Menschen schädlichen Lebens­weise. Zusätzlich werden auf diese Weise natürliche Habitate, die als Reservoire für Schadpopulationen fungieren könnten, aufgespürt und, wenn notwendig, in ein Bekämpfungsprogramm integriert.    The application of pheromone baited traps to control pest insects in stored food or materials of use is well established since the past decades. The main pheromone components of all major stored-product and material pests have been identified. Pest monitoring with pheromone traps is a key factor in integrated pest management to estimate population density build-ups and to define economic threshold levels. Especially male attracting sex pheromones, e.g. for the stored-product pyralids, the clothes moths, and some anobiid beetles, function well in this aspect. Optimal control strategies in space and time are guided by pest population monitoring including efficacy evaluation of the undertaken control measures. Comparatively less successful is the application of aggregation pheromones, which are found in grain and flour beetles and which attract both sexes. Well functioning control of bark beetles through mass-trapping with aggregation pheromones in the forest environment could for various reasons not be implemented for stored-product protection, respectively. Besides an economically driven adoption of pheromone traps, trapping results may also deliver useful information of a pest´s general ecology. The distribution of a pest species outside the synanthropic environment, its occurrence in hidden infestations out-doors can be estimated when monitoring tools are used out-doors, away from any storage facilities. The resulting auteco­logical data can be helpful to detect natural reservoirs of a pest and to possibly reconstruct adaptation scenarios to the men-made environment.   &nbsp

Inhibition of a Secreted Immune Molecule Interferes With Termite Social Immunity

Social immune behaviors are described in a great variety of insect societies and their role in preventing emerging infectious diseases has become a major topic in insect research. The social immune system consists of multiple layers, ranging from the synthesis of external immune molecules to the coordination of individual behaviors into sophisticated collective defensive tasks. But our understanding of how complex group-level behavioral defenses are orchestrated has remained limited. We sought to address this gap in knowledge by investigating the relationship between the external activity of an important immune effector molecule in termites, Gram negative binding protein 2 (GNBP-2) and collective grooming and cannibalism. We reasoned that as an external enzyme capable of degrading entomopathogenic fungi, GNBP-2 can facilitate the spread of pathogenic molecules in the colony, and thus serve to trigger collective defenses in a manner analogous to pathogen-associated molecular signatures (PAMPs) of the individual immune system. To test whether GNBP-2 could play a role in regulating social immune behavior, we experimentally inhibited its fungicidal activity using the glycomimetic molecule, D-d-gluconolactone (GDL) and recorded collective behavioral responses to an infected nestmate. Contrary to expectations, GNBP-2 inhibition did not influence the rate or intensity of grooming of either control or fungus-infected nestmates. By contrast, we found that the probability of being harmed through defensive cannibalistic behaviors was significantly reduced by the inhibition of GNBP-2. Our findings indicate that the regulation of collective immune behaviors may depend in part on the external secretion of an enzyme originating from the individual immune system, but that other cues are also necessary

Surface tuning of wood via covalent modification of its lignocellulosic biopolymers with substituted benzoates: a study on reactivity, efficiency, and durability

Chemical modification of wood applying benzo- triazolyl-activated carboxylic acids has proven to be a versatile method for the durable functionalization of its lignocellulosic biopolymers. Through this process, the material properties of wood can be influenced and specifically optimized. To check the scope and limitations of this modification method, various benzamide derivatives with electron-withdrawing (EWG) or electron-donating (EDG) functional groups in different positions of the aromatic ring were synthesized and applied for covalent modification of Scots pine (Pinus sylvestris L.) sapwood in this study. The bonded amounts of substances (up to 2.20 mmol) were compared with the reactivity constants of the Hammett equation, revealing a significant correlation between the modification efficiency and the theoretical reactivity constants of the corresponding aromatic substitution pattern. The successful covalent attachment of the respective substituted benzamides was proven by attenuated total reflection infrared (ATR-IR) spectroscopy, while the stability of the newly formed ester bond was proven in a standardized leaching test

Searching for biological feedstock material: 3D printing of wood particles from house borer and drywood termite frass

Frass (fine powdery refuse or fragile perforated wood produced by the activity of boring insects) of larvae of the European house borer (EHB) and of drywood termites was tested as a natural and novel feedstock for 3D-printing of wood-based materials. Small particles produced by the drywood termite Incisitermes marginipennis and the EHB Hylotrupes bajulus during feeding in construction timber, were used. Frass is a powdery material of particularly consistent quality that is essentially biologically processed wood mixed with debris of wood and faeces. The filigree-like particles flow easily permitting the build-up of wood-based structures in a layer wise fashion using the Binder Jetting printing process. The quality of powders produced by different insect species was compared along with the processing steps and properties of the printed parts. Drywood termite frass with a Hausner Ratio HR = 1.1 with ρBulk = 0.67 g/cm3 and ρTap = 0.74 g/cm3 was perfectly suited to deposition of uniformly packed layers in 3D printing. We suggest that a variety of naturally available feedstocks could be used in environmentally responsible approaches to scientific material sciences/additive manufacturing

High-Throughput Cultivation for the Selective Isolation of Acidobacteria From Termite Nests

Microbial communities in the immediate environment of socialized invertebrates can help to suppress pathogens, in part by synthesizing bioactive natural products. Here we characterized the core microbiomes of three termite species (genus Coptotermes) and their nest material to gain more insight into the diversity of termite-associated bacteria. Sampling a healthy termite colony over time implicated a consolidated and highly stable microbiome, pointing toward the fact that beneficial bacterial phyla play a major role in termite fitness. In contrast, there was a significant shift in the composition of the core microbiome in one nest during a fungal infection, affecting the abundance of well-characterized Streptomyces species (phylum Actinobacteria) as well as less-studied bacterial phyla such as Acidobacteria. High-throughput cultivation in microplates was implemented to isolate and identify these less-studied bacterial phylogenetic group. Amplicon sequencing confirmed that our method maintained the bacterial diversity of the environmental samples, enabling the isolation of novel Acidobacteriaceae and expanding the list of cultivated species to include two strains that may define new species within the genera Terracidiphilus and Acidobacterium

Outdoor trapping and genetical characterization of populations of the webbing clothes moth Tineola bisselliella (Lepidoptera: Tineidae) in the broader area of Berlin

Adapted and effective pest management strategies for the protection of irreplaceable culture heritage as well as for the prevention of damages in households and warehouses are based on reliable information about the presence and distribution of the pest organisms. Monitoring the webbing clothes moth Tineola bisselliella at thirteen outdoor stations in the broader area of Berlin give a first idea of their occurrence in an urban area and the hinterlands. The results demonstrate a seasonal abundance in the city and a missing of this species in the countryside. Data suggest a synanthropic occurrence of the webbing clothes moth rather than an invasion from natural reservoires. Possible molecular examinations on the species and subspecies level are presented to analyze the gene flow between populations and give an impression of species mobility as well as pathways of infestation

Termite resistance of pine wood treated with nano metal fluorides

Fluorides are well-known as wood preservatives. One of the limitations of fluoride-based wood preservatives is their high leachability. Alternative to current fluoride salts such as NaF used in wood protection are low water-soluble fluorides. However, impregnation of low water-soluble fluorides into wood poses a challenge. To address this challenge, low water-soluble fluorides like calcium fluoride (CaF2) and magnesium fluoride (MgF2) were synthesized as nanoparticles via the fluorolytic sol−gel synthesis and then impregnated into wood specimens. In this study, the toxicity of nano metal fluorides was assessed by termite mortality, mass loss and visual analysis of treated specimens after eight weeks of exposure to termites, Coptotermes formosanus. Nano metal fluorides with sol concentrations of 0.5 M and higher were found to be effective against termites resulting in 100% termite mortality and significantly inhibited termite feeding. Among the formulations tested, the least damage was found for specimens treated with combinations of CaF2 and MgF2 with an average mass loss less than 1% and visual rating of “1”. These results demonstrate the efficacy of low water-soluble nano metal fluorides to protect wood from termite attack.Peer Reviewe