Springer Science and Business Media LLC

Conservation biological control by means of ground cover offers an interesting alternative to chemical control. A complex of Thysanoptera (thrips) species inhabits citrus, some of which are considered pests. This study investigated the effect of ground cover management on thrips species composition, distribution, and seasonal abundance in four commercial clementine mandarin (Citrus clementina Tanaka) orchards. Three soil management systems were compared: resident vegetation, Festuca arundinacea Schreber (Poales: Poaceae), and bare soil. Cover management affected thrips species diversity and abundance. Two of the main species causing fruit damage in Spanish citrus, Frankliniella occidentalis (Pergande) and Thrips tabaci Lindeman, were abundant in the resident ground cover. However, their abundance was strongly depressed in the F. arundinacea cover. The resident vegetation cover could provide a range of suitable host plants supporting populations of potential thrips pest species beyond the citrus blooming period. The F. arundinacea cover, which hosted Poaceae-specific thrips species, could also provide alternative food sources for Phytoseiidae mites. These predatory mites could reduce populations of potential thrips and other citrus pests below economic injury level. Our results confirm the suitability of F. arundinacea as a cover crop for clementine mandarins.

Mealybugs (Hemiptera: Coccomorpha: Pseudococcidae) constitute important agricultural pests that often require control measures. Different mealybug taxa might, however, react differently to natural enemies and pesticides so that appropriate control measures against mealybugs rely heavily on the correct species identification. The mealybug Planococcus ficus (Signoret) is the most damaging scale insect infesting vineyards worldwide. Despite its economic impact, the taxonomic status of this mealybug species is still unclear, and recent studies suggest the possibility that P. ficus from eastern (i.e., Egypt) and western (i.e., France) Mediterranean regions may correspond in fact to two distinct species. The purpose of this work was to deepen our current knowledge of putative P. ficus from eastern Mediterranean using molecular tools and morphological analysis and test for the existence of cryptic species within P. ficus. Mealybug samples were collected from Egyptian vineyards to better characterize the genetic diversity and analyze the population structure of putative P. ficus along the eastern Mediterranean. We also estimated the phylogenetic relationships among the P. ficus complex haplotypes in different vineyard regions worldwide and analyzed the morphological characters of the different clades obtained. Morphological and molecular analyses confirmed the existence of two species: P. ficus (Signoret) s.str. and P. vitis (Niedielski), a species that was previously synonymized as P. ficus. These results have direct implications for pest management and could explain the lack of success in previous implementations of biological control programs against this pest in several vineyard regions.

Biological and other alternative control methods were tested against the woolly beech aphid (Phyllaphis fagi). Field applications of mineral oil to the egg stage reduced initial aphid population by 75%, but only when the eggs were exposed to oil close to the time of hatching. Earlier oil treatments had no effect. Bioassays with the insect pathogenic fungus Lecanicillium lecanii (Verticillium lecanii) in the commercial formulation Vertalec® were conducted using different dosages, i.e. 1 × 106 ml−1 (recommended dosage) and 2 × 107 ml−1. Both nymphs and adults were susceptible to fungal infection at both dosages. The existence of a dense wax-covering in adult P. fagi had no protective effect against fungal infection. In bioassays where leaves were treated with the recommended dosage of Vertalec, there was no difference in mortality measured after 14 days between adult P. fagi with an intact wax-layer and adult P. fagi where the wax-layer had been removed. In semi-field trials with two L. lecanii treatments at the recommended dosage, the aphid population was reduced. There was no enhanced effect with the addition of an additive to the fungal suspension or from covering the plants with a polypropylene cover. The results reveal potential alternative control methods against P. fagi populations. However, adequate control with L. lecanii probably requires several treatments as opposed to the two that were tested in the present experiment. Furthermore, efficiency may depend on summer temperatures and humidity.

Bei der Großen Getreideblattlaus,Macrosiphum avenae (F.), und der Haferblattlaus,Rhopalosiphum padi (L.), wurde in norddeutschen Weizenanbaugebieten an sieben Weizensorten die Beziehung zwischen Befallsstrecke und Anzahl Blattläusen pro Ähre untersucht. Es gelang, für Einzelbefall durchM. avenae und für Mischbefall durch beide Arten eine Tabelle aufzustellen, aus der für die jeweilige Befallsstrecke pro Ähre die Anzahl Blattläuse abgelesen werden kann. Bei Mischbefall ist die Besiedlung der Ähre dichter als bei Einzelbefall durchM. avenae. Die Anwendungsmöglichkeiten der erarbeiteten zeitsparenden Methode werden diskutiert.

Pheromonfallen zur Prognose von Wicklerflügen im Obstbau werden seit 1971 in Süddeutschland verwendet. Die Fallen- und Anwendungstechniken sowie die Ergebnisse von dreijährigen Freilandversuchen mit Lockstoffen beim ApfelwicklerLaspeyresia pomonella L. im Vergleich zu Lichtfallen werden vorgestellt. Dabei sind synthetische Lockstoffe fängiger als lebende Weibchen. Die Fangmethode hat sich im Apfelwicklerwarndienst zur Feststellung des örtlichen und zeitlichen Flugverlaufs bewährt und kann nun in die Praxis übertragen werden, während bei Apfelschalenwickler (Adoxophyes reticulana HB.) und Pflaumenwickler (Grapholitha funebrana Tr.) noch weitere Versuche mit Lockstoffen vor der Praxisreife angestellt werden müssen.

Entomopathogenic nematode (EPN) species richness merits studies towards making rational decisions for effective management of Caribfly, Anastrepha suspensa (Loew) in southern Florida. Competition for Caribfly and efficacies of EPN biodiversity were examined under laboratory conditions. Similar EPN species treatments to Caribfly-infested fruits, periodically obtained from the ground in groves which were also infested by the parasitoid Diachasmimorpha longicaudata Ashmead (Braconidae), were studied in a series of field trials. Treatments with individual EPN species and their mixtures caused similar mortalities of Caribfly larvae, though the various EPN species competed for larvae in multiple-species treatments. Laboratory trials showed that mortalities of EPN-treated Caribfly pupae were mostly inversely related to EPN diversity. In the field, population densities of emerging adult Caribfly increased with increasing number of EPN species combined in treatments. Thus, single-EPN species treatments proved to be more effective for the management of fruit-to-soil stages of Caribfly. Relative to controls, the proportions of surviving adult Caribfly observed in EPN treatments with Heterorhabditis bacteriophora (exotic in Florida), Steinernema feltiae (exotic EPN) and Heterorhabditis indica (the endemic species) in field plots were 22.5 ± 6, 45 ± 13 and 47 ± 13%, respectively. Number of emerging D. longicaudata in each of EPN species treatments was similar to that observed in control, suggesting that none of the EPN species significantly affected the emergence of D. longicaudata, a parasitoid of Caribfly. Heterorhabditis bacteriophora will be more promising, with insignificant side effects on D. longicaudata in Caribfly-integrated pest management.

We reconstructed the phylogeography of European populations of Monochamus galloprovincialis (Coleoptera, Cerambycidae), the European vector of the pinewood nematode, Bursaphelenchus xylophilus. This study investigated the Quaternary history of M. galloprovincialis and tested whether environmental parameters and/or host tree species influenced the genetic structure of M. galloprovincialis populations. Twelve polymorphic microsatellite loci and a Bayesian analysis were applied to 1098 individuals of M. galloprovincialis from 45 European locations. The continental populations formed five main genetic clusters, typical of postglacial recolonization routes observed for temperate biota associated with pine trees. The distribution of clusters formed boundaries along mountain ranges, indicating a potential role of elevation as a large-scale barrier to dispersal for this species. The correlation between environmental parameters and the distribution of genetic clusters of M. galloprovincialis was investigated using a partial redundancy analysis and showed an effect of precipitation rather than host tree species. From an applied perspective, these results suggest that climatic conditions and elevation may constitute barriers to the dispersal of M. galloprovincialis and the associated PWN.

The female sex pheromone ofL. decemlineata is an aphrodisiacum, switching on mating behaviour in contacting males. A biotest is described to estimate quantitatively the exciting power of a subject (female, isolated elytrae, glass dummy coated with extract) to males. The pheromone is present only in fertile females, also in freshly killed ones. It can be extracted by organic solvents. A dummy imitating a beetle's abdomen and contaminated with the residue of a female s wash solution is exciting to males too. Suitable solvents are ethylalcohol, acetonet, hexane. By this, the pheromone of 0,1 female is detectable. The residue can be taken up again with the same or an other solvent. The solution can be stored at −18°C without significant losses, but at temperatures>+5°C their efficacy diminishes during 2 weeks. The exciting efficacy of the dry residue desreases to about 50% during nearly 4 weeks (at+22°C) or 9 weeks (at+5°C). The pheromone resists heating to about+160°C and is destroyed at higher temperatures.