Biological control of an acarine pest by single and multiple natural enemies Cakmak, I.; Janssen, A.R.M.; Sabelis, M.W.; Baspinar, H. General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. b s t r a c tWhen multiple predator species are introduced to control a single prey species, predator species may act synergistically if the rate of mortality of the prey exceeds the rate of mortality from all single predator species combined. Alternatively, the release of multiple predator species may yield a lower than expected prey mortality due to competitive interactions (including intraguild predation) amongst predators. The question of whether and when multiple natural enemies interact to produce lower or higher prey mortality than each predator species acting alone depends on the details of predator-predator interactions. In this study, we investigated whether combined releases of Phytoseiulus persimilis and Neoseiulus californicus provide better biological control of Tetranychus cinnabarinus on strawberry than releases of each predator species alone. Experiments were conducted in two commercial strawberry fields (Fragaria ananassa Duch. cv. 'Camarosa'). The release of P. persimilis alone and the combined release of N. californicus and P. persimilis reduced the numbers of T. cinnabarinus on strawberry equally. The densities of T. cinnabarinus in the treatment with N. californicus alone were significantly higher than in the other treatments, and this was the only treatment in which the economic injury level was surpassed. The densities of P. persimilis in absence of N. californicus were similar to those in presence of N. californicus. Hence, there was no significant adverse effect of the presence of N. californicus on the densities of P. persimilis. The densities of N. californicus in the absence of P. persimilis were lower than the densities in the presence of P. persimilis, but this difference was not significant. We conclude that, compared to releases with P. persimilis alone, there is no advantage to releasing N. californicus, either alone or in combination with P. persimilis.

Symptoms resembling those associated with phytoplasma presence were observed in pomegranate (Punica granatum L.) trees in June 2012 in the Aegean Region of Turkey (Aydın province). The trees exhibiting yellowing, reduced vigour, deformations and reddening of the leaves and dieback symptoms were analysed to verify phytoplasma presence. Total nucleic acids were extracted from fresh leaf midribs and phloem tissue from young branches of ten symptomatic and five asymptomatic plants. Nested polymerase chain reaction assays using universal phytoplasmaspecific 16S rRNA and tuf gene primers were performed. Amplicons were digested with Tru1I, Tsp509I and HhaI restriction enzymes, according to the primer pair employed. The phytoplasma profiles were identical to each other and to aster yellows (16SrI-B) strain when digestion was carried out on 16Sr(I)F1/R1 amplicons. However, one of the samples showed mixed profiles indicating that 16SrI-B and 16SrXII-A phytoplasmas were present when M1/M2 amplicons were digested, the reamplification of this sample with tuf cocktail primers allowed to verify the presence of a 16SrXII-A profile. One pomegranate aster yellows strain AY-PG from 16S rRNA gene and the 16SrXII-A amplicon from tuf gene designed strain STOL-PG were directly sequenced and deposited in GenBank under the Accession Numbers KJ818293 and KP161063, respectively. To our knowledge, this is the first report of 16SrI-B and 16SrXII-A phytoplasmas in pomegranate trees.

Yellow sticky-traps and a modified Johnson-Taylor suction-trap were used to index the relative population dynamic Of leafhoppers associated with sesame in the east Mediterranean region of Turkey. Comparison of the obtained results signified important differences between both traps. 32 leafhoppers species were caught in the suction-trap while only 18 species were determined on yellow sticky-traps. For most of the leafhopper species, relatively more males were determined on the yellow-traps than in the suction-trap, indicating a higher activity of male leafhoppers during daytime hours. A close relationship between the seasonal flight pattern as indexed by sticky-traps and by suction-trap was only observed for Asymmetrasca deeedens (Paoli) and Empoasca deeipiens Paoli. For most other leafhopper species no or only a very poor correlation for the relative population dynamic was determined between both traps. Important leafhopper vector species, e.g., Circulifer haernatoceps (Mulsant et Rey) and Ornsius orientalis (Matsumura) were I~etter represented in yellow sticky-trap catches than they were in the suction trap.

No abstract