Natural and insecticide-free methods for protecting wood piles from bark beetles - using the example of the ash bark beetle (Hylesinus fraxini [Panzer, 1779]) on Common Ash (Fraxinus excelsior [L.])

This paper is investigating the insecticide-free protection of ash wood piles through the use of semiochemical dispensers with allochthonous kairomones to control ash bark beetle populations. For this purpose, borehole counts and brood gallery analyses were carried out on log piles of ash wood stored in the forest. Studies have shown that Hylesinus fraxini is repelled by the attractant dispenser with the substance mixture Sexowit, which was actually developed to catch Ips sexdentatus. In addition, the substance mixture has an aggregating effect on various bark beetle antagonists. This causality should be used to find a form of application to protect freshly stacked ash wood from H. fraxini infestation. A recommended form of application should be transferable to other bark beetle- and tree species and substances. In adaptation to the so-called Island Method of bark beetle traps, the wood piles of the five test variants were also arranged like islands. Commercially available Sexowit pheromone dispensers were used, which were attached to the piles. Besides a control without Sexowit dispenser there were test treatments with one, two, four and nine Sexowit dispensers.Within the scope of the investigation, effects between the tested variants could be determined and a recommended application method derived. Compared to control most effective protection of ash log piles was reached with variants treated with four or nine lures of Sexowit. In relation to control infestation was reduced by 78.1% on 4-dispenser variant Sexowit and 88.9% on 9-dispenser variant Sexowit.

Control of Synanthedon (Aegeria) myopaeformis by Mating Disruption Using Sex Pheromone Dispensers in Northern Greece

In 3 successive years (1990-1992) polyethylene tube dispensers, each containing 50.5 mg synthetic sex pheromone of the apple clearwing moth, Synanthedon (Aegeria) myopaeformis Borkh., were placed at a density of 680 per ha, once a year, in two adjacent commercial apple orchards each I ha in size. The degree of confusion reached almost 100% by releasing about 6 mg/ha/h, whereas the number of mated females decreased by 72.86%, compared with the untreated orchard. In 1993, after 3 years of experiments, a reduction of up to 91% of empty pupal skins per tree was attained. The encouraging results, especially when taking into account the relatively small size of the orchards, opens opportunities for the integrated control of this apple insect pest under the conditions of Northern Greece.

Simultaneous control of Cydia molesta and Anarsia lineatella in peach orchards of Northern Greece by combining mating disruption and insecticide treatments

Trials were carried out in 1987 and 1988 on the combined control of oriental fruit moth (OFM), Cydia molesta (Busck), and peach twig borer (PTB), Anarsia lineatella (Zell), in peach orchards in Northern Greece with Isomate-M pheromone dispensers (mating disruption technique) and insecticides against OFM and PTB, respectively. One application of the Isomate-M at a rate of 1,000 units per ha, and one application of the insect growth inhibitor (IGI) hexaflumuron 5 EC (200 ml f.p,/hl) or two sprays of fluvalinate 25 AF (60 ml f.p./hl) during June provided satisfactory control of OFM and PTB. Total damage per tree in the trials reached 1.0-3.6%, versus 1.4-3.0% in the conventionally sprayed orchards, while in unsprayed control blocks it was 14.4-23k. These encouraging results open possibilities for the combined control of these peach insects in Northern Greece.

Control of Cydia molesta (Busck) by mating disruption using Isomate-M pheromone dispensers in Northern Greece

Trials were carried out in 1986 and 1987 with the mating disruption method for the control of oriental fruit moth (Cydia molesta Busck) in peaches of Northern Greece. One or two applications during April-September of the synthetic pheromone lsomate-M, at a rate of 1,000 units per ha, resulted in a 100% prevention of captures in pheromone traps in all trials, with fruit damage ranging from 0.1-2.0%. Damage in the conventionally sprayed treatments was 0.3-2.4% while infestation in the unsprayed plots reached 6-17%. The encouraging results, especially when taking into account the relatively small size of the orchards, opens opportunities for the integrated control of this peach insect pest under the condi­tions of Northern Greece.

The influence of evaporated pheromone upon the trapping of the spruce bark beetle – Ips typographus (L.) (Coleoptera: Curculionidae: Scolytinae) – Short communication

This article examines the relative efficacy of releasing a larger pheromone plume volume and the relative efficacy of the number of pheromone dispensers within baited traps in trapping the spruce bark beetle. Pheromone plume is released from a standard pheromone dispenser, and a higher volume of pheromone was provided by an increased number of pheromone dispensers. A field trial with 30 pheromone baited traps was conducted in 2013 that used three dispenser variants over ten replications. Ten traps were baited with one pheromone dispenser, ten with two dispensers and ten with three dispensers. The pheromone dispensers were placed according to EPPO standard PP1/152(4) in a fully randomized design. The highest trapping was achieved by the variant using three pheromone dispensers, and the lowest trapping was achieved by the two pheromone dispenser variant. There was no statistically significant difference between the three variants. The results suggest that the efficacy of pheromone traps cannot be increased solely through an increase in the number of pheromone dispensers.

Development of 2-phenylethanol plus acetic acid lures to monitor obliquebanded leafroller (Lepidoptera: Tortricidae) under mating disruption

We evaluated the effectiveness of 2-phenylethanol (PET) in combination with acetic acid (AA) as a binary lure for monitoring male and female obliquebanded leafroller, Choristoneura rosaceana (Harris). Studies were conducted in apple, Malus domestica Borkhausen, orchards treated with or without sex pheromone dispensers for mating disruption (MD). Open polypropylene vials, closed membrane cups, and rubber septa loaded with AA and/or PET in varying amounts were first evaluated in a series of trapping experiments. Membrane cups loaded with 800 mg of PET were as effective as 10-mg septa, but longer lasting, and were comparable to the open vials. A membrane cup AA lure was effective in tests, but further work is needed to increase its release rate and extend its activity. Catches of codling moth, Cydia pomonella (L.), and C. rosaceana were unaffected by combining PET with (E,E)-8,10-dodecadien-1-ol, the sex pheromone of codling moth, pear ester, (E,Z)-2,4-ethyl-decadienoate, and AA lures. Adding (E)-4,8-dimethyl-1,3,7-nonatriene to this blend to enhance codling moth catch, significantly reduced catches of C. rosaceana. PET+AA was a more attractive binary lure than AA plus phenylacetonitrile (PAN) for C. rosaceana. The addition of PET or PAN to traps already baited with the sex pheromone of C. rosaceana significantly reduced male catches. Traps baited with PET+AA placed in blocks not treated with MD caught significantly fewer C. rosaceana than traps baited with sex pheromone. In comparison, sex pheromone-baited traps in MD blocks caught ≤ 1 male moth per season which was significantly lower than total moth (> 10) or female moth (≥ 3) catch in these blocks with PET+AA. A high proportion (> 70%) of trapped females were mated in both untreated and MD-treated orchards. Further refinement of this binary, bisexual lure using membrane cup technology may allow the establishment of action thresholds and improve management timings for C. rosaceana.

The correlation between the changes in climate, the intensity of spruce decline and the abundance of of spruce bark beetles in 'Golija' Nature Park

The paper presents the results of the research on the correlation between changes in microclimate, the intensity of spruce decline and active abundance of its two economically most significant harmful insects-eight-toothed (Ips typographus) and six-toothed (Pityogenes chalcographus) spruce bark beetles (Coleoptera: Curculionidae) in Golija Nature Park whose pure and mixed conifer stands are dominated by spruce. The route method and ocular inspection were applied to study the presence and determine the intensity of spruce decline-both of individual trees and groups of trees in the management units of Dajićke planine, Kolješnica, Golija and Brusničke šume. Population dynamics of the two species of bark beetles and their active abundance were monitored by the method of trapping with barrier traps and the use of combined pheromone dispensers-PCIT Ecolure. Although the decline of individual conifer trees, primarily of spruce, had already been present in certain areas of these management units for several decades, it reached epidemic proportions due to extreme adverse climatic conditions in the period between 2011 and 2012 and culminated in 2015. A large number of physiologically weakened trees raised the population levels of secondary harmful insects and the number or the active abundance of the two investigated species of insects reached a peak in 2016. The inability to take appropriate and timely remedial measures in the areas under stricter protection regimes greatly contributed to this situation.