Testing mating disruption of the horse chestnut leafminer <Emphasis Type="Italic">Cameraria ohridella</Emphasis> (Lepidoptera: Gracillariidae) in field tents

Since the beginning of the invasion of the horse chestnut leafminer, Cameraria ohridella Deschka and Dimic 1986 (Lepidoptera: Gracillariidae), into Europe over 20 years ago the damage to white flowering horse chestnut trees, Aesculus hippocastanum L (Sapindales: Hippocastanaceae) has remained extensive. This study evaluates the possible use of pheromone mating disruption as a control option against the horse chestnut leafminer. The heterogeneous distribution of ornamental trees in parks and gardens requires a different approach to evaluate pest control than in homogeneous crop fields, orchards or plantations where mating disruption is usually applied. For this reason we set up field experiments with host trees of the same age and size in field tents with a defined number of leafminers in two different densities. In the first experiment the effective quantity of newly developed C. ohridella pheromone dispensers was tested by recapturing males using traps baited with virgin females. Ninety-five percent less males were captured if three or more dispensers were positioned at a 4 m radius around the outside of an experimental tent. This set up was then used in the second experiment where male and female leafminers were released into field tents in order to assess the effect of pheromone on the reduction of leaf mining damage. Surprisingly, the pheromone dispensers were found to have no effect on the number of leaf mines at either low or high leafminer densities. Mating sites of the horse chestnut leafminer, multiple matings and distribution of pheromone dispenser are discussed as possible factors influencing the outcome in this study.     

The effect of climate on radial growth of horse chestnut (<Emphasis Type="Italic">Aesculus hippocastanum</Emphasis> L.) in the Świętokrzyski National Park in central Poland

The objectives of this study were to construct a site tree-ring width chronology of horse chestnut (Aesculus hippocastanum L.) growing in a single locality situated in the Świȩtokrzyski National Park, and to determine its sensitivity to the two main climatic elements of air temperature and precipitation. Fifteen horse chestnut trees, growing on a moist site and not attacked by the leaf miner (Cameraria ohridella Deschka et Dimić), were selected for the study. Relationships between monthly values of air temperature, precipitation, and width of tree rings during 1932–2003 were analyzed, in addition to using bootstrapped response and correlation functions for single and multiple time intervals (the computer program DENDROCLIM2002 was used). High air temperature of the previous winter, as well as the air temperature of August of a given growing season positively affected the radial growth of horse chestnut. The cambium activity was also favored by ample precipitation in December preceding a given growing season. Excessive precipitation in August, which raised the existing high water table, had a negative effect on tree-ring width. The tree-ring chronology, elaborated for horse chestnut during this study, may be a local growth standard of this species. Thus, the model of climate–tree radial increment relationships may depend on characteristics of the locality where the trees are growing. Therefore, it would be advisable to undertake comparative studies.     

Estimating risks for spruce bark beetle (Ips typographus (L.)) damage using pheromone‐baited traps and trees

The risk for damage associated with spruce bark beetle attacks on living trees was estimated in 12 forest districts in the Nordic countries during three years. Pheromone‐baited traps and trees were used. Five groups of three traps were deployed annually on fresh spruce clear‐fellings in each district. The mean catches within districts and years ranged from 950 to 46000 beetles per trap group. The standard error averaged 15 % of the mean catch. One tree was baited annually at each of five other sites in each district. The mean number of trees colonized by Ips typographus in each district and year ranged from 0 to 5 per site. The standard error was high, averaging 44% of the mean. Inventories of tree mortality within the districts yielded values ranging from 0 to 150 killed trees per km of spruce forest edge. There was a strong linear correlation between mean catches in traps and log‐transformed tree mortality (r=0.82). The correlation between colonization success at tree‐baiting sites and tree mortality was weaker (r=0.59), owing to one deviant observation. The results indicate that pheromone traps and baited trees may be used to assess the risk for damage caused by Ips typographus.     

Season-long mating disruption of <Emphasis Type="Italic">Grapholita molesta</Emphasis> (Lepidoptera: Tortricidae) by one machine application of pheromone in wax drops (SPLAT-OFM)

A novel emulsified wax dispenser (SPLAT-OFM) of pheromone was evaluated in concert with a custom-built, tractor-mounted applicator, designed for fast application of dispensers for mating disruption of Oriental fruit moth, Grapholita molesta (Busck), in apple. The formulation consisted of microcrystalline wax emulsified in water. It was loaded with G. molesta pheromone (93:6:1 blend of (Z)-8-dodecen-1-yl-acetate:(E)-8-dodecen-1-yl-acetate:(Z)-8-dodecen-1-ol) at 10% by weight. The hydraulically driven applicator dispensed the wax formulation as discrete particles from a rotating double-orifice distributor positioned directly above the tree canopy. Wax-drop size averaged (±SEM) 0.38 ± 0.16 g and 4.3 ± 0.5 drops adhered per tree. Following a single mechanized application of SPLAT-OFM on 24 April at 8 ml per tree (1.6 kg/ha) to 0.8 ha blocks of apple, male G. molesta orientation to optimally attractive pheromone traps was disrupted by 98% relative to untreated control plots for the whole season. Furthermore, on 17 weekly deployments of tethered virgin females (1,016 females deployed and 732 recovered for dissection) throughout the season, no mating was detected in SPLAT-OFM-treated blocks, while mating in control blocks averaged 27%. During the first 17 days following deployment in sticky traps, SPLAT-OFM drops attracted ca. 1/46th of the number of male G. molesta attracted to optimized synthetic lures. However, following 17 days of field aging, SPLAT-OFM drops became equally attractive to optimized synthetic lures for the remainder of the season. The release rate of pheromone from wax drops 0–14 and 15–76 days following deployment averaged 21.4 and 5.3 μg/h, respectively. The trapping and release rate data were consistent with competitive attraction as the mechanism mediating disruption. Shoot injury following the first moth generation was sevenfold less in SPLAT-OFM treated blocks compared with controls and fruit injury at the end of the season in treated blocks was approximately half of that recorded in controls.     

Pheromonfallen zur Bestimmung des Apfelwicklerfluges

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

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Summary Determination of the flight of tortricids in orchards by help of pheromone baited sticky traps Since 1971 in Southern Germany pheromone baited sticky traps in orchards were used for prognosis of Tortricids. The techniques of the traps, their use and also the results of experiments with codling moth peromones from 1971 to 1973 were given in relation to catches of ligt traps. Synthetic pheromones call better and catch more moths than natural sexual pheromones of living virgine females. The pheromone baited traps allow to determine the local and temporal flight curve of codling moth in orchards. The method is now ready to be introduced for practical use.

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Nach einem Vortrag, gehalten auf der 39. Deutschen Pflanzenschutztagung in Stuttgart, 1.–5. 10. 73. — Die Arbeiten werden vom Bundesministerium für Ern?hrung, Landwirtschaft und Forsten in Bonn unterstüzt.     

Comparison of seasonal responses ofHylobius abietis (L.) (Col., Curculionidae) to chemical and natural lures in baited pitfall traps

Differences in catches ofHylobius abietis (L.) adults in baited pitfall traps with chemical (alpha-pinene, ethanol, water) and natural (spruce billets, water) lures were found not in the over-all number of trapped adult weevils, but in the per cent occurrence and number of old and young beetles in individual periods of the season.     

Effects of accumulate dead and alive insects in trap on the capture ofTribolium castaneum (herbst)

In the trapping ofTribolium castaneum (Herbst), the activity of traps baited or not baited with aggregation pheromone 4,8-dimethyldecanal is influenced by the presence in the traps of accumulate specimens trapped. This fact has been observed both in trap containing alive or dead specimens. Interactions in the different substances produced by adults of Red Flour Beetle during their communication relationship are involved in this behaviour.The results obtained in the trials suggests that the presence of alive insects in traps is attractive for other free specimens, but under conditions of overcrowding quinone produced by them regulate population density by counteracting the effect of the aggregation pheromone, causing the insects to disperse or suppressing aggregation behaviour.The presence of dead insects in the traps, baited or not baited with pheromone, can be repellent for other free specimens ofT. castaneum, probably related to the presence of a residual alarm pheromone produced by the specimens before of death.With 10 figures and 3 tables     

Seasonal variability of sex-ratio in<Emphasis Type="Italic"> Ips typographus</Emphasis> (L.) pheromone traps in a multivoltine population in the Southern Alps

The aim of the study was to monitor the seasonal variation in the sex-specific responses of Ips typographus to a commercial pheromone in relation to the two generations per year occurring in the Southern Alps. The study was carried out over 2 years (2000–2001). Each year, 15 Theysohn traps were baited with Pheroprax. Traps were emptied weekly and the number of beetles determined. In the same forest each year, three spruce logs were set up at the beginning of spring for natural colonisation by Ips typographus and then put in breeding boxes. All adults emerging from the logs or found in the traps were counted and a subsample sexed by genital extraction. Spring captures were always higher than summer captures (second generation). Similarly, the proportion of trapped males was always higher in spring than in summer. Except in the first and second week, the number of females was higher than males. During the first 3 weeks of monitoring, the number of trapped males dropped from above 50 to about 30%. Thereafter, the sex ratio was constant over time, about 33% males. In contrast to trap catches, about 50% of adults emerging from the breeding logs were males. The low proportion of males in traps depends both on discrimination (they avoid strong sources of male pheromone) and on differential mortality of the sex over time. As the pioneer beetles in I. typographus are males, their number is highest in the first part of the flight period when they search for suitable host trees. Such a search can be lethal for several males, decreasing the sex ratio.     

Factors affecting field performance of pheromone traps for tobacco beetle, <Emphasis Type="Italic">Lasioderma serricorne</Emphasis>, and tobacco moth, <Emphasis Type="Italic">Ephestia elutella</Emphasis>

Tobacco beetle, Lasioderma serricorne (F.) (Coleoptera: Anobiidae), is one of the most serious insect pests of stored tobacco, and traps baited with the female-produced sex pheromone, serricornin, are used for monitoring the pest. In two trapping experiments carried out in tobacco warehouses in Greece, two commercially available trap and lure systems for L. serricorne were found to be equally effective in terms of the numbers of beetles trapped. In contrast to previous reports, anhydroserricornin was unattractive and lures containing serricornin and anhydroserricornin were less attractive than lures containing serricornin only. The sex pheromone of the other main insect pest of tobacco, Ephestia elutella (Hübner) (Lepidoptera: Pyralidae), could be added to the lures without affecting the attractiveness of either pheromone to their respective species. Lures remained attractive for at least 4 weeks under field conditions, and, in laboratory tests, release of pheromone could still be detected after 30 days at 27 °C. The stereoisomeric composition of the serricornin in the two commercial lures was similar with high proportions of the attractive (4S,6S,7S)-isomer. The proportion of the (4S,6S,7R)-isomer was low, and this is known to reduce the attractiveness.     

Appearance and migration of the horse-chestnut leafminer Cameraria ohridella in relation to city size and leaf-raking, using the example of two cities in Western Poland

Possible differences in the size and dynamics of the appearance of particular generations of Cameraria ohridella were studied at two city sites of different size and character. The differences in the degree of infestation of Aesculus hippocastanum by the horse chestnut leafminer in the two towns are interpreted as a result of the differences in the size of food resources. The greater degree of infestation of trees in Mosina relative to trees in Pozna is most probably a result of the difficulty of aerial dispersion and thereby much stronger competition for food. This conclusion confirms a positive correlation of the distance between localities with the degree of tree infestation in a small town and the lack of such a correlation in a big city. The presence of refuges in the city outskirts at which no raking and removal of leaves is performed does not seem to have a significant effect on the degree of horse chestnut infestation in the centre.     

Acute spread in France of an invasive pest, the horse chestnut leafminer Cameraria ohridella Deschka & Dimic (Lep., Gracillariidae)

The horse chestnut leafminer, Cameraria ohridella Deschka & Dimic (Lepidoptera, Gracillariidae) spread over the last 10 years from central Europe to western Europe and was observed for the first time in 2000 in the east of France and near Paris. This study presents the results of surveys carried out in France in 2001 to investigate the distribution and infestation level of the leafminer. One year after its first discovery, the moth was present in a large part of the country and for the first time has been observed in Paris. The spread of the moth is due mainly to natural dispersal and to passive dispersal by human activities.     

Zur Wirkung von Sexualpheromonen der Kartoffelmotte,Phtorimaea operculella Zeller (Lepid., Gelechiidae) im Vergleich mit verschiedenen Lichtfallen

A comparison, was made with two butane light traps and an electrical light trap. Of the trapping techniques tested, hightest moth catches were obtained with water pans baited with rubber caps impregnated with the mixture of the pheromone. This sexual trapping appears as the best procedure to use for agricultural warnings, to check the first flight.     

Chemical ecology of <Emphasis Type="Italic">Halyomorpha halys</Emphasis>: discoveries and applications

There have been notable and significant advances in elucidating the chemical ecology of the invasive Halyomorpha halys (Hemiptera: Pentatomidae), brown marmorated stink bug. This highly destructive and polyphagous pest is originally from Korea, China, and Japan, but was accidentally introduced into North America and Europe. Prior to its invasion into these regions, little was known about its chemical ecology. However, since then, researchers have identified and synthesized its aggregation pheromone, documented its synergism with the pheromone of another Asian stink bug, Plautia stali, developed monitoring traps of various designs, and lures with reliable attractants have become commercially available. Furthermore, plant volatiles have been shown to have attractive, neutral, and repellent effects on attraction and retention of H. halys, and H. halys-derived volatiles have been shown to play a role in recruiting natural enemies. Finally, management strategies based on pheromone-based technology have been evaluated, including insecticide applications based on a cumulative threshold of adult captures in pheromone-baited traps, and the use of intensively baited trees in an attract-and-kill strategy to manage this pest. This review summarizes the available literature on the chemical ecology of H. halys and concludes with several research areas that should be explored in future research.     

Test von Monoterpenen als Zusatz zu Pheroprax® bzw. Chalcoprax® in Pheromonfallen zum Fang des Buchdruckers,Ips typographus L. bzw. des Kupferstechers,Pityogenes chalcographus L. (Col., Scolytidae)

Experiments on monoterpenes in combination with Pheroprax^® and Chalcoprax^® in pheromone traps for catching the bark beetlesIps typographus L. andPityogenes chalcographus L. (Col., Scolytidae) It is highly evident that monoterpenes of the host tree serve as olfactory stimulants for “pioneer-beetles” colonizing first a tree before any bark-beetle-produced aggregation pheromones can lure those beetles to the host. The findings ofRedemann (1993) about a significant increase of spruce engraver catches by addition of both (?)-alpha-pinen and (+)-limonen simultaneously to pheroprax-baited bark beetle traps (Pheroprax^R being the aggregation pheromone ofIps typographus) induced us to conduct field experiments testing the same host volatiles in comparable bark beetle traps baited with either Pheroprax^® or Chalcoprax^® (aggregation pheromone ofPityogenes chalcographus). Despite we used methods considering the influence of place and time on the bark beetle flight activities, in 3 experiments with 30 repetitions in total no monoterpene-induced enhancement oftypographus-catches could be found; the same was true withP. chalcographus (2 experiments, 18 repetitions in total). With respect to the important role of host volatiles also from a practical point of view, it is strongly recommended to repeat experiments like these under different conditions to reveal the reasons of the different findings.     

Occurrence of common phyllosphere fungi of horse-chestnut (Aesculus hippocastanum) is unrelated to degree of damage by leafminer (Cameraria ohridella)

The horse chestnut leaf-miner (Cameraria ohridella Deschka & Dimi?, Lepidoptera, Gracillariidae) is an invasive pest causing extensive damage to leaves of the horse-chestnut (Aesculus hippocastanum L.) in Europe. In Lithuania, C. ohridella invaded in 2002 causing wilting, browning and premature fall of A. hippocastanum leaves. The aim was to get a better understanding of possible linkages between foliar fungal communities and leaf-miner damage in A. hippocastanum. Leaves of A. hippocastanum, differentially damaged by C. ohridella, were collected in 10 sites in Lithuania. The fungal communities were described through DNA isolation and amplification using an ITS rRNA marker and Ion Torrent-sequencing. Clustering of 214,897 high-quality sequences resulted in 1017 non-singleton fungal taxa, among which Aureobasidium pullulans (28.2% of all fungal sequences), Endoconidioma populi (27.7%), Phoma fungicola (11.3%), Cladosporium ramotenellum (7.6%) and Cryptococcus sp. 2185_4 (5.0%) were most common. Correspondence analysis showed that fungal communities from heavily and slightly damaged leaves were largely intermingled, showing that in both types of samples fungal communities were similar. In conclusion, the study demonstrated that the phyllosphere of A. hippocastanum is inhabited by a high diversity of fungal species, the majority of which constitute generalist endophytes, epiphytes and saprotrophic fungi. The occurrence of common phyllosphere fungi was unrelated to the degree of damage by C. ohridella.     

Aerially applied verbenone-releasing laminated flakes protect Pinus contorta stands from attack by Dendroctonus ponderosae in California and Idaho

We tested a new formulation of verbenone, an antiaggregation pheromone of the mountain pine beetle (Dendroctonus ponderosae Hopkins) (Coleoptera: Curculionidae: Scolytinae), for area-wide protection of lodgepole pine (Pinus contorta Douglas ex Loudon) stands in the western United States. Helicopter applications of verbenone-releasing laminated flakes were made at the rate of 370 g of active ingredient/ha to two sites, one in California and one in Idaho, during summer 2005. Each site consisted of five 20.23-ha treated plots and five matching 20.23-ha untreated plots. We assessed D. ponderosae flight into study plots using traps baited with aggregation pheromones and we tallied D. ponderosae attack rates on P. contorta trees in treated and control plots before and after application. There were no significant differences between numbers of D. ponderosae trapped on treated and control plots. However, a significantly smaller proportion of P. contorta trees was attacked in treated plots than in control plots at both sites; the attack rate in untreated stands was roughly three times that of treated stands in both California and Idaho, even at this low application rate. Furthermore, attack rate in 2004 was a significant explanatory variable for the response in 2005 regardless of treatment in both California and Idaho. There was no significant treatment effect at either site on attraction of Temnochila chlorodia (Coleoptera: Trogositidae) Mannerheim, a key predator of D. ponderosae, to the prey aggregation pheromone.     

Attraction of <Emphasis Type="Italic">Lygus rugulipennis</Emphasis> and <Emphasis Type="Italic">Adelphocoris lineolatus</Emphasis> to synthetic floral odour compounds in field experiments in Hungary

Field experiments were carried out to ascertain whether synthetic floral odour compounds were attractive for two pest bug species. The European tarnished plant bug (Lygus rugulipennis Poppius) has been reported to damage various crops (e.g. strawberry, sugarbeet, alfalfa, cucumber), and the alfalfa plant bug (Adelphocoris lineolatus (Goeze)) is considered as a pest of alfalfa and Bt-cotton. In our field tests, traps baited with phenylacetaldehyde caught significantly more L. rugulipennis than unbaited traps. In addition, A. lineolatus was also attracted to phenylacetaldehyde-baited traps. When testing other, EAG active compounds, (E)-cinnamaldehyde attracted A. lineolatus as well. This compound was also attractive for L. rugulipennis, however, to a lesser extent than phenylacetaldehyde. When the two compounds were presented in combination, no synergistic or inhibitory effect was detected in either species. By attracting both sexes of both species, these new attractants may prove to be useful and provide the basis for further development of new lures for agricultural use.     

Challenges of pheromone-based mating disruption of <Emphasis Type="Italic">Cydia strobilella</Emphasis> and <Emphasis Type="Italic">Dioryctria abietella</Emphasis> in spruce seed orchards

Seed orchards function as the primary source of high-quality seeds for reforestation in many European countries, but their seed yields can be severely reduced due to seed- and cone-feeding insects. We evaluated various parameters of pheromone-based mating disruption for control of the moths Cydia strobilella and Dioryctria abietella, which are major pests in European Picea abies seed orchards. We applied different types of pheromone dispensers (rubber septa or wax droplets) at different densities and heights, and with different amounts of active components, covering whole orchards or part of an orchard. The efficacy of the treatment was evaluated by analysing male captures in pheromone-baited assessment traps, and presence of larvae in cones. A dramatic decrease (94–100%) in capture of males in traps occurred in all pheromone-treated plots compared to control plots for both moth species. In contrast, a subsequent reduction in larval numbers in cones was only achieved when wax droplets were used as the dispensing formulation at high density and at the highest pheromone dose tested, and only in half of the trials for each pest species. Electrophysiological recordings using antennae of male C. strobilella indicated elevated pheromone concentrations in a treated plot versus a control plot. Our results show that mating disruption has potential to reduce cone damage in spruce seed orchards caused by C. strobilella and D. abietella, but optimisation of the technique is required to achieve consistent and efficient population suppression of these pests.     

The effect of grape vine cultivars on <Emphasis Type="Italic">Lobesia botrana</Emphasis> (Lepidoptera: Tortricidae) population levels

The European vine moth Lobesia botrana Denis & Schiff. (Lepidoptera: Tortricidae) is a key pest in the vineyards of Israel and Europe. Traps baited with the female sex pheromone are commonly used to monitor the pest population. However, the role of the vine cultivars on monitoring the moth population using pheromone-baited traps was not yet studied. The present study aimed to identify the effect of grape cultivars on L. botrana adult distribution patterns in the field, in order to achieve a better understanding of the monitored data in respect to male and female’s host preference. The 3-year study in commercial vineyards used four cultivars: Carignan, Emerald Riesling, French Colombard, and Cabernet Sauvignon. The moth population of each generation was estimated from male counts in pheromone traps; three generations were observed in all experimental orchards, each year. Female host choice was studied by monitoring freshly deposited eggs and newly hatched larvae on vines. The study showed a significant effect of cultivar on numbers of trapped males in most years, and a cultivar effect on female host choice. For both males and females and for all phenological stages of the grapes, Carignan and French Colombard attracted the most and Cabernet Sauvignon the fewest specimens. The results show that cultivar blend within the vineyard can affect the distribution pattern of the pest. Knowledge of the expected choice of the female moth, and of the timing of its decision could lead to an improved monitoring system, with the preferred cultivar as an indicator.     

First detection of Bursaphelenchus mucronatus (Nematoda: Aphelenchoididae) on Monochamus sutor (Coleoptera: Cerambycidae) in Romania

As a result of the detection of the pinewood nematode Bursaphelenchus xylophilus in Portugal, and its subsequent spread to Spain, intense surveys were conducted to screen for the presence of Bursaphelenchus species in Romania. Herein, we report recent surveys of insects potentially vectoring Bursaphelenchus species collected using trap trees or pheromone‐baited traps placed in the forest. Trap felled spruce trees (Picea abies) and pheromone‐baited traps were installed in six different counties in Romania (Bra?ov, Sibiu, Suceava, Hunedoara, Timi? and Dâmbovi?a). Ten different species of insects distributed among Curculionidae and Cerambycidae were obtained. Nematodes were extracted from insects and observed to validate the presence of Bursaphelenchus specimens. One female identified as Monochamus sutor was the only specimen carrying nematodes in the genus Bursaphelenchus. Nematodes were identified as B. mucronatus based on morphological and molecular features. This is the first detection and report of natural spread of B. mucronatus in Romania. The absence of B. xylophilus was confirmed in the areas of Romania surveyed in this work.