For the first time soil solarization was investigated in Croatia both in the field and in the greenhouse in 1991, 1992, 1993 and 1994. For two months (July and August), the soil was mulched with transparent polyethylene (PE) sheets of 0.015 or 0.050 mm thickness. Soil temperatures at depths of 5, 10 and 20 cm were recorded daily. In order to assess nematode population densities, soil samples were analysed before mulching and at the end of the mulching treatment. The results of these experiments showed that soil solarization drastically reduced the population of plant-parasitic nematodes (Meloidogyne, Pratylenchus, Paratylenchus, Tylenchus, Tylenchorhynchus spp.) by about 97–100 % at a depth of 10 cm and 92–97 % at a depth of 20 cm in the field, while in the greenhouse, the population of plant-parasitic nematodes was reduced by about 89–100 % at a depth of 10 cm and 98–100 % at a depth of 20 cm.In the same experiments, the population of saprophytic nematodes in the field was reduced by about 86–90 % at a depth of 10 cm and 72–89 % at a depth of 20 cm. In the greenhouse, the population of saprophytic nematodes was reduced by about 87–97 % at a depth of 10 cm and 87–93 % at a depth of 20 cm. This data shows that soil solarization was less effective in the control of saprophytic nematodes, which is considered to be an advantage.

AbstractStrategies targeting the biological control of the cherry bark tortrix (=CBT), Enarmonia formosana (Scopoli) in North America have also included the search for potentially useful native hymenopterous parasitoids of the pest in Europe. The search for such agents undertaken in the central‐east Europe (Czech Republic, Slovak Republic, Hungary) resulted in determination of several ichneumonid species (Campoplex cf. dubitator Horst., Liotryphon sp., Lissonotus sp., Pimpla spuria (Grav.), Pimpla turionellae (L.), and some others, and a braconid (Apanteles britannicus Wilk.) in 2001–2002.

AbstractThe relationship between Xenorhabdus nematophilus and Photorhabdus luminescens, the bacterial symbionts of the entomopathogenic nematodes Steinernema carpocapsae and Heterorhabditis bacteriophora, against the diamondback moth, P. xylostella (L.), pupae showed the pathogenic capability of P. luminescens to be over that of X. nematophilus. They gave 60 and 40 % mortality with LC50 values of 5 × 104 and 5.5 × 105 cells/ml, respectively.The number of bacterial cells influences the rate of killing the pupae of P. xylostella and a direct correlation between mortality of the pupae, percentage of deformed adults and the spraying dose with significant differences were observed. An inverse correlation found between the no. of eggs laid/female, percentage of hatching, adult survival and the spraying dose. These bacterial effects have been attributed to different toxic bacterial enzymes which damage the haemocytes and inhibit activation of the humoral immune system of the insect.

AbstractWe describe a series of experiments on the protection of Norway spruce (Picea abies (L.) Karst.) logs and standing trees against Ips typographus L. (Coleoptera: Scolytidae). The tested protective materials were applied 1) at point sources and 2) area‐covering using zeolite‐based dispensers. We performed 11 terrestrial and one aerial application (using a helicopter) between 1992 and 2001. We gradually replaced polyethylene‐bag verbenone dispensers by composite dispensers releasing verbenone and non‐host volatiles (NHV: green leaf volatiles, trans‐conophthorin, and C8‐alcohols). Many experiments did not give statistically significant results, due to the low number of true replicates and the spatial heterogeneity of beetle attacks. The protection of horizontal objects like logs or lying trees with anti‐attractants was not always successful. In the future, positive results can be expected with an area covering spray applied by zeolite dispensers containing mixtures of verbenone and NHV. A similar approach could probably be used in aerial spraying of anti‐attractants.We have succeeded in our attempt to protect zones of standing spruce trees from I. typographus attacks. We used dispensers with a combination of verbenone and a full blend of NHV compounds. The protection is not complete, but in both 2000 and 2001, the treatment significantly decreased the probability of the insect attack on trees by 60–80 %.

AbstractVolatiles from newly cut branches with needles of Pinus sylvestris L. were collected with headspace sampling technique, and then identified and quantified by combined gas chromatographic‐mass spectrometry (GC‐MS). The response of antennae of the female pine processionary moth, Thaumetopoea pityocampa, to these volatiles was recorded by coupled gas chromatographic‐electroantennographic detection (GC‐EAD). Surprisingly, the most common and major monoterpene hydrocarbons (MT), α‐pinene, 3‐carene, and β‐pinene were antennally inactive. Female antennae responded strongly only to four minor MT components, myrcene, β‐phellandrene, trans‐β‐ocimene, and terpinolene. Weaker, but repeatable responses were also found to limonene, cis‐β‐ocimene, and γ‐terpinene. Further EAD recordings with two synthetic MT mixtures supported our findings from the natural material. When separating the two enantiomers of limonene by running different synthetic MT mixtures, the EAD response was found only to the(−)‐enantiomer, but not to the opposite (+)‐enantiomer. EAD‐responses were also found to some less volatile compounds, such as sesquiterpenes (SqT), active at ng‐levels. The sensitivity and specificity of the antenna to a select number of active host MTs and SqTs suggest that these play a role in the host selection process of T. pityocampa females.

AbstractAn aphid and virus survey was conducted from 1993 and 1999 on the eastern lowlands in Hungary. Aphid flight was monitored with two yellow pan traps placed on the edge and in the middle of seed potato fields. From 1993 and 1997, aphid flight was monitored with a Rothamsted type suction trap. The aphid and virus survey was continued in four different regions of Hungary in 2000. Aphid flight activity recorded by the suction trap and the yellow pan traps was different. Cumulative vector intensity based on yellow pan trap catches revealed a greater variation between years than among the different locations. In 4 years out of 8, aphid flight was less intensive and quality seed potato was harvested regardless of the production site. Cumulative vector intensity is a good means to forecast the time of haulm destruction in seed potatoes.

AbstractThe predatory mite Typhlodromus pyri Scheuten (Acari, Phytoseiidae) has been reported as an important predator of the European red mite, Panonychus ulmi (Koch) (Acari, Tetranychidae) in apple culture and vineyards at below 25 °C. However, sufficient biological data was lacking on its efficiency at temperatures above 25 °C. Therefore, the purpose of the present laboratory work was to obtain experimental data on prey consumption during development as well as longevity and reproduction of T. pyri on apple leaf discs and in Plexiglas cells at constant temperatures of 25 ± 2 °C and 30 ± 2 °C with P. ulmi as prey.The results showed that mean daily and total prey consumption by both the nymphs and adults of T. pyri decreased significantly on both the arenas as the temperature was increased from 25 °C to 30 °C, whereby adult prey consumption, both mean daily and total, was higher than that of nymphs. Prey consumption by both the nymphs and adults was significantly higher in the Plexiglas cells than on the leaf discs at both temperatures. Mean total prey consumption during nymphal development was 16.1 (♀♀) and 12.8 (♂♂) at 25 °C compared to 7.0 (♀♀) and 5.8 (♂♂) preys at 30 °C on the apple leaf discs and 46.0 (♀♀) and 38.5 (♂♂) at 25 °C compared to 25.2 (♀♀) and 20.3 (♂♂) preys at 30 °C in the Plexiglas cells. Mean duration of nymphal development was similar for the two sexes at the same temperature, but it was longer at 25 °C than at 30 °C. It was 6.0 and 4.0 days on the apple leaf discs while 7.0 and 6.0 days in the Plexiglas cells at 25 °C and 30 °C, respectively. Mean daily and total prey consumption by both male and female adults also decreased with the increasing temperature, whereby the females consumed more than double the mean total number of prey than the males on both the arenas of observation and at both temperatures: 355.4 versus 149.7 preys at 25 °C and 192.2 versus 85.6 preys at 30 °C on the leaf discs and 826.8 versus 374.5 preys at 25 °C and 488.9 versus 187.9 preys at 30 °C in the Plexiglas cells. Longevity of the females was longer than males on both arenas and at both temperatures and it was longer at 25 °C than at 30 °C. Mean total longevity on the apple leaf discs was 68.3 (♀♀) and 50.8 (♂♂) days at 25 °C compared to 52.5 (♀♀) and 36.8 (♂♂) days at 30 °C, while in the Plexiglas cells it was 91.0 (♀♀) and 65.8 (♂♂) days at 25 °C compared to 75.3 (♀♀) and 48.5 (♂♂) days at 30 °C. Reproduction in females also decreased significantly with increasing temperature. It decreased from 62.0 to 39.0 eggs/female on the leaf discs and 75.0 to 47.1 eggs/female in the Plexiglas cells. The females laid significantly higher numbers of eggs at both temperatures in the Plexiglas cells than on the leaf discs. Oviposition period in females was 30 days at 25 °C on both the arenas, while at 30 °C it was 26 days on the apple leaf discs and 27 days in the Plexiglas cells.

AbstractThis paper presents the results of a research project concerning bark beetle populations in Norway spruce stands managed under a nature protection regime in national parks in Tatra Mountains in Poland and Slovakia. The preliminary data on bark beetle occurrence and related selected stand characteristics are presented. The dynamics of a bark beetle outbreak that occurred from 1994–97 in the stands localized on both sides of the state border and in various nature protection regimes is analyzed retrospectively. The data concerning the tree/stand characteristics, i.e. DBH and increment of trees are discussed in relation to its potential role in the mechanism for the spread of bark beetle populations. The patterns of the spatial distribution of trees attacked during the research period (1999–2001) are described.

AbstractThe side effects of the neonicotinyl compound thiamethoxam on the brood of bumble bees (Bombus terrestris L.) were investigated on tomatoes in plastic tunnels and glasshouses.Preceeding trials had revealed a strong contact and stomach activity of the compound by foliar application. A decisive improvement was obtained by replacing the foliar by drip irrigation of thiamethoxam at rates between 150 and 161 g ai/ha. The mortality figures of all bumble bee stages dropped to the level in the untreated control. No dead bumble bees were found in the thiamethoxam treated tunnels/glasshouses on the ground.Thiamethoxam could be rated as being harmless to bumble bees with a single application through the irrigation system. No spilling of this compound during the application should occur to avoid intoxication of adult bumble bees by oral uptake or contact contamination during the cleaning process. If multiple applications via the irrigation system or under any hydroponic growing conditions is considered, further sequential testing of this mode of use is recommended.

Abstract Canningia tomici sp. n. (Microsporidia, Unikaryonidae) infects the midgut epithelium, the gut muscules, Malpighian tubules, connective tissues, adipose tissues and the gonads of the pine shoot beetle, Tomicus piniperda (L.) (Coleoptera, Scolytidae). The infection is present in populations of Tomicus piniperda in Europe and in the United States. Uninucleate oval single spores occur in two sizes: 2.8 ± 0.4 × 1.4 ± 0.4 μm and 3.8 ± 0.3 × 2.0 ± 0.2 μm. The polar filament of this microsporidium is fixed subapically in a flat anchoring disc. The thick posterior lamellae of the binary polaroplast are asymmetric due to the lateral fixation of the polar filament.