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We 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 %.

The development of the red palm weevil, Rhynchophorus ferrugineus (Olivier) was investigated on a newly developed semiartificial diet as compared with two natural diets namely sugarcane stem and banana fruit. The weevil was successfully maintained on these diets and duration of the life cycle for males and females, respectively were 164.97 and 194.61 days on the semiartificial diet, 192.5 and 186.5 days on banana, and 172.00 and 170.00 days on sugarcane. The average egg production per female was shown to be significantly higher on the semiartificial diet, being 184.00 ± 18.68 eggs compared with an average of 125.00 ± 11.97 and 133.00 ± 15.21 eggs on banana and sugarcane, respectively. The fertility ranged between 94 – 100 % in those eggs deposited by females previously reared on the tested diets. The developed semiartificial diet was shown to be suitable for maintaining laboratory colonies of the red palm weevil, and it can substitute natural diets.

The utilization of olfactory responses of predators and ­parasitoids to the allelochemicals emitted by phytophagous arthropods and their host plants is becoming more important in biological pest control. The effects of three weed ­species, i. e. wormwood Artemisia vulgaris L., tansy Tanacetum vulgare L. and stinging nettle Urtica dioica L., which were planted as accompanying vegetations into a lettuce field, were examined for the predatory species Coccinella septempunctata L., Adalia bipunctata (L.), Propylea quatuordecimpunctata (L.) (Coleoptera, Coccinellidae) and Chrysoperla carnea (Steph.) (Neuroptera, Chrysopidae), as well as for aphids during the summer of 2000. The presence of weeds significantly increased the density of adults and larvae of the predators on the lettuce plants in relation to the control (lettuce field without weeds). However, the differences remained smaller for eggs and pupae. C. septempunctata tended to be the most abundant species, followed by P. quatuordecimpunctata. Remarkable differences among the attractiveness levels of the weeds in the 3 treatments were not observed. The increased populations of predators were accompanied by significantly reduced infestation rates with aphids in the treatments in relation to the control. Myzus persicae Sulzer was in general the most abundant aphid species followed by Nasonovia ribisnigri Mosley and Macrosiphum euphorbiae Thomas. The results of the present study are discussed with respect to the management of agroecosystems and the use of weeds in biological control.

The external and internal morphological characteristics of the predator Rhyzobius lophanthae Blaisdell (Coleoptera, Coccinellidae) were studied. The head, antenna, thorax elytra, hind wings, legs and abdomen are described. The adult has an average length of about 2.5 mm and width of 1.8 mm. The flagellum of the antenna consists of 9 segments. The whole surface of thorax and elytra is covered by setae. The tarsus of the 3 legs is 3‐segmented. An external morphological difference between male and female is the outline of the 5^th sternite. The alimentary canal, the central nervous system, and the reproductive system of both male and female are also described. The testes consist of 10 follicles and the ovaries of 10 ovarioles. The life cycle of R. lophanthae was studied by rearing the predator on the diaspidid Chrysomphalus aonidum (Linnaeus). The duration of the development of the embryo, 1^st, 2^nd, 3^rd, 4^th larval instars, pupa and preoviposition period of adults were measured at 15, 20, 25 and 30 °C.

130 kg of acorns of Common Oak (Quercus robur L.) were distributed on an area of 1.44 ha in an oak forest near Zagreb (Croatia), where acorns were lacking. The influence of this surplus of food on the development of mice and voles was observed from September 1999 till February 2000 on the experimental plot and on an untreated control area before and after offering the acorns. The Redbacked Vole Clethrionomys glareolus was the most abundant and dominant species in both observed areas. After distribution of the acorns, all species of mice, e. g. the Yellownecked Fieldmouse Apodemus flavicollis, the Longtailed Fieldmouse A. sylvaticus, and the Striped Field Mouse A. agrarius, increased up to 4 times in number on the area treated with a surplus of acorns. On the same area, however, all species of voles, e. g. the Redbacked Vole C. glareolus, the Field Vole Microtus agrestis, and the Common Vole M. arvalis, decreased. The numbers of captured and recaptured rodents before and after offering acorns on the treated and the untreated control area were compared by statistical analysis (Chi²‐test). The results show how food can influence the competitive relations between mice and voles.

The possibility for the combined control of Ophiostoma novo‐ulmi and Scolytus multistriatus was tested in Italy. Two elm clones [U. pumila×U. minor (clone B) and U. glabra var. pendula grafted onto U. pumila×U. minor pollards (clone A)] were treated by stem injection of different blend or concentrations of fungicides and insecticides. Then, adults of S. multistriatus, either loaded with spores of two isolates of O. novo‐ulmi (H328 and 182) or provided of their natural load of conidia, were forced to feed in twig crotches of the treated trees. After 48 hours all insects were checked (dead or alive). One month later, the same twigs were cut off and brought to the laboratory. From each twig, three discs almost 1 mm thick were then taken (0, 3 and 6 cm over the point where the insect fed). The wood discs were inoculated in selective substrate and stored until the development of O. novo‐ulmi colonies. All thesis containing insecticides give good results against S. multistriatus. Similarly, all thesis containing fungicides show a good fungus control independently from the fungal isolated. The percentage of fungal transmission obtained from insects carrying the natural load of conidia was lower than percentages obtained from beetles artificially loaded. Both beetle sex and position on the foliage never influence insect mortality or O. novo‐ulmi infection. The best results were obtained injecting the Carbendazim + Acephate blend in the clone A. High chemical concentrations did not improve the general results.