Lokken en bestrijden van de taxuskever : Eindrapportage

Bestrijding van taxuskever is een groot knelpunt in de boomkwekerij. Eerder onderzoek heeft een lokval voor taxuskever opgeleverd. Dit vervolgproject bestond uit verdere beproeving van de lokval, tezamen met de lokstof. Aan de PT-financiering was medefinanciering van een fabrikant als voorwaarde gesteld

Female-induced increase of host-plant volatiles enhance specific attraction of aphid male Dysaphis plantaginea (Homoptera: Aphididae) to the sex pheromone

All aphid species studied so far share the same sex pheromone components, nepetalactol and nepetalactone. Variation by different enantiomers and blends of the two components released by different aphid species are limited and can only partially explain species-specific attraction of males to females. While some host-plant odours are known to enhance specific attraction of aphid species, herbivore-induced plant volatiles that synergise attractiveness to the sex pheromone are unknown. Here, we demonstrate that for the host-alternating rosy apple aphid (Dysaphis plantaginea (Passerini)) specificity of attraction of males to females is triggered by female-induced tree odours in combination with a 1:8 ratio of (4aS,7S,7aR)-nepetalactone and (1R,4aS,7S,7aR)-nepetalactol. Female aphid infestation induces increased release of four esters (hexyl butyrate, (E)-2-hexenyl butyrate, (Z)-3-hexenyl 3-methylbutyrate and hexyl 2-methylbutyrate) from apple leaves. Two different combinations of three esters applied in a 1:1:1 ratio increase the number of male D. plantaginea and decrease the number of other aphid species caught in water traps in the presence of the pheromone components. The ester blend alone was not attractive. Combination of the pheromone blend with each single ester was not increasing attraction of male D. plantaginea. The demonstration that sexual aphid species use herbivore-induced plant volatiles as a species-specific attractant for mate finding adds a new dimension to our understanding of insect species using or manipulating chemical cues of host plants for orientatio

Parfum fatale voor de taxuskever, een succesvolle plaag uit de Alpen

The vine weevil Otiorchynchus sulcatus is an important pest in the nursery industry and small fruit production but is also a nuisance in gardens and landscapes. In this research is shown that nematodes that parasitize on the weevil larvae find their victims by the chemical substances released by the damaged roots from a conifer. This phenomenon may have huge consequences for the improvement of biological control of this but also many other soil pests in the near futur