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.])

2021-07-13T11:11:25+00:00

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.

Savanna woody plants and their provision of food resources to bees in southern Burkina Faso, West Africa

2021-07-13T11:11:24+00:00

West African savanna ecosystems and biodiversity are severely threatened by intensified land use and increasing degradation of natural habitats. Despite the importance of bees for pollinating crops and native plant species little information is available regarding the importance of savanna woody plant species to provide bees with food resources. Flora inventories were carried out on 48 subplots laid out across three land use types. The number of bee morphospecies and their abundance as flower visitors were recorded from inflorescences of plants during the different flowering periods. Out of a total diversity of 82 woody plant species, 53 species (64.63%) from 38 genera and 21 families were melliferous. These plants were visited by bees for foraging nectar and/or pollen. Species of the Combretaceae family were the most visited by bees in terms of individuals (53.85%). Combretum glutinosum alone accounted for 36% of visits. More than half of the melliferous plants (50.94%) were visited for both nectar and pollen. About 32.08% of plants were visited for nectar only (32.08%), while 16.98% were visited for pollen only (16.98%). The majority of savanna plants are flowering in the dry season, but few flowering species can be found throughout the whole year. Savanna woody plant species constitute important food resources for bees, therefore providing a wide range of applications for the development of beekeeping activities in the Sudanian region of West Africa.

Journal of Forest and Landscape Research

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.])

Savanna woody plants and their provision of food resources to bees in southern Burkina Faso, West Africa