Carabid Density Research Articles

Effects of Bio-dynamic, Organic and Conventional Farming on Ground Beetles (Col. Carabidae) and Other Epigaeic Arthropods in Winter Wheat

ABSTRACT In a long-term comparison of agricultural systems, bio-dynamic, organic and conventional farming have been compared since 1978. The treatments differ mainly in plant protection management and fertilization (organic vs. mineral, and intensity). The experimental field is situated on a Luvisol from loess in Therwil (Switzerland). Here, the fauna of beneficial epigaeic arthropods (carabids, staphylinids and spiders) in differently cultivated winter wheat plots was investigated with pitfall traps (live catches) in 1988, 1990 and 1991. Compared with the conventional plots (= 100%), the bio-dynamic plots contained 193% of epigaeic arthropods, the organic plots 188%. The activity- density of carabids, staphylinids and spiders was higher in the bio-dynamic and the organic than in the conventional plots in all three years. In two out of three years, the difference between the conventional and the biodynamic, organic plots was significant. For carabids, the differences between treatments were most pronounce...

DISTRIBUTION AND DENSITY OF CARABID BEETLES (COLEOPTERA) IN A PEST MANAGEMENT APPLE ORCHARD

AbstractTwo soil sampling techniques were used over a 2 year period to examine the distribution of carabid beetles in a pest management apple orchard in southern Ontario. Soil coring was the most suitable technique for investigating temporal and vertical distribution patterns. Horizontal distribution of individual carabid species was best examined by sampling the rhizosphere of the cover crop only. Comparison of the soil sampling results with those obtained from pitfall traps showed that in late summer carabid larvae are subterranean in habit, as are adults of Bradycellus rupestris Say and Amara spp. Carabid density was highest (289.1 m−2) in late summer and fall, and lowest in late winter. In most samples carabid density was greatest in the rhizosphere of the cover crop and decreased rapidly with increasing depth: few beetles were found at depths greater than 30 cm. In August, densities of the commonest adult carabids were greatest close to trees in the orchard and decreased with increasing distance from trees. The distribution of carabid larvae was not related to distance from the tree, but densities of larvae were higher to the south of trees, and lower to the north.