Ground and rove beetles (Coleoptera: Carabidae and Staphylinidae) are affected by mulches and weeds in highbush blueberries.
Biological control of insects by predators may be indirectly influenced by management practices that change the invertebrate community in agroecosystems. In this study we examined effects that mulching and weeding have on predatory beetles (Carabidae and Staphylinidae) and their potential  prey in a highbush blueberry field. We compared beetle communities in unweeded control plots to those that were weeded and/or received a single application of compost or pine needle mulch. Compost mulch and weeding significantly affected the carabid community while the staphylinid community  responded to compost and pine needle mulches. Effects because of mulch tended to intensify in the year after mulch application for both families. Estimates of species richness and diversity for Carabidae and Staphylinidae were similar in all plot types, but rarefaction curves suggested higher  Carabidae richness in unmulched plots despite fewer individuals captured. Carnivorous Carabidae, dominated by Pterostichus melanarius, were most frequently captured in compost plots both years, and omnivores were most frequently captured in unweeded compost. Density of millipedes, the  most abundant potential prey, was generally greater in mulched plots, whereas seasonal abundance of small earthworms varied among mulch types. Our results have potential implications for biological control in mulched highbush blueberries depending on beetle consumption rates for key pests  and how rates are affected by alternative prey.
Biology Department, Dalhousie University, 1355 Oxford St., Halifax, Nova Scotia, Canada B3H 4J1. jrenkema@nsac.ca
J M
JM
Renkema
D H
DH
Lynch
G C
GC
Cutler
K
K
Mackenzie
S J
SJ
Walde
D000818:Animals; D044822:Biodiversity; D029798:Blueberry Plants; D001517:Coleoptera; D005247:Feeding Behavior; D020387:Food Chain; D011156:Population Density; D012987:Soil
D012987:Soil