Author
 |
Byers, Robert |
|
BARKER, G - LANDCARE RESEARCH LTD. |
|
Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 5/20/2000 Publication Date: 6/20/2000 Citation: Byers, R.A., Barker, G.M. , Davidson, R. L., Hoebeke, E. R., Sanderson, M. A.2000. Richness and abundance of Carabidae and Staphylinidae (Coleopter), in northeastern dairy pastures under intensive grazing. Great Lakes Entomologist. 33(2) p.81-105. Interpretive Summary: Intensive grazing management of cattle to cut feed costs and produce milk with fewer inputs in stored feed has led to the concern whether intensive grazing will cause pest problems. A survey of insects in pastures in three northeastern states over 4 years concluded that most of the injurious insects that attack and injure turf grasses infest pastures, but populations are lower than those found in turf and cropped forages. The clover root curculio, a pest of alfalfa and clover roots, was widely distributed and associated with pastures containing white clover. This insect has the potential to limit clover production, both by its feeding and making roots susceptible to root pathogens. Current grazing management practices have not led to pest problems, but the potential for pests to increase may change in the future if grazing management intensifies or plant diversity varies from the vegetative diverse pasture mixtures to less scomplex systems. Technical Abstract: Rotational intensive grazing of pastures during spring and summer has become an important way to cut feed costs and increase efficiency in milk production in the northeastern (NE) United States. It is not known whether the major insect pests of pasture grasses and legumes which includes species of Coleopteran families of Scarabaeidae (white grubs) and Curculionidae (billbugs and other weevils) are important in these pastures An insect survey of intensively grazed pastures was conducted in Pennsylvania, New York, and Vermont. Pitfall catches of 35 species of Curculionidae in all three states were dominated by five species: a clover seed weevil, Tychius picrirostris (F.); the clover root curculio, Sitona hispidulus (F.); clover leaf weevil, Hypera punctata (F.); and two billbugs, Sphenophorus parvalus Gyll. and Sphenophorus minimus Hart. Pitfall catches of 20 species of Scarabaeidae were dominated by four known grass feeding pests, Aphodius granarius (L.); A. stercorosus Melsheimer, A erraticus (L.); Ataenius spretulus (Haldeman), Ataenius strigatus (Say); and a dung beetle, Onthophagus nuchicornis (L.). The botanical composition of most pastures was dominated by either Poa pratensis L. (24-57%) or Dactylis glomerata L. (5-22%) with 15 other grasses averaging less than 10%. Trifolium repens L. was the dominant legume (8-17%), with 5 other legumes averaging less than 2%. Weeds averaged 9-14% of the composition. Our results show species of weevils and scarabs that injure turfgrass and legumes also occur in pastures, but at lower population densities. Current grazing management practices have not caused pest problems, but this may change in the future if grazing management intensifies or plant diversity varies from the vegetative diverse pasture mixtures to simpler systems. |
