SEASONAL FEEDING BY PHYLLOPHAGA-CRINITA AND ANOMALA SPP (COLEOPTERA, SCARABAEIDAE) LARVAE IN NORTHEASTERN MEXICO

Larval feeding by Phyllophaga crinita (Burmeister) and Anomala spp. (m ixed populations of A. flavipernnis Burmeister and A. foraminosa Bates ) was studied under simulated field conditions in northern Tamaulipas, Mexico. Each month from July 1994 to February 1995, 50 field-collecte d larvae of P. crinita and Anomala spp. were placed individually in pl astic pots with soil and corn seeds, and damage was evaluated 10 d aft er seedling emergence. Second-instar P. crinita caused 41% root loss i n July, whereas third instars caused most damage (66-88% root loss) du ring July-September. Feeding by P. crinita decreased gradually from Oc tober to December, and ceased in January-February. In contrast, feedin g by Anomala spp. peaked in July and again in November (73 and 53% roo t loss, respectively), a result of the bivoltine life cycle of these s pecies in this region. The relationship of these findings to similar s tudies is discussed.