INSECT INFESTATION OF FARM-STORED MAIZE IN SOUTH-CAROLINA - TOWARDS CHARACTERIZATION OF A HABITAT

Protecting stored grain from insect damage, with minimum pesticide ris k, will require pest management based on comprehensive understanding o f storage environments and their interactions with pest populations. C omputer modeling offers the means to this understanding. To obtain dat a sets for modeling selected pests of stored maize, we studied maize s torages on six farms in a four-county area of southwestern South Carol ina. Grain moisture content was measured monthly, and grain temperatur es were recorded hourly for one storage season. Insect populations wer e monitored by taking grain and pitfall trap samples at weekly or mont hly intervals. Hourly mean grain temperatures remained below optimal l evels for growth and development of insects during most of the storage period. Grain moisture content varied from 11.2 to 16.4%. Forty three species of insects and one species complex, representing 26 families in four orders, were detected. The estimated importance of each specie s in the farm storage habitat, as measured by relative abundance and f requency of occurrence, depended on whether grain sampling or trapping was used. With trapping, Cryptolestes species (mostly C. pusillus (Sc honherr)), the Carpophilus dimidiatus complex (C. dimidiatus (F.), C. freemani Dobson and C. mutilatus Erichson), Sitophilus species (mostly S. zeamais Motschulsky), Xylocoris flavipes (Reuter) and Oryzaephilus surinamensis (L.) appeared most important. With grain sampling, S. ze amais, Sitotroga cerealella (Olivier) and C. pusillus appeared most im portant. Insects were most abundant (or active) in the fall and again in the spring, if storage extended that long. Grain samples indicated more insects near the grain surface, but traps sometimes detected more near the bottom of the bulk. (C) 1997 Elsevier Science Ltd.