The higher moisture content at the end of the trial may have been partly due to the
high insect numbers. Very few dead weevils were found in the spear samples, but lack
of food in the cone and grain probe traps meant that they contained dead weevils.
While commercial traps for stored grain insects may be expensive, cone traps can be
easily and cheaply constructed (Rees 1999). Grain probes and cone traps are easy to
use, and do not allow insects to escape. They also provide a mechanism for continuous
monitoring of stored-product insects. Detecting low insect populations can give early
warning of potential insect problems (Wright et al. 1988). However, regardless of the
type of trap used, nil insect catches do not mean that there are no insects in the stored
grain since only a small proportion of insects present are captured in the traps. The
distribution of weevils throughout grain stores is not uniform, and different traps have
differing success in trapping weevils in certain locations (A. Carpenter, pers. comm.).