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Stored sorghum grain should be examined regularly to
detect early infestations of insects so they can be controlled before extensive damage
occurs. During cool times of the year, grain should be checked every four to six weeks,
but during warm seasons, grain should be checked every two to four weeks. A systematic
sampling procedure using a grain probe should be used. The probe should be inserted
horizontally 5 cm under the grain surface in the center of the bin where the grain surface
has not been disturbed. Additional samples should be collected from the sides of the bin.
Samples should be taken no farther than 6 m apart. After sampling the grain near the
surface, the probe should be inserted into the grain mass from top to bottom. Each sample
of grain should be placed in a tray long enough to accommodate the grain probe and
examined for insects. Sieves designed for sorghum grain aid in examining for insects. Pheromone-baited sticky traps can be used to monitor for stored grain moths.
A grain probe trap will detect most insects infesting stored sorghum grain. This trap is a
plastic probe about 37.5 cm long that functions as a pitfall trap for grain beetles and
their larvae. Two to four grain probe traps placed into the surface of grain during a
forty-eight-hour period will trap insects. Collection of ten or more insects per probe
during a twenty-four-hour period is cause for concern. Using the regular grain probe, one
primary pest beetle per quart of grain is a damaging infestation. Five secondary insect
pests per quart of grain are damaging. |
