percentage weight losses of milled rice in
BULOG's warehouses may reach 0.35% after 6
months storage. This value is much lower than
weight losses from milled rice infested with insects
in laboratory conditions. Sidik (1979), using 54 kg
drums filled with rice and infested with Sitophi!us
zeamais. recorded weight losses as high as 22%
after 6 months. Husain (1982) recorded a weight
loss from milled rice due to S. zeamais infestation
of 14.8% in 3 months.
There are several factors affecting the extent of
weight losses from milled rice caused by insects
during storage. These include the variety of the rice
involved, storage conditions, and pest control
practices. Husain (1982) noted that the order of
susceptibility to insect attack of varieties of rice
stored in Indonesia was: Cisadane, IR. 36,
Cimandiri, and IR. 32. Both Cisadane and IR. 36
are high-yielding varieties of rice which are widely
grown in this country and apparently suffer more
severe damage than any other varieties. Therefore,
it can be predicted that insects contribute great loss
and damage to stored, milled rice in Indonesia.
Among the various storage insects, those most
commonly encountered and considered as being
most important in terms of losses and damage to ,
stored grains in Indonesia are as follows.
Sitophilus spp. are recognised as the major,
primary pests of whole cereal grains. It is now
becoming more widely known that Sitophilus
zeamais is the dominant species on most cereals,
especially maize and rice, in the tropics. As a
result, it has been assumed that in Indonesia the
Sitophilus found on maize and all forms of rice are
S. zeamais. S. zeamais does indeed appear to be
dominant over S. oryzae on milled rice and maize
in Java, but not completely so (McFarlane 1978;
Haines and Pranata 1982). S. oryzae has also been
found infesting green gram and black soya, and the
observed frequency of occurrence of S. oryzae on
pulses indicates that a pulse-feeding strain is quite
common in Java.