Despite the availability of modern technologies for grain
storage and pest control, some farmers still use traditional
methods of storage, such as corn in the cob in small cribs
and rice stored in boxes or bags. Grain stored under such
conditions is very susceptible to heavy losses (Amorim
1986). In warmer regions, natural aeration is not sufficient
to control infestations, requiring the application of chemical
control (Moreira 1993). The most effective and fast
method to suppress stored grain pests is fumigation. Nowadays,
phosphine is the most used fumigant, even though its
use has several disadvantages. It corrodes non-ferric metals,
requires a long aeration period, is inflammable in high
concentrations and is acutely toxic and may cause depreciation
of the value of the fumigated product (Santos 2006).
The incorrect use of phosphine has selected resistant pest
populations (Rosseto 1966; Calil 1995). The use of a mixture of insecticides also favors the development of resistant strains which then makes subsequent pest management difficult
(Pereira et al. 1997).