280
C. R. Krishna Murti and T. S. S. Dikshith
commonly adopted measure. Fumigation with cyanide is made for the control
of infestation of grains. Correlations have been made between the susceptibility
of insects to fumigation with HCN gas and the amount of HCN recoverable from
them immediately after fumigation. Ethylene dibromide is used as a fumigant
for the control of insect and fungal infestation in grain and root crops such as
tapioca. The extent of variation caused by certain factors in the toxicity of
ethylene dichloride-carbon tetrachloride mixture has also been studied (Muthu
and Pingale, 1955). One of the very important factors involved in the fumigation
of infested grains is temperature, but little work has been done in India to
correlate temperature with fumigation practices. Tests have been conducted with
two fumigants, CS2 and ethylene dichloride, using T. castaneum as the test
insect, and the effect of temperatures before, during, and after fumigation on
the toxicity of the compounds has been studied. Temperature and initial moisture
content of grains are two very important factors in the overall effectiveness of
the fumigants, but our knowledge in this area is also very inadequate (Bhatnagar
and Srivastava, 1974).
The use of chemically inert dusts, though reported to be effective by several
workers, has failed in recent studies, and hence does not offer much scope in
the control of pests. Preharvest prophylaxis for infestation control in stored food
grains by using malathion has been suggested. More work, however, seems to
be necessary in this direction before the method can be recommended for general
use. In India, insecticides of plant origin have been safely used on food grains.
The sweet flag powder (Acorus calamus) and pyrethrum have often been suggested for the control of stored-product insect pests. The future of pyrethrum,
however, lies in making less expensive formulations with longer-lasting effects
(Mookhetjee, 1964).
The important means of pest control undoubtedly lies in fumigation. The
use of HCN, CS2, and even naphthalene has been known and recommended for
grain fumigation from early times. Although the most commonly used fumigant
in India is a mixture of ethylene dibromide and carbon tetrachloride (EDCT),
chemicals like ethylene dibromide and a mixture of methyl bromide and ethylene
dibromide or methyl bromide have also been recommended and used. Although
methyl bromide has been used in India for grain fumigation for a long time,
there is a void in our knowledge regarding its use in different commodities,
including the oil seeds. The way it is absorbed in these commodities and ultimately is reacted upon by them to produce harmful residues has not been investigated. The role of the temperature and moisture content of grains on the
overall effectiveness of fumigants commonly used is also still unknown. Phosphine, a well-known fumigant, has been used for the protection of wheat in India
with encouraging results both in stacks and in flat storage as well (Mookhetjee,
1964; Muthu et ai., 1971). However, much remains to be done regarding its
C. R. Krishna Murti and T. S. S. Dikshith
commonly adopted measure. Fumigation with cyanide is made for the control
of infestation of grains. Correlations have been made between the susceptibility
of insects to fumigation with HCN gas and the amount of HCN recoverable from
them immediately after fumigation. Ethylene dibromide is used as a fumigant
for the control of insect and fungal infestation in grain and root crops such as
tapioca. The extent of variation caused by certain factors in the toxicity of
ethylene dichloride-carbon tetrachloride mixture has also been studied (Muthu
and Pingale, 1955). One of the very important factors involved in the fumigation
of infested grains is temperature, but little work has been done in India to
correlate temperature with fumigation practices. Tests have been conducted with
two fumigants, CS2 and ethylene dichloride, using T. castaneum as the test
insect, and the effect of temperatures before, during, and after fumigation on
the toxicity of the compounds has been studied. Temperature and initial moisture
content of grains are two very important factors in the overall effectiveness of
the fumigants, but our knowledge in this area is also very inadequate (Bhatnagar
and Srivastava, 1974).
The use of chemically inert dusts, though reported to be effective by several
workers, has failed in recent studies, and hence does not offer much scope in
the control of pests. Preharvest prophylaxis for infestation control in stored food
grains by using malathion has been suggested. More work, however, seems to
be necessary in this direction before the method can be recommended for general
use. In India, insecticides of plant origin have been safely used on food grains.
The sweet flag powder (Acorus calamus) and pyrethrum have often been suggested for the control of stored-product insect pests. The future of pyrethrum,
however, lies in making less expensive formulations with longer-lasting effects
(Mookhetjee, 1964).
The important means of pest control undoubtedly lies in fumigation. The
use of HCN, CS2, and even naphthalene has been known and recommended for
grain fumigation from early times. Although the most commonly used fumigant
in India is a mixture of ethylene dibromide and carbon tetrachloride (EDCT),
chemicals like ethylene dibromide and a mixture of methyl bromide and ethylene
dibromide or methyl bromide have also been recommended and used. Although
methyl bromide has been used in India for grain fumigation for a long time,
there is a void in our knowledge regarding its use in different commodities,
including the oil seeds. The way it is absorbed in these commodities and ultimately is reacted upon by them to produce harmful residues has not been investigated. The role of the temperature and moisture content of grains on the
overall effectiveness of fumigants commonly used is also still unknown. Phosphine, a well-known fumigant, has been used for the protection of wheat in India
with encouraging results both in stacks and in flat storage as well (Mookhetjee,
1964; Muthu et ai., 1971). However, much remains to be done regarding its