282
C. R. Krishna Murti and T. S. S. Dikshith
chemical constituents in addition to their utility in insect control have been
investigated. Application of dicrotophos, monocrotophos, endosulfan, and chlorfenvinphos altered the biochemical constituents of brinjal plants (Uttamaswamy
et al., 1976). It was reported that changes brought about by these in phenolics,
sugars, and minerals appeared to influence the population of the red spider mite.
Investigations on the effect of parathion on the pea crop have revealed that
residues could lead to a marginal increase in the protein content, whereas sulfur
and phosphorus contents remained unaffected (Jagirdar et al., 1974). The contents of reducing and total sugars decreased significantly at the time of harvest,
while nonreducing sugars were maximum at this period. Carbaryl and cytrolane
also brought about changes in phenolics and sugars in brinjal plants (Kumaresan
and Bhaskaran, 1975). In contrast to cytrolane, the carbaryl-treated plant showed
a lesser increase in phenolics, and correspondingly the insect infestation was
more than that in cytrolane-treated and control plants. Contents of reducing and
nonreducing sugars were found likely to be enhanced in the treated plants.
Effects of the treatment of insecticides on the crop yield have also been
investigated (Chakraborty et al., 1973; Chatterjee, 1972). A significant difference
in the grain yield was obtained in insecticide-treated (phosphamidon, fenitrothion, and lindane) plots over controls. A high dose of lindane mixed with urea
registered the highest yield, closely followed by phosphamidon when applied
singly. The maximum yield was obtained in the plots that received fenitrothion,
followed by lindane and phosphamidon, respectively (Chakraborty et al., 1973).
Malathion, sumithion, sevin, and thiodan lead to an increase in yield over control
on paddies (Chatterjee, 1972).
A single administration of endrin (3 J.Lg) to the adult male grasshopper
Poecilocerus pictus reduced the activity of alkaline and acid phosphatases in
hemolymph and testicular tissue, but not in alimentary tissues of the insects
(Vasuki and Dikshith, 1968). The pattern of the two enzymes after endrin treatment in vitro using a coccid, Dactylopous confusus, as the test system suggested
a gradual inhibition of alkaline phosphatase activity and indicated a dose dependency (Dikshith and Vasuki, 1970).
Isolation of active compounds from a variety of plants and their identification
for insecticidal activity has been pursued with some positive results. Several
species of plants grown in India were examined for the insecticidal property.
The insecticidal activity of the active material isolated through solvent extraction
and steam evaporation of plants suggested that they do possess insecticidal
properties and could control insect pests without causing deleterious effects to
higher animals and man. Extracts of A. calamus L. (sweet flag) were found to
be toxic to flies and mosquitoes, and a significant knockdown effect was noticed
in them in comparison to DDT. The active compound showed a synergistic effect
with DDT. Woolen fabrics treated with the extract were not affected by the
woolly bear. Seed oil of Anona squamosa L. (custard apple) was found to be
C. R. Krishna Murti and T. S. S. Dikshith
chemical constituents in addition to their utility in insect control have been
investigated. Application of dicrotophos, monocrotophos, endosulfan, and chlorfenvinphos altered the biochemical constituents of brinjal plants (Uttamaswamy
et al., 1976). It was reported that changes brought about by these in phenolics,
sugars, and minerals appeared to influence the population of the red spider mite.
Investigations on the effect of parathion on the pea crop have revealed that
residues could lead to a marginal increase in the protein content, whereas sulfur
and phosphorus contents remained unaffected (Jagirdar et al., 1974). The contents of reducing and total sugars decreased significantly at the time of harvest,
while nonreducing sugars were maximum at this period. Carbaryl and cytrolane
also brought about changes in phenolics and sugars in brinjal plants (Kumaresan
and Bhaskaran, 1975). In contrast to cytrolane, the carbaryl-treated plant showed
a lesser increase in phenolics, and correspondingly the insect infestation was
more than that in cytrolane-treated and control plants. Contents of reducing and
nonreducing sugars were found likely to be enhanced in the treated plants.
Effects of the treatment of insecticides on the crop yield have also been
investigated (Chakraborty et al., 1973; Chatterjee, 1972). A significant difference
in the grain yield was obtained in insecticide-treated (phosphamidon, fenitrothion, and lindane) plots over controls. A high dose of lindane mixed with urea
registered the highest yield, closely followed by phosphamidon when applied
singly. The maximum yield was obtained in the plots that received fenitrothion,
followed by lindane and phosphamidon, respectively (Chakraborty et al., 1973).
Malathion, sumithion, sevin, and thiodan lead to an increase in yield over control
on paddies (Chatterjee, 1972).
A single administration of endrin (3 J.Lg) to the adult male grasshopper
Poecilocerus pictus reduced the activity of alkaline and acid phosphatases in
hemolymph and testicular tissue, but not in alimentary tissues of the insects
(Vasuki and Dikshith, 1968). The pattern of the two enzymes after endrin treatment in vitro using a coccid, Dactylopous confusus, as the test system suggested
a gradual inhibition of alkaline phosphatase activity and indicated a dose dependency (Dikshith and Vasuki, 1970).
Isolation of active compounds from a variety of plants and their identification
for insecticidal activity has been pursued with some positive results. Several
species of plants grown in India were examined for the insecticidal property.
The insecticidal activity of the active material isolated through solvent extraction
and steam evaporation of plants suggested that they do possess insecticidal
properties and could control insect pests without causing deleterious effects to
higher animals and man. Extracts of A. calamus L. (sweet flag) were found to
be toxic to flies and mosquitoes, and a significant knockdown effect was noticed
in them in comparison to DDT. The active compound showed a synergistic effect
with DDT. Woolen fabrics treated with the extract were not affected by the
woolly bear. Seed oil of Anona squamosa L. (custard apple) was found to be