priciples of insecticide use in rice ipm

Insecticides in Rice IPM (DRR)
granules 1.0 kg a.i./ha at 30 DAT exhibited very little adverse effect on the P.oryzae at the same time
maintaining good control of the pest. Patnaik and Sathpathy (1983) observed less adverse effect on
P.oryzae by granular insecticides like carbofuran, and phorate but the later was preferable based on
effectiveness on gall midge.
Although sprays are in general not effective against gall midge, they are inevitable against the pests like
leaf folder. Hence, studies were conducted to see their toxicity to gall midge parasite P. oryzae. Among the
sprays, phosalone was the least harmful to the parasitoid, followed by phosphamidon and endosulfan.
EFFECT ON COCCINELLID PREDATORS IN RICE ECOSYSTEM
Among the insecticides viz., chlorpyriphos, fenitrothion, formothion, phosphamidon, and quinalphos, tested
for their toxicity to three coccinellid predators which are commonly found in rice ecosystem viz., Coccinella
rependa, Micraspis discolor and M.vincta, fenitrothion was least toxic to C. repanda, and chlorpyriphos to
M. discolor (Patnaik, 1983). Rabbi et. al. (1993) from Bangladesh observed that cypermethrin, alpha
cypermethrin, diazinon, malathion, fenitrothion and phosphamidon caused low mortalities of the coccinellid
predator, M. discolor among 28 insecticide formulations tested under field conditions. The predatory
carabid beetle, Ophionea indica, which is predatory on BPH, was numerically affected by need-based
application of carbofuran or schedule based application of carbofuran and monocrotophos (Ullah and
Jahan 2004).
EFFECT OF INSECTICIDES ON NATURAL ENEMIES OF LEAF FOLDER
Methamidophos was recommended against leaf folder in China. However, the proper timing of the insecticide
is very essential. Zhuge (1982) suggested that peak of the 3 rd instar of C. medinalis was the most
opportune time for maximum effectiveness against the unparasitized larvae and minimum mortality of
parasitized larvae. However, Zhu et al., (2000) observed that the rate of parasitism by Trichogramma
spp. was significantly affected in plots treated with methamidophos.
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Coccinellid Adult Coccinellid Grub