priciples of insecticide use in rice ipm

Tetrastichus sp.
Trichogramma japonicum
Insecticides in Rice IPM (DRR)
Effect of insecticides on egg parasitoides of stem borers
Among various parasitoids, which have been recorded on eggs of
various stem borers in rice ecosystem, Trichogramma japonicum,
Trichogramma chilonis, Telenomus dignoides and Tetrastichus
schoenobi are the most important ones. Hence, an attempt has been
made to present the information available on the toxicity of various
insecticides on these parasitoids separately.
A long-term data of 10 years were utilized for evolving the effect of
chlordimeform, an insecticide routinely used in China for suppressing
the populations of YSB, on the egg parasite T. japonicum (Hong
1990). The results showed that spraying of the insecticide was more
harmful to the parasite than drenching or soil application. The
hatching of the parasite was more adversely affected if spraying
was done 2 days earlier to hatching of host eggs. Ye (1988) from
Nanchang, Jiangxi China observed that of the 8 pesticides commonly Trichogramma sp.
used against YSB, azinphos-methyl, and tetrachlorvinphos caused
lower mortality of the egg parasitoid while piperiphos caused the greatest mortality. Other insecticides
which exhibited moderate adverse effect on T. japonicum were chlormephos-ethyl, primiphos-ethyl,
methamidophos. In general in areas where large quantities of pesticides were used, the egg parasitism
was 1-5 % compared to 24% in areas of lower pesticide usage. Adults of the parasitoid were more
susceptible than the larvae or pupae of the parasitoid.
A detailed laboratory study in DRR (India) based on rate of parasitisation, and emergence of adults of
the parasite revealed that chlorpyriphos and quinalphos at recommended concentration (0.05%) adversely
affected parasitization. (Jhansi lakshmi et al., 1997b). However, comparatively less adverse effect was
observed with regard to neem formulations. A field cum laboratory study by Samanta et. al. (2005) to
evaluate the persistence of synthetic pyrethroid insecticides against YSB egg parasitoids, T. japonicum
and T. chilonis revealed that fluvalinate recorded higher persistency against T. japonicum compared to T.
chilonis, while, reverse trend was observed in case of deltamethrin. Among the others, lindane showed
highest persistency while monocrotophos and quinalphos exhibited moderate persistence.
Telenomus dignoides
Continuous efforts by the scientists of Punjab Agricultural University, Ludhiana, India to evaluate the
adverse effects of insecticides on T. dignoides, revealed that in general, granular formulations of phorate,
carbofuran, quinalphos and cartap (35-40% parasitism) were less toxic than the spray formulations of
chlorpyriphos, monocrotophos and quinalphos and acephate (5-25%) (Singh et al., 1994; Singh and
Sharma 1998). In detailed further investigations, Singh et. al. (2003) observed that granules of cartap
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