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Benefit/cost ratio was calculated by comparison of
the cost of protective sprays and net gain over the control
treatments.
The data (Table 1) show that field application of 3
sprays of endosulfan against H. armigera in chickpea
resulted in significant reduction in pod damage at maturity
and increased grain yield in both years. The application
of endosulfan, 0.07%, gave maximum protection with
minimum pod damage 40.2% and 29.3% and highest
grain yield 2.12 and 2.27 t ha -1 respectively. Pod damage
at maturity varied from 44% to 65% with grain yield 0.29
to 1.29 t ha 1 in treated plots in 1992-1993 as compared
to 81.7% and 0.2 t ha -1 in untreated control plots. Similar
trend was observed in 1993-94 with varied pod damage
51-70% and grain yield 1.34-1.65 t ha -1 as compared to
70% damage and 0.83 t ha -1 yield in untreated control
plots. The treatment of crop with karanj oil during
1992-93 resulted in minimum pod damage, 44% with
maximum grain yield, percent increase in grain yield
over control and percent avoidable yield loss, i.e., 1.29 t
ha -1 , 54.5% and 84.5% respectively among various
bioproducts tested. In 1993-94, the plots treated with nicotine
sulphate gave lowest pod damage, 51% but treatment
with neem oil gave maximum grain yield, percent
increase in grain yield over control and avoidable yield
loss, i.e., 1.65 t ha -1 , 99% and 50% respectively followed
by karanj oil and green mark.
The data on the economics of different treatments
show that endosulfan gave the maximum benefit/cost
ratio, 14.8 in 1992-93 and 14.1 in 1993-94. Among the
botanicals tested, green mark gave highest ratio, 6.3
followed by karanj oil, 5.1 in 1992-93 and NSKWE, 9.2
followed by green mark, 5.8 in 1993-94.
Neem, karanj, and tobacco formulations, when tested
under heavy pest pressure at Pantnagar as in these studies
and even in the All India Pulse Project data cited by Lal
et al. (1986) were less effective than endosulfan. Similarly,
Rao et al. (1990) had reported that neem oil was not
effective against H. armigera and resulted in less yield
of cotton seed. Gupta et al. 1990 had reported that application
of karanj oil 3% and 5% reduced the pod damage
of H. armigera to