Bt Research 2015, Vol.6 No.2 1-10
ISSN 1925-1939
5
From this, it is clear that application of pellet from potato flour
supplemented medium did not favour the healthy life of the
mites with gravid and nymphal stages, which even affected the
adult mites.
Figure 6. Probit analysis. A. Probit graph showing LC
50
value
of
δ
-endotoxin (LB control). Mortality at 48 h of treatment was
taken for the probit analysis. The probit was 2.026 µg/cm
2
. B.
Probit graph showing LC
50
value of
δ
-endotoxin (pellet from
potato flour supplemented medium). Mortality at 48 h of
treatment was taken for the probit analysis. The probit was
1.639 µg/cm
2
.
However, the weight of crude powder in both cases,
and their respective autoclaved controls applied per
cm
2
area on the culture set-up was the same,
i.e
., 1.25
μg, 1.88 μg, 2.5 μg, 3.13 μg and 3.73 μg (all per cm
2
area) concentrations. Hence, the actual toxicity effect
(per mL equivalent) of potato flour supplemented
pellet is 14.44 folds more than that of LB. If the 19%
higher efficacy of flour supplemented pellet, as
described in the preceding paragraph is added to this,
the total efficacy would be over 18 folds more than
LB.
Field trial
The application of crude pellet from potato flour
supplemented medium on the field was also found
highly effective (Fig. 7).The fermented matter was
applied only once on a palm,
i.e.,
prior to monsoon. In
one year, the palms which received the treatment
produced healthy nuts with almost no attack of the
mites. However, for the successful eradication of the
mites, all coconut palms in an area need to be treated
simultaneously.
Figure 7.
Outcome of limited field trial. A. Coconut palm
before treatment with almost no fruits Coconut palm with
uninfested maturing nuts (after 6 months of treatment); and C
coconut palm with almost mature coconuts (after 12 month of
treatment).
Discussions
