Status and Management of Three Major Insect Pests of Coconut in the Tropics and Subtropics 377
Chandrashekharaiah et al. ( 2012 ) demonstrated
the calling behavior of the female BHC, the male
response toward sex pheromone, and the behav-
ioral responses of male and female O. arenosella
to female pheromone. Studies on exploitation
of pheromone traps as a surveillance and moni-
toring tool in IPM of O. arenosella were also
conducted. Nearly 50 % of population reduction
was found in mass trapping of male BHC moths.
Chandrashekharaiah (2013a) confirmed the dis-
tinct moth emergence periods of BHC males
using pheromone traps and nearly five genera-
tions of BHC/year. The duration of moth emer-
gence and nonemergence periods of moth varied
from 34 to 45 days and 44 to 56 days, respec-
tively. The maximum number of days of moth
emergence and nonemergence was recorded dur-
ing March, April, and May. From these studies,
it is inferred that an average moth emergence pe-
riod lasted for 41.50 days (SD = ± 3.93) followed
by 48.16 (SD = ± 4.35) days of nonemergence
period. The pheromone traps placement should
not be universal or the same for all the places.
But initially, traps should be installed based only
on the visual observation on stage of the pest; in
subsequent generations, the traps can be placed
70–80 days after initial set up.
Chandrashekharaiah et al. (2013b) demon-
strated that the optimum dosage pheromone per
lure was 0.1 mg. Studies on the standardization
of lure type revealed that the commercial plastic
vial type (65.75 moths/trap/generation) was more
effective than vial with cap, black septa, and red
septa (31.50, 56.25, 41.50, and 26.25 moths/trap/
generation). The pheromone release rate profile
of field-installed dispensers quantified at differ-
ent day intervals using gas chromatography with
flame ionization detectors. The results suggested
that, initially, i.e., up to 10 days, the release rate
was maximum (60 and 75 % pheromone released
within 10 and 20 days, respectively) and later, it
was further reduced as the days advanced. The
studies on trap-type standardization indicated
that the commercial cross vane trap (153.40
moths/trap/generation) was more effective than
a wing vane trap (29.66 moths/trap/generation),
wing vane trap with open side (64.60 moths/
trap/generation), wing vane trap with large size
(122.66 moths/trap/generation), and funnel trap
(5.40 moths/trap/generation). The comparison of
the trap with and without pheromone lure indi-
cated that the trap with lure proved more effec-
tive (77.66 moths/trap/generation) than the trap
without lure (23.87 moths/trap/generation).
Chandrashekharaiah et al. (2013c) demon-
strated the robustness of mass trapping technol-
ogy using sex pheromone traps. The study was
conducted in 14.2 ha with 1700 infested coconut
trees. Nearly 661 (I and II generation, respective-
ly) and 836 (III generation) cross vane traps baited
with lure were installed in the study area uniform-
ly. Nearly 73,739, 52,392, and 7953 moths were
trapped in I, II, and III generation, respectively,
with the larval (2.97 ± 0.63 (Mean ± SD) larvae/
leaflet before mass trapping) reduction of 34.27
(1.93 ± 0.64 larvae/leaflet), 88.76 (0.12 ± 0.37 lar-
vae/leaflet) and 93.97 % (0.09 ± 0.03 larvae per
leaf) in II, III, and IV generations, respectively;
whereas in the control plot (2.5 ha), the larval
population was increased continuously up to III
generation (1.83 ± 0.22 to 5.27 ± 2.12 larvae/leaf-
let in I and III generation, respectively) and re-
duced in the subsequent generations. Reduction
in larval numbers was achieved in treated plot
due to continuous trapping of male moths using
pheromone traps.
Chandrashekharaiah (2013a) showed that the
integration of larval parasitoids with pheromone
traps have a cumulative effect on BHC popula-
tion. Further, larval parasitoids can effectively in-
tegrate with pheromone traps without having any
adverse effects. From the above studies, it is con-
firmed that pheromone traps are more effective
in suppressing BHC population than the release
of parasitoids and other methods. Further, they
are eco-friendly, without causing any environ-
mental hazards and safe to nontarget organisms.
The pheromone traps and lures immediately after
mass trapping can be easily collected and buried
in the soil or it can be recycled for further use.
This technology can also be easily combined
with other management practices without any ad-
verse effect. With these results, the pheromone
traps can be recommended for the management
of BHC either alone or in combination with the
release of larval parasitoid, G. nephantidis.