RA 00015.pdf - OAR@ICRISAT

Products Institute, London. The major pheromone
caught significantly more moths than all
other treatments, and there was an indication
that the minor pheromone was an inhibitor -
since fewer moths were caught than with the
virgin female and even fewer than in the "control"
water traps (Fig 10). We recorded significant
differences in catch over nights but this was
not solely due to ageing of the pheromone, since
peaks were recorded in the water traps also. The
peaks appeared to be associated with irrigation
of the experimental blocks or adjacent areas or
with rain (Fig 11). In subsequent experiments in
which we compared the ratios of major to minor
pheromone with virgin females, six parts of
major to one part minor was optimal for catch,
50
45
40
35
30
but all pheromone traps caught fewer male
moths than did the virgin females. The synthetic
pheromones were active for up to 49 days.
Screening for Pest Resistance
Shoot fly. We screened a large amount of the
sorghum germplasm for shoot-fly resistance,
using the fish meal and interlard technique. Two
groups of elite material which had previously
performed well were submitted to high levels of
attack using a grid system. IS 1054, 2146, 2162,
2312, 5604, 5604 x 23/2, 5613, 5622, and 5648
were confirmed as nonpreferred for oviposition.
Lines recently collected from farmers' fields by
germplasm botanists and untested IS lines were
grown twice, and IS 1119, 5296, 5113, 2195,
5480, and 8311 were nonpreferred for oviposition.
Taking subsequent dead heart and
head production counts into consideration, IS
1119, 5480, 2176, and 2195 were selected for
further investigation.
Lines showing some shoot-fly tolerance were
grown in larger blocks at three scattered sites at
ICRISAT Center. IS 1082, 2312, 4002, 4036,
4829, 5642 and derivatives IS 1082 x WABC
4062, IS 5642 x R 960, EN 3308, and EN 3362-1
25
55
50
Rain
20
40
15
30
10
20
5
10
Major Major Minor Virgin Water
Phero- plus Phero- Female
mone minor mone
0
1 2 3 4 5 6 7 8 9 10 1112 13 14 15
N i g h t s
Figure 10. Mean daily catch of Chilo partellus
males on five treatments over 15 nights
at ICRISAT Center (March 1977).
Figure 11. Mean nightly catch of Chilo partellus
over 15 nights in 15 traps at ICRISAT
Center (March 1977).
40