Contents - Faperta

108 Biotechnological Approaches for Pest Management and Ecological Sustainability
Pod damage (%)
80
70
60
50
40
30
20
10
0
ICPL 87 ICPL 332
Endosulfan Untreated control
FIGURE 4.11 Effect of insecticide application (one spray of 0.07% endosulfan) on pod damage by Helicoverpa
armigera, and grain yield in a susceptible (ICPL 87) and resistant (ICPL 332) cultivars of pigeonpea.
Reduced insecticide use on vegetables and fruits for controlling insects not only benefi ts
the agroecosystem and the natural enemies, but also results in lower insecticide residues
in the food. The susceptibility of white backed planthopper, Sogatella furcifera (Horvath)
and brown planthopper N. lugens to insecticides is affected by the level of plant resistance
in the rice cultivars. Planthoppers reared on moderately resistant rice varieties had lower
LD 50 values than those reared on the susceptible varieties (Heinrichs et al., 1984). A combination
of moderate levels of plant resistance and insecticide application can be used for
effective control of insect pests. Application of carbofuran granules results in a signifi cant
reduction in deadheart formation due to shoot fl y in sorghum cultivars with moderate
levels of resistance (M 35-1 and ICSV 705), but there is no effect of carbofuran application
on shoot fl y damage on the susceptible cultivar, CSH 1 (Figure 4.12). Maximum grain yield
in sorghum has been realized with four sprays of demeton-S-methyl against sorghum
head bug, C. angustatus on IS 9692 and CSH 11, whereas only one to two sprays are
suffi cient to realize the maximum yield potential of the head bug-resistant genotypes,
Deadhearts (%)
100
90
80
70
60
50
40
30
20
10
0
CSH 1 M 35-1 ICSV 705
Treated (%DH) Nontreated (%DH)
FIGURE 4.12 Effect of carbofuran treatment on deadheart formation due to sorghum shoot fl y, Atherigona
soccata in susceptible (CSH 1) and moderately resistant (M 35-1 and ICSV 705) cultivars of sorghum.