Contents - Faperta

Deployment of Insect-Resistant Transgenic Crops for Pest Management 321
Boll damage (%)
120
100
80
60
40
20
0
Bt NBt Bt NBt Bt NBt Bt NBt Bt NBt Bt NBt
UP CP UP CP UP CP
Mech 12 Mech 162 Mech 184
FIGURE 10.3 Cotton bollworm/legume pod borer, Helicoverpa armigera, damage in three cotton cry1Ac transgenic
hybrids under protected and unprotected conditions. UP, unprotected; CP, completely protected.
Mech 162 (6 to 14 jassids per plant) (Figure 10.5). Under farmers’ fi eld conditions, the
transgenic hybrid Mech 162 suffered less damage by the bollworms, H. armigera and
P. gossypiella (11.5%) as compared to the conventional cotton (29.4%) in plots under
integrated pest management (Bambawale et al., 2004). Only three sprays were needed for
pest control on the transgenic cotton compared to seven sprays on the conventional cotton
variety. Qaim and Zilberman (2003) reported that pesticide use was reduced by 70% on the
Bt-transgenic hybrids, while the yields increased by 60%.
Cereals
Maize plants with cryIAb (Koziel et al., 1993; Armstrong et al., 1995; Archer et al., 2000) and
cry9C ( Jansens et al., 1997) are highly effective against the European corn borer (ECB),
Ostrinia nubilalis (Hubner). Transgenic maize with Bt genes has also been found to be effective
against the spotted stem borer, Chilo partellus (Swinhoe) and maize stalk borer, Busseola
Yield (kg/ha)
3500
3000
2500
2000
1500
1000
500
0
Completely protected
I I II II I I II II I I II II
Bt NBt Bt NBt Bt NBt Bt NBt Bt NBt Bt NBt
Mech 184 Mech 162 Mech 12
FIGURE 10.4 Cottonseed yield in three cotton cry1Ac transgenic hybrids under protected and unprotected
conditions. I and II, First and second picking, respectively.