GENETICALLY MODIFIED CORN ON Spodoptera frugiperda AND Helicoverpa zea CONTROL IN SINALOA, MEXICO

Luis. A. Aguirre-Uribe*, Agustín Hernández-Juárez, Gustavo A. Frías-Treviño, Mariano Flores-Dávila, Ernesto Cerna-Chávez, Jerónimo Landeros-Flores. Departamento de Parasitología. Universidad Autónoma Agraria Antonio Narro. Calzada Antonio Narro # 1923, Buenavista, Saltillo; Coahuila, México.

*luisaguirreu@yahoo.com.mx

INTRODUCTION

MATERIALS AND METHODS

Two GM corn hybrids were used for this research; Agrisure Viptera 3111 and Agrisure 3000 GT, both effective to control Spodoptera frugiperda and Helicoverpa zea and their respective isolines provided by Syngenta Agro S.A. Research was carried out at El Dorado and Navolato, Sinaloa; Mex., using an experimental design with 8 treatments that included insecticide control(CP) and 4 replicates. Davis scale (Davis et al. 1992); (1=no damage to 9= severe damage) was used to evaluate fall armyworm and length (cm) of damaged corncobs for corn earworm evaluation. A proc ANOVA and a Tukey (P< 0.05) multiple range tests was conducted using the SAS statistic software (SAS, 2002) for variables analyzed.

Different corn hybrids have been genetically modified (GM) with the insertion of genes that express the ∂-endotoxin of Bacillus thuringiensis (Bt) (Bruck et al. 2006), in which the plant expresses the protein with insecticidal activity primarily against Lepidoptera and some Coleoptera insects (Silva, 2005). In Mexico, GM corn planting is not authorized for commercial purposes; however, Bt maize planting was permitted under biosafety conditions to test their pest control effectiveness. The objective of this research was to evaluate Agrisure Viptera 3111 and Agrisure 3000 GT corn hybrids expressing B. thuringiensis toxins on S. frugiperda and H. zea control in Sinaloa, Mexico.

RESULTS

Agrisure Viptera 3111 a

Agrisure Viptera 3111 + CP a

isoline + CP b isoline b0

0.51

1.52

2.53

3.54

1 1

3.53

2.89

Foliar damage by Spodoptera frugiperda

*Treatments with the same letter are not significantly different (P<0.05)

Dav

is s

cale

Fig. 1. Foliar damage and plants with damage by fall armyworm and corncob damage and ears with damage by corn earworm in Agrisure Viptera 3111 and isoline corn at El Dorado, Culiacán; Sinaloa. CP= Crop Protection.

Fig. 2. Foliar damage and plants with damage by fall armyworm and corncob damage and ears with damage by corn earworm in Agrisure 3000 GT and isoline corn at Navolato, Sinaloa. CP= Crop Protection.

Agrisure 3000 GT a

Agrisure 3000 GT + CP a

Isoline + CP b

Isoline b0

1

2

3

4

5

1.34 1.13

3.87

4.97Foliar damage by Spodoptera frugiperda

*Treatments with the same letter are not significantly different (P<0.05)

Dav

is S

cale

Agrisure Viptera 3111 a

Agrisure Viptera 3111 + CP a

isoline + CP b isoline b0

0.5

1

1.5

2

2.5

0.33 0.45

2.2 2.1

Corncob damage by Helicoverpa zea

*Treatments with the same letter are not significantly different (P<0.05)

Gal

lery

(cm

)

Agrisure 3000 GT a

Agrisure 3000 GT + CP a

isoline + CP b isoline b0

1

2

3

4

5

6

0.45 0.27

4.37

5.5

Corncob damage by Helicoverpa zea

*Treatments with the same letter are not significantly different (P<0.05)

Gal

lery

(cm

)

Agrisure Viptera 3111 a

Agrisure Viptera 3111 + CP a

isoline + CP b isoline b0

1020304050607080

0 0

64.456.7

Plants with leaf damage by Spodoptera frugiperda

*Treatments with the same are not significantly different (P<0.05)

Pla

nts

wit

h d

amag

e (%

)

Agrisure Viptera 3111 a

Agrisure Viptera 3111 +

CP a

isoline + CP b isoline b0

20

40

60

80

100

4046.7

93.3 93.3

Ears with damage by Helicoverpa zea

*Treatments with the same letter are not significantly different (P<0.05)

Ear

s w

ith

dam

age

(%)

Agrisure 3000 GT a

Agrisure 3000 GT + CP a

Isoline + CP b

Isoline b0

1020304050607080

13.37.8

66.7

77.8

Plants with leaf damage by Spodoptera frugiperda

*Treatments with the same are not significantly different (P<0.05)

Pla

nts

wit

h d

amag

e (%

)

Agrisure 3000 GT a

Agrisure 3000 GT + CP a

isoline + CP b isoline b0

20

40

60

80

100

56.7

36.7

96.7 100

Ears with damage by Helicoverpa zea

*Treatments with the same letter are not significantly different (P<0.05)

Ear

s w

ith

dam

age

(%)

Agrisure 3000 GT and Agrisure Viptera 3111 hybrids significantly reduced foliar damage (Davis scale) and % plants damaged by fall armyworm S. frugiperda. and corncob lesion size and % cobs damaged by corn earworm, H zea, while the isolines were highly susceptible, with a greater number of plants with injuries and higher foliar and corncob damage at Culiacan and Navolato (Figs. 1 and 2).

This evaluation shows that the GM corn with B. thuringiensis toxin provides permanent protection and not seriously affected by fall armyworm and corn earworm, while insecticidal control to prevent ear damage in field corn is difficult and generally not cost effective and does not significantly reduce fall armyworm damage.

Bt Agrisure Viptera 3111 and Agrisure 3000 GT, probe to be resistant to both pests, increasing the chances to obtain a better grain quality and higher yield.

DISCUSSION

•Bruck, J. D., Lopez, M. D., Lewis L. C., Prasifka J. R. and R. D. Gunnarson. 2006. Effects of Transgenic Bacillus thuringiensis Corn and Permethrin on Nontarget Arthropods. J. Agric. Urban Entomol. 23(3): 111-124.•Davis, F. M.; S. S. NG. and W. P. Williams. 1992. Visual rating scales for screening whorl-stage corn for resistance to fall armyworm. Miss. Agric. Agric. For. Exp. Sta. Technical Bull. 186. 1-9 Pag.•S.A.S. Institute. 2002. The SAS System for Windows, Release 9.0. SAS, Institute, Cary N. C. U.S.A.•Silva, C. C. A. 2005. Maíz Genéticamente Modificado. AGRO-BIO. Bogotá, Colombia. Pág. 60.

LITERATURE CITED