Daños causados por chinche barriga verde Dichelops melacanthus en maíz transgénico Bacillus thuringiensis (Bt)

Transgenic maize expressing Bacillus thuringiensis (Bt) toxin produces a crystal (Cry) protein toxic to caterpillars that is non-toxic to stink bugs. The objectives of this study were to identify the number of plants attacked and not by Dichelops melacanthus, to evaluate foliar damage through the number of punctures, to evaluate plant height and weight of grain production by corn plants attacked and not. The research was carried out on a commercial production agricultural farm in an area 700 m2. Data were recorded, tabulated in Excel spreadsheet and statistically analyzed by T Student test with 5 % of significance for comparison of two independent groups. The results indicate that 80.7 % of corn plants were attacked by D. melacanthus presenting punctures in their leaves. The average height of attacked plants was 41.2 ± 2.2 cm and 41.5 ± 3.3 cm for not attacking. A significant reduction in the production of 23 % was verified. The weight of grains of the attacked plant was on average 3.048 ± 319 g and 3.956 ± 269 g in a not-attacked plant, demonstrating that the damage caused by D. melhacantus reduces Bt corn productivity.El maíz transgénico que expresa la toxina de Bacillus thuringiensis (Bt) produce un cristal (Cry) de proteína tóxica para las orugas de las hojas y los tallos de maíz Bt, pero es atóxica para chinches. Los objetivos de este estudio fueron identificar la cantidad de plantas de maíz atacadas y no por la chinche barriga verde Dichelops melacanthus, evaluar los daños foliares a través del número de punturas, la altura de plantas y la producción en peso de granos de las plantas de maíz atacadas y no. La investigación se realizó en una granja agrícola de producción comercial en una superficie de 700 m2. Los datos fueron registrados en hoja impresa, tabulada en planilla electrónica Excel y analizados estadísticamente por el test T-Student con una significancia del 5 % para comparación de dos grupos de muestras independientes. Los resultados obtenidos indican que el 80,7 % de las plantas de maíz fueron atacadas por la chinche D. melacanthus presentando punturas foliares. La altura promedio de las plantas atacadas fue de 41,2 ± 2,2 cm y 41,5 ± 3,3 cm de las no atacadas. En relación a la producción se ha verificado una reducción significativa del 23 %. El peso de los granos de maíz por planta atacada tuvo un promedio de 3,048 ± 199 g y 3,956 ± 269 g en planta no atacada, demostrando así que los daños ocasionados por D. melacanthus reducen el rendimiento del maíz Bt

Productive and Economic Losses Caused by <em>Dichelops melacanthus</em> in Transgenic Bt Maize <em>Bacillus thuringiensis</em>

Transgenic maize expressing Bacillus thuringiensis (Bt) toxin produces a crystal (Cry) protein toxic to caterpillars that is non-toxic to stink bugs. The objectives of this study were to identify the number of plants attacked and not by Dichelops melacanthus, to evaluate foliar damage through the number of punctures, to evaluate plant height, weight of grain production by corn plants attacked and not and economic loss. The research was carried out on a commercial production agricultural farm in an area of 700 m2. Eight areas were evaluated (10 m × 1.8 m) randomly distributed and in V6 physiological stage. Data were recorded, tabulated in Excel spreadsheet and statistically analysed by T Student test with 5% of significance for comparison of two independent groups. The results indicate that 80.7% of corn plants were attacked by D. melacanthus presenting punctures in their leaves. The average height for attacked plants was 41.2 ± 2.2 cm and 41.5 ± 3.3 cm for not attacked. A significant reduction in production of 23% was verified. The weight of grains of attacked plant was in average 3048 ± 319 g and 3956 ± 269 g in not-attacked plant, demonstrating that the damage caused by D. melhacantus reduces Bt corn productivity and loss of income of 98.93 US dollars per hectare