Abstract

ZUNIGA, Alfredo; ANGULO, Andrés; REBOLLEDO, Ramón  and  NAVARRO, María E. Comparative differentiation of instars in Helicoverpa zea (Boddie) using cephalic capsule length and distance between frontal setae. Idesia [online]. 2011, vol.29, n.3, pp. 83-86. ISSN 0718-3429.  doi: 10.4067/S0718-34292011000300012.

The corn earworm Heliothis zea has relevant agricultural importance because of the damage it causes in corn and other farms, in direct relation to determined larval instars; effective control will be related to the knowledge of the larval biology. Larvae from northern, central and southern Chile were obtained to establish comparisons for the definition of a specific instar measuring width of cephalic capsule and distance between frontal setae (DFS); these structures present a progressive increase in length proportional to the specific instar. The results indicated significant differences among latitudes and that DFS is a better specific instar predictor than the width of the head capsule. The environmental variables that could be implied in the conditioning of lengths by latitudes are discussed as a projection.

Keywords : Heliothis zea; instars; width of cephalic capsule; distance between frontal setae; Dyar's rule.