Evaluation of the response of three maize hybrids against European Corn Borer, Ostrinia nubilalis in different sowing dates in the Moghan region

This research was carried out to evaluate the effect of sowing date on the severity of infestation and damage of European Corn Borrer (ECB) on three maize hybrids. Two separate experiments (with and without insecticide spraying against ECB) were conducted as a factorial experiment with two factors including sowing date at three levels (25th April, 10th May and 25th May) and hybrids at three levels (SC704, SC705- and SC706) based on randomized complete block design with four replications for two years in Moghan region, Iran. The results showed that the grain yield of the studied hybrids under spraying conditions with 13.28 t ha-1 was significantly higher than the no spraying conditions with 11.45 t ha-1. This shows that no spraying against this pest reduced grain yield by 1830 kg ha-1 (13.80%). The results also showed that in both spraying and no spraying conditions, 25th May sowing date had the highest grain yield with 14.57 and 12.98 t ha-1, respectively. In no spraying conditions, SC706 hybrid with 12.19 t ha-1 showed significantly higher grain yield than SC704 and SC705 hybrids with 11.38 and 10.78 t ha-1 grain yield, respectively. Based on the two-year average, the SC706 hybrid also had the lowest number of holes per stem, tunnel length per plant, percentage of plant infestation and percentage of stalk breakage due to the pest damage. Therefore, the SC706 hybrid is a productive hybrid that is relatively tolerant against ECB.