N. K. BAJPAI, HEMANT SWAMI AND K. L. JEENGAR1

Survey studies were carried out in farmers’ fields in four maize growing districts of Rajasthan viz., Bhilwara, Chittorgarh, Udaipur and Banswara in 28 talukas, covering 168 villages, 840 fields/farmers and 25,200 plants during 2006 and 2007 to determine the dominant lepidopteran insect pests causing economic losses in maize ecosystem. Stem borer, Chilo partellus (Swinhoe) infestation varied in four districts. Maximum stem borer infestation, 13.17 and 17.19 per cent, was recorded in Bhilwara district during 2006 and 2007, respectively followed by 12.35 and 15.43, 11.28 and 13.83 and 10.16 and 11.25 per cent in Chittorgarh, Banswara and Udaipur districts, respectively with average infestation of 11.74 and 14.43 per cent during 2006 and 2007, respectively. The mean of dead heart, stem borer holes , tunnel length and tassel breakage in surveyed area was 1.59 and 3.55 per cent;16.79 and 23.08 holes per plant;5.93 and 7.08 cm, and0.41 and 1.81 per cent respectively during 2006 and2007. The maize crop is also infested by the pod borer H. armigera and caused cob damage ranging from 0.96 to2.03 and0.39 to2.46 per cent during 2006 and 2007 respectively.