Assessment of Yield Loss in Maize due to Attack by the Maize Borer, <i>Chilo partellus</i> (Swinhoe)

Abstract

The maize borer, Chilo partellus (Swinhoe), is one of the major biotic constrains reducing maize productivity in Nepal. Summer maize is infested mainly by it rather than by other insect species in Nepal. National Maize Research Program (NMRP)-Rampur farm was considered as a potential spot for this study where summer maize is highly infested every year by this pest. This study was conducted during the summers of 2004 and 2005 with an objective of assessing the loss by it in maize. A maize variety, Arun-2, was used in this study. Yield loss by this pest was estimated by obtaining the yield difference between the chemically protected and unprotected maize plants. Number of plant stands, number of stem breakage, number of ears harvested, number of poor cobs, 1000 grain weight, and stem tunneling were also recorded as the yield affecting factors. The yield difference was significantly less (by 28%) in unprotected maize as compared to protected maize. Number of plant stands, number of ears harvested and 1000 grain weight were found less (by 8.5, 14, and 6%, respectively) whereas number of stem breakage, number of poor cobs, length of tunnels per plant and per tunnel length were found higher (by 16, 6, 30, and 24%, respectively) in unprotected maize. This study has suggested that application of plant protection measures against C. patellus can significantly increase maize productivity and hence can greatly contribute in poverty alleviation in Nepal.

Key words: maize borer; Chilo partellus; yield loss assessment; maize

DOI: 10.3126/njst.v11i0.4085

Nepal Journal of Science and Technology 11 (2010) 25-30

The maize borer, Chilo partellus (Swinhoe), is one of the major biotic constrains reducing maize productivity in Nepal. Summer maize is infested mainly by it rather than by other insect species in Nepal. National Maize Research Program (NMRP)-Rampur farm was considered as a potential spot for this study where summer maize is highly infested every year by this pest. This study was conducted during the summers of 2004 and 2005 with an objective of assessing the loss by it in maize. A maize variety, Arun-2, was used in this study. Yield loss by this pest was estimated by obtaining the yield difference between the chemically protected and unprotected maize plants. Number of plant stands, number of stem breakage, number of ears harvested, number of poor cobs, 1000 grain weight, and stem tunneling were also recorded as the yield affecting factors. The yield difference was significantly less (by 28%) in unprotected maize as compared to protected maize. Number of plant stands, number of ears harvested and 1000 grain weight were found less (by 8.5, 14, and 6%, respectively) whereas number of stem breakage, number of poor cobs, length of tunnels per plant and per tunnel length were found higher (by 16, 6, 30, and 24%, respectively) in unprotected maize. This study has suggested that application of plant protection measures against C. patellus can significantly increase maize productivity and hence can greatly contribute in poverty alleviation in Nepal. Key words: maize borer, Chilo partellus, yield loss assessment, maize