Preliminary Observations on the Impact of Whitegrub on Sugarcane Yields in the Midlands North Region of the South African Sugar Industry

During 1995 to 2001, two research trials and two farms in the Midlands region of the industry were monitored for yield effects attributable to whitegrub (various species of Scarabaeoidea). Although the trials were designed for other purposes, severe whitegrub infestations were observed in the soils on which the trials were situated, and the opportunity was taken to assess the impact of this soil pest on crop yield. Results showed that there was an average reduction in yield (tons cane/ha) of between 55 and 23%, depending on variety and season. Such losses cannot be entirely explained by factors such as normal yield decline, and it is concluded that these losses may be ascribed to the activity of whitegrub.