Life Cycles per Annum of Codling Moth and Oriental Fruit Moth

Oriental fruit moth (OFM) larvae pupate in late winter to early spring, with up to five or more generations per season. Infested shoots and terminal leaves wilt and bend over, with this injury known as flagging, and leaves eventually dry up. Flagging stimulates lateral growth below the point of injury, providing wound sites for pathogens (Polk et al., undated). Life cycles per annum were determined by computing degree days (base 10 degree Celsius), utilising 50 years of daily values of maximum and minimum temperatures generated by techniques described in Schulze and Maharaj (2004) at each of - 430 000 one arc minute (1` x 1` latitude by longitude) grid points covering South Africa. The degree days accumulated over one year were then divided by the days required for one life cycle to be completed by codling moths (603 days) and oriental fruit moths (535 days), respectively.