Resistance of sorghum varieties to the shoot fly, Atherigona soccata Rondani (Diptera: Muscidae) in Southern Africa

Abstract

The sorghum shoot fly, Atherigona soccata Rondani (Diptera: Muscidae), is considered to be the predominant shoot fly species attacking sorghum. No information is available on the levels of resistance of to A. soccata sorghum varieties and breeding material released in the countries of the Southern African Development Community. Three field trials were conducted during the 1998/99 to 2001/2002 growing seasons to determine the level of resistance of sorghum varieties to shoot fly. Twenty-five varieties were evaluated in two of the seasons and 24 in the other. High shoot fly densities in the trials were achieved by planting late and using fishmeal to attract flies to the fields. The incidence of dead-heart symptoms in each variety was determined 4 weeks after seedling emergence. Significant differences in resistance to shoot fly damage were observed in two of the three seasons. The incidence of dead-heart symptoms ranged from 32 to 71% during the 1998/99 season, from 27 to 54% during the 1999/2000 season and from 58 to 88% in the 2001/02 seasons. Varieties Pirira-1 and Pirira-2 were the most resistant across seasons. Although the level of resistance in many of the sorghum varieties was low, several varieties with moderate levels of resistance were identified