Loss of sunflower seeds to columbids in South Africa: economic implications and control measures
AbstractA survey across the sunflower production region of South Africa during November 2003 to July 2005 estimated the loss of sunflower seeds to columbids (doves and pigeons, Aves: Columbidae). Farmers estimated that 12.7% of the national yield was lost to columbids. In a follow-up survey, 37 sunflower fields were visited and accurate measurements applied to assess seed loss, suggesting a national loss of 8.4% (loss in revenue of R197 million). In rows with east–west orientation the mean seed loss was 8.2% and in the north–south orientation the mean seed loss was 5%. There was a non-significant positive correlation (r = 0.270, p > 0.05) between the distance between plants in a row and percentage seed loss. No correlation was found between field size and percentage seed loss (r = –0.35, p > 0.05). Most damage occurred in the centre of the sunflower fields with a mean loss of 10.09% (range 0.08–32.24, SD = 8.88, n = 22) as against 4.76% (range 0.5–11.82, SD = 3.46, n = 22) on the edge. Seed losses did not vary significantly among provinces (analysis of variance, F2,34 = 2.11, p = 0.136). Proposed control measures are discussed.
Ostrich 2009, 80(1): 47–52