Control of bacterial black spot with modified copper sprays.
Manicom B. Q., Smith H.
Author Affiliation: Institute for Tropical and Subtropical Crops, Private Bag X11208, Nelspruit 1200, South Africa.
: 58-60
Abstract : A trial was conducted at Bavaria Estates, South Africa to test the effect of modifying fixed copper sprays (hereinafter referred to as copper sprays) to release more Cu2+ on the incidence of bacterial spot [Xanthomonas campestris pv. mangiferaeindicae] and to determine whether using less copper would be as effective. The treatments consisted of two application methods, i.e. high (2500 l/ha) vs. low volume (1000 l/ha); five chemical treatments, i.e. Demildex [copper oxychloride] at 300 g/hl, Copper Plus at 300 g/hl applied singly or in combination with Breakthru (siloxane wetter) or Bion [acibenzolar-S-methyl] at 12 g/hl, and Copper Plus at 300 g/hl for the first spray followed by Copper Plus at 100 g/hl; and two fruit capping treatments (capped vs. uncapped). Copper spray applications commenced on 1 September 1998 and continued at 15-day intervals until 5 January 1999 for a total of 9 applications. Bion was applied with the spray nearest the beginning of each month for 5 applications. Fruits were rated on 21 January 1999. Spraying method had no significant difference on infection, but high volume sprays were more effective than low volume sprays where fruits were capped. Copper Plus significantly controlled bacterial black spot of mango. However, addition of Breakthru or Bion decreased the efficacy of Copper Plus.