Control of Botrytis cinerea in blackcurrants using biocontrol as part of an integrated programme with conventional fungicides
Abstract: The efficacy of the biocontrol agents (BCAs) Serenade, Prestop, Trianum P andBoniprotect Forte, applied as 4 or 5 spray programmes starting pre-flowering or at first flower forcontrol of Botrytis cinerea fruit rot on blackcurrant cultivars Ben Hope and Ben Tirran wascompared to a standard fungicide programme at similar timings and an untreated control.Programmes based on fungicides for the first 3 sprays followed by one, two or no sprays ofSerenade were also included. The incidence of B. cinerea was assessed on green fruit samples onparaquat agar and on harvested fruit following 7 days damp incubation. The incidence ofB. cinerea fruit rot pre-harvest on bushes was negligible. The incidence of B. cinerea in greenfruit samples varied from 0-100% B. cinerea and in post-harvest tests varied from 0-70%. ForBen Tirran the incidence of Botrytis in post-harvest in untreated fruit was around 12%. Alltreatments, including the BCAs, significantly reduced the incidence of B. cinerea rot compared tothe untreated. Best control was achieved by treatment 2 (4 x fungicide treatments) and 7 (3 earlyfungicides + 2 late Serenade). Replacing the fourth fungicide with two treatments with the BCASerenade appeared to have some benefit in B. cinerea control. B. cinerea rot incidence was morevariable on fruit from Ben Hope most likely due to the drier weather and hence lower botrytisrisk, when this cultivar was flowering. This made the data more difficult to interpret. The lowestincidence of Botrytis in the post-harvest tests was recorded in fruit from treatment 2 (4 xfungicide treatments).