AN ATTEMPT TO OMIT PESTICIDE SPRAYS BETWEEN FLOWERING AND HARVEST IN THREE BLACK CURRANT CULTIVARS (Ribes nigrum L.) AND EFFECT ON YIELD COMPONENTS, PESTS AND DISEASES.

In general, the number of spray applications was reduced by 2–3 applications when spraying between flowering and harvest was avoided.

Infections caused by leaf spot (Gloeosporidiella ribis) and white pine blister rust (Cronartiun ribicola) were generally higher for 'Ben Alder' and 'Ben Lomond', while the leaf density decreased when no pesticides were used after flowering and before harvest. In 1996 only, ‘Ben Lomond’ had a slightly smaller infection level of mildew (Sphaerotheca mors-uvae) in the normal pesticide schedule.

There was a smaller infestation of spider mites (Tetranychus urticae) in 'Titania', when less pesticide were used.

Growth was reduced for the cultivars 'Ben Alder' and 'Ben Lomond', while 'Titania' maintained the same growth, when sprays on the fruits were omitted. Number of flowers per raceme and fruit set were similar for the two treatments. Yield was reduced in two out of four years in 'Ben Lomond', when no pesticides were used between flowering and harvest, while no differences occurred in 'Titania'.

In 1994, a higher content of dry matter, soluble solids and colour were obtained when spraying was omitted.

With 'Titania' it is possible to omit pesticide sprays on the berries without reduction in yield. However with 'Ben Alder' there is a risk of decreasing yield. It can not be recommended to grow 'Ben Lomond' when spraying between flowering and harvest are avoided.

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