EFFECT OF FUNGICIDAL TREATMENTS ON SPORULATING CAPACITY IN RELATION TO CONTROL OF COFFEE BERRY DISEASE

The capacity of the maturing wood of the branches of Coffea arabica to produce conidia of Colletotrichum coffeanum Noack, the causal agent of coffee berry disease, is profoundly affected by fungicidal treatments. The effect differs according to the epidemiology of the disease. When the main source of inoculum is from the wood, the reduction in the sporulating capacity persists throughout the crop‐season, and good control of the disease results. When the main source of inoculum is from diseased berries, reinfection of the branches takes place, the sporulating capacity of sprayed branches rises above that of unsprayed ones, and there is indifferent or no control. Evidence from field trials suggests that the correct timing of early season spray schedules may be related to the part of the annual rhythm of sporulating capacity at which they are applied. As this rhythm is determined by rainfall, and varies from year to year and from place to place, the correct time for the start of a schedule should be predictable from meteorological data. Copyright © 1969, Wiley Blackwell. All rights reserved