Comparative Phytosanitation Studies

Abstract

An understanding of the scope and scale of dispersal of an airborne pathogen such as Crinipellis perniciosa is fundamental to its rational management. This is especially true where phytosanitation is being considered as the main element of a management package, as is often the case with witches’ broom on cocoa. Before embarking on labour-intensive broom removal, a farmer needs to know whether his efforts will be rendered ineffective by inoculum coming from a neighbour’s uncleaned plantation. Similarly, an extension worker or researcher planning a trial of various sanitation practices has to assess if inoculum from uncleaned check plots is likely to interfere with the treated plots, so that adequate guard areas can be included. Otherwise, he runs the risk of underestimating the value of the treatments. To make rational decisions, the farmer, extension worker and researcher would all benefit from information regarding the rate at which disease decreases with increasing distance from a source (the disease gradient), and also on the severity of background infection in a given situation.