Topography and Crop Management Are Key Factors for the Development of American Leaf Spot Epidemics on Coffee in Costa Rica

Abstract

We monitored the development of American leaf spot of coffee, a disease caused by the gemmiferous fungus Mycena citricolor, in 57 plots in Costa Rica for 1 or 2 years in order to gain a clearer understanding of conditions conducive to the disease and improve its control. During the investigation, characteristics of the coffee trees, crop management, and the environment were recorded. For the analyses, we used partial least-squares regression via the spline functions (PLSS), which is a nonlinear extension to partial least-squares regression (PLS). The fungus developed well in areas located between approximately 1,100 and 1,550 m above sea level. Slopes were conducive to its development, but eastern-facing slopes were less affected than the others, probably because they were more exposed to sunlight, especially in the rainy season. The distance between planting rows, the shade percentage, coffee tree height, the type of shade, and the pruning system explained disease intensity due to their effects on coffee tree shading and, possibly, on the humidity conditions in the plot. Forest trees and fruit trees intercropped with coffee provided particularly propitious conditions. Apparently, fertilization was unfavorable for the disease, probably due to dilution phenomena associated with faster coffee tree growth. Finally, series of wet spells interspersed with dry spells, which were frequent in the middle of the rainy season, were critical for the disease, probably because they affected the production and release of gemmae and their viability. These results could be used to draw up a map of epidemic risks taking topographical factors into account. To reduce those risks and improve chemical control, our results suggested that farmers should space planting rows further apart, maintain light shading in the plantation, and prune their coffee trees.

Plant species diversity for sustainable management of crop pests and diseases in agroecosystems: a review

“…The intensity of attacks by pests and diseases in these systems varies with the pest and its ecological requirements (Schroth et al 2000). In coffee (Coffea arabica), shade has been reported to favour Mycena citricolor in Costa Rica (Avelino et al 2007) (Figs. 15 and 16) but to hamper Colletotrichum kahawae in Cameroon (Mouen Bedimo et al 2008) due to changes in microclimate.…”

Effects of Inga densiflora on the microclimate of coffee (Coffea arabica L.) and overall biomass under optimal growing conditions in Costa Rica

“…It is demonstrated that advantages of associated shade trees are very important for coffee production in poor soils and under sub-optimal ecological conditions (Muschler and Bonnemann 1997; while their effects under optimal conditions remain controversial. On top of reducing coffee flowering intensity and hence yield, shade can result in a very humid micro-environment conducive to higher incidence of fungal diseases such as leaf rust (Hemileia vastatrix) and American leaf spot (Mycena citricolor), especially at high altitude and cloudy conditions (Avelino et al 2006(Avelino et al , 2007.…”

The Intensity of a Bean Fusarium Root Rot Epidemic is Dependent on Planting Strategies

“…The methodological approach chosen was a survey which is a proper method to study epidemics affected by a large number of cropping factors (Avelino et al. ). This method has been used to investigate disease epidemics in soya bean in the north‐central United States (Mila et al.…”