Hemileia vastatrix caused a severe epidemic in Central America in 2012−13. The gradual development of that epidemic on nearly a continental scale suggests that dispersal at different scales played a significant role. Shade has been proposed as a way of reducing uredospore dispersal. The effect of shade (two strata: Erythrina poeppigiana below and Chloroleucon eurycyclum above) and full sun on H. vastatrix dispersal was studied with Burkard traps in relation to meteorological records. Annual and daily patterns of dispersal were observed, with peaks of uredospore capture obtained during wet seasons and in the early afternoon. A maximum of 464 uredospores in 1 day (in 14.4 m³ of air) was recorded in October 2014. Interactions between shade/full sun and meteorological conditions were found. Rainfall, possibly intercepted by tree cover and redistributed by raindrops of higher kinetic energy, was the main driver of uredospore dispersal under shade. Wind gusts reversed this effect, probably by inhibiting water accumulation on leaves. Wind gusts also promoted dispersal under dry conditions in full sun, whereas they had no effect under shaded conditions, probably because the canopy blocked the wind. Our results indicate the importance of managing shade cover differentially in rainy versus dry periods to control the dispersal of airborne H. vastatrix uredospores.

Shaded perennial agroforestry systems (AFS) are regarded as desirable land-use practices that improve soil carbon sequestration. However, most studies assume a positive correlation between above ground and below ground carbon without considering the effect of past and current land management, textural variations (silt and clay percentage), and such other site-specific factors that have a major influence on the extent of soil C sequestration. We assessed SOC stock at various depths (0–10, 10–30, 30–60, and 60–100 cm) in shaded perennial coffee (Coffea arabica L.) AFS in a 17-year-old experimental field at the Centro Agronómico Tropical de Investigación y Enseñanza, (9°53′44′′ N, 83°40′7′′ W; soil type: Ultisols and Inceptisols, Turrialba, Costa Rica. The treatments included coffee (Coffea arabica L.) grown conventionally (with chemical fertilizers) and organically (without chemical fertilizers) under two shade trees, Erythrina poeppigiana (Walp.) O.F. Cook., and Terminalia Amazonia J.F.Gmel., Sun Coffee (Coffea arabica L.) (Sole stand of coffee without shade), and Native Forest. Three replicated composite soil samples were collected from each system for each depth class, and SOC stocks in three soil aggregate fractions (2000–250 µm, 250–53 µm, and <53 µm) and in the whole soil determined. The total SOC stocks were highest under forest (146.6 Mg C ha⁻¹) and lowest under sun coffee (92.5 Mg C ha⁻¹). No significant differences were noted in SOC stock within coffee AFS and sun coffee across fraction sizes and depth classes. Organic management of coffee under heavily pruned E. poeppigiana, with pruned litter returned to soil, increased SOC stocks for 0–10 cm depth soil only. High input of organic materials including pruned litter did not improve SOC stocks in deeper soil, whereas variations in silt and clay percentages had a significant effect on SOC stocks. The study suggests that high amounts of aboveground biomass alone are not a good indicator of increased SOC storage in AFS, particularly for soils of sites with historical characteristics and management similar to this study.

Crop health management systems can be designed according to practices that help to reduce crop losses by restricting pathogen development and promoting host plant growth. A good understanding of pathogen and host dynamics, which are interdependent, is therefore needed. In this article, we used a holistic approach to explain the behavior of coffee leaf rust (CLR), a major coffee disease. We monitored coffee plant and CLR dynamics simultaneously in plots under different disease management and agroforestry systems. Diseased leaves were also collected to characterize inoculum stock and rust life stages (latent rust area, area with uredospores, necrosis due to rust) through picture analysis. We used structural equation modeling to obtain an overview of CLR pathosystem functioning on a plant scale. This overview integrates processes such as disease dilution by host leaf renewal, direct and indirect effects of fruit load on CLR development, antagonistic effects of shading depending on rust life stages, the tonic effect of copper-based fungicides on leaf retention, and effects on rust life stages depending on fungicide types. From our results, we also deduced that the inoculum stock could be calculated in unsprayed plots from the rust area with uredospores, with uredospores at 58 × 10³ cm⁻², on average.

Los frutales en la región norte de la Amazonía se encuentran como parte de la diversidad de cultivos en las chakras de los productores. El objetivo del presente estudio fue caracterizar los frutales amazónicos presentes en las fincas productoras de cacao, café y sistemas silvopastoriles ubicadas en las provincias de Orellana y Sucumbíos La información se obtuvo en base a encuestas dirigidas y mediante observación directa en el campo. Los resultados indicaron que en las dos provincias, los productores establecen de 1 a 19 especies de frutales en sus parcelas, siendo las fincas de menos de 10 hectáreas las más diversas. En la mayoría de fincas, los frutales predominantes en los sistemas de producción son cítricos, coco, guaba, aguacate, papaya, piña y chonta. Estos cultivos se encuentran en asocio con café, cacao, sistemas silvopastoriles; monocultivos; o dispersos fuera de estos sistemas. Por otro lado, se han introducido especies que son consideradas como frutales con potencial de mercado, entre ellos se encontraron la grosella, higo, pomelo, mango y maracuyá. La producción de los frutales está destinada en su mayoría para autoconsumo y alimentación de los animales de la finca; sin embargo el excedente se vende para generar un ingreso económico.

O objetivo deste trabalho foi avaliar a diversidade de plantas invasoras, em sistemas agroflorestais com cafeeiros (Coffea arabica L.) e em cafezal a pleno sol, sob manejo orgânico e convencional. Foram avaliados 20 tratamentos no delineamento de blocos ao acaso, em parcelas subdivididas no tempo, com três repetições. Os tratamentos corresponderam à combinação entre sistemas agroflorestais e quatro níveis de manejo, baseados na intensidade das práticas e aplicação de insumos: alto e médio convencional, médio e baixo orgânico. Em julho de 2002 e setembro de 2005 foi realizado o levantamento de plantas invasoras. Determinaram-se a riqueza, abundância, diversidade e eqüitabilidade. Observou-se redução nos valores médios de riqueza, abundância, diversidade e eqüitabilidade, em que os menores valores foram encontrados no tratamento com manejo alto convencional. Houve redução na freqüência das trepadeiras, ciperáceas e espécies de folhas estreitas (má cobertura), e aumento das espécies de folhas largas (boa cobertura) e gramíneas. Nas duas épocas, os maiores percentuais de pontos com solo descoberto foram encontrados no tratamento alto convencional, e os menores percentuais foram encontrados em todos os tratamentos com manejo médio e baixo orgânico, e em três dos sete tratamentos com manejo médio convencional. Tais resultados demonstram que onde há aplicação freqüente de herbicida, a presença de árvores não evita exposição do solo.

Objetivou-se, neste estudo, determinar se as populações das minhocas são alteradas em função do manejo do café (Coffea arabica) em Turrialba, CostaRica. Os seguintes sistemas de cultivo do café foram estudados: a pleno sol (PS) e sombreado com eritrina, Erythrina poeppigiana (E); terminalia, Terminalia amazonia (T) e cashá, Chloroleucon eurycyclum (Ab). A hipótese foi de que o manejo orgânico do café e o fornecimento da serapilheira de melhor qualidade favoreceria a diversidade, a densidade e a biomassa das minhocas. As populações das minhocas foram alteradas, em função do manejo com insumos sintéticos ou orgânicos , sendo a densidade menor no café a pleno sol. Entre as espécies utilizadas no sombreamento, a eritrina parece limitar a abundância das minhocas. Contudo, favorece a diversidade das mesmas, tendo sido registradas duas espécies de minhocas com papéis ecológicos diferenciados, Pontoscolex corethrurus, endogeica e Metaphire californica, anécica; ao contrário dos demais tratamentos, onde somente foi encontrada a primeira espécie, considerada cosmopolita com distribuição pantropical.