Local dynamics of the coffee rust disease and the potential effect ofshade

In this paper we present a mode that incorporates two levels of dynamic structuring of the coffee rust disease (caused by the rust fungus, Hemileia vastatrix). First, two distinct spatial scales of transmission dynamics are interrogated with respect to the resultant structure of catastrophic transitions BLOCKIN BLOCKIN of BLOCKIN BLOCKIN epidemics. BLOCKIN BLOCKIN BLOCKIN BLOCKIN Second BLOCKIN BLOCKIN the BLOCKIN BLOCKIN effect BLOCKIN BLOCKIN of BLOCKIN BLOCKIN management BLOCKIN BLOCKIN style, BLOCKIN BLOCKIN especially BLOCKIN BLOCKIN the BLOCKIN BLOCKIN well-­‐known BLOCKIN BLOCKIN issue BLOCKIN BLOCKIN of shade management, is added to the base-­‐line model. The final structure includes a simple one-­‐to-­‐one functional structure of disease incidence as a function as well as a classical critical transition structure, and finally a hysteretic loop. These qualitative structures accord well with the recent history of the coffee rust disease. Coffee is reported to be one of the most traded commodities in the world, (Pendergast, 1999) and the base of economic support for millions of small farmers (Bacon, 2004) and many national economies. The coffee rust disease (Ccaused by the rust fungus, Hemileia vastatrix) BLOCKIN