Biology, epidemiology

Pseucercospora fuligena diseased plants and plant survives on debris, in its mycelial form or through its conidia that can keep for more than 18 months. It would affect weeds like Solanum nigrum which would allow it to stay in or near crops. The same would be true for various other Solanum spp. and Capsicum spp.

Contaminations are rapid during wet periods, via the stomata. Humidity levels of at least 85% are needed for the spores to germinate in 5 hours. The germ tubes enter through the stomata.

Once in place in the tissues, the fungus sporulates abundantly (figure 1), producing a velvety black conidium made up of more or less brown conidiophores, partitioned and measuring 3.5-5 x 25-70 µm (figure 2). They bear subhyaline conidia with several septa and measuring 3.5-5 x 15-120 µm (Figure 3). The conidia are then dispersed by the wind over long distances, and by splashing water following rain or sprinkler irrigation. They are also affected by the workers and their tools.

The Sigatoka agent develops in the presence of water on plants and during prolonged periods of humidity (rain, dew, fog, etc.). Its thermal optimum is around 27 ° C.