Modelling in vitro mycelial growth, sporulation and spore germination of Pseudocercospora musae under different illuminance levels

Abstract

ABSTRACTBanana is one of the most produced fruits in the world. Many diseases infect the culture and yellow sigatoka is one of the most important. Light may interfere in the pre-penetration parameters of the fungus. The aim of this study was to evaluate the action of light on aspects of the life cycle of the causal agent. The action of light was tested in vitro on the mycelial growth, sporulation and germination of the fungus. For the mycelial growth 10 colonies were transferred to each Petri plate, by evaluating the green weight of a plate at each moment, in mg, at zero, 15, 21, 28, 35 and 42 days of cultivation according to different illuminance levels. Under the same conditions, the sporulation was also quantified at 5, 7, 11, 13 and 14 days. For germination, equal volumes of a spore suspension were placed in small glass containers, which then were set in mini-shades (different illuminances). Every 1h, lacto-phenol was added to a glass from each environment paralyzing the growth, at the same time, illuminance measurements were made with a light meter. The data obtained from sporulation (linear relation) and germination (positive exponential behavior) were significant for the illuminance levels tested.Significance and Impact of the StudyYellow Sigatoka disease, caused by Pseudocercospora musae, is still one of the most importante banana diseases in Brazil. Its control demands the use of fungicides. New environmental-friendly control methods should be developed. Therefore, the behaviour of both fungus and plant-fungus interaction should be known. We modelled the in vitro behaviour of P. musae in function of light intensity. Our results can help to develop shading strategies to control yellow Sigatoka.