Silicon Reduces Black Sigatoka Development in Banana

Abstract

The effect of silicon (Si) uptake on the susceptibility of Musa acuminata to Mycosphaerella fijiensis was investigated in three experiments conducted under controlled conditions. Plants were grown in the presence of Si or not, in pots adapted for a hydroponic culture system or in pots filled with compost. The banana leaves were inoculated after 4 or 6 months of plant growth by spraying conidial suspensions or by brushing mycelia fragments. The disease progress over time was assessed using quantitative and qualitative scales. At the end of each experiment, disease severity was also analyzed using the image analysis software ASSESS. The Si concentration in the leaves of plants supplied with Si reached 10 to 28 g/kg of dry matter. The first symptoms appeared 18 days after inoculation. The disease developed more rapidly and more severely on banana plants grown without Si than on plants supplied with Si. The areas under the disease progress curve (AUDPCs) calculated for plants grown with Si were significantly lower than the AUDPCs for plants not supplied with Si, regardless of inoculation method. Thus, Si supply could be a valuable tool in integrated pest management against M. fijiensis by reducing the disease pressure on banana.