At the end of the experiment, leaf tissue samples from treated and untreated plants were collect- ed from healthy and diseased/yellowed zones for mi- crobe population determination. From each treatment 10 discs 12.56 mm2 in sizewere collected and agitated in 9 ml of water-agar (0.6 g l-1). Samples from the compost itself were also included. The samples were serially di- luted in water-agar and plated onto selective media to quantify the populations of filamentous fungi (water- agar, with 18 g l-1 agar and 50 µg ml-1 rifampicin) and cultivable bacteria (4% Scharlab tryptone soy agar with 100 µg ml-1 cycloheximide), adapted from Scheuerell and Mahaffee (2004).