Effect of irrigation regimes on disease expression in melon plants infected with Monosporascus cannonballus

The effect of irrigation regimes on disease expression in melon plants infected with Monosporascus cannonballus was studied during two summer growing seasons (1998 and 1999) in the Arava region of southern Israel. Less frequent and reduced irrigation postponed the onset of plant collapse and lowered disease incidence. Delaying disease development in infested fields by reducing irrigation frequency allowed crop harvest before plant collapse. However, reduced irrigation regimes reduced yields, as shown in methyl bromide fumigated plots. Fruits from melon plants grown under reduced irrigation in the infested plots were also of lower quality due to water shortage. The delay in plant collapse under the reduced irrigation treatments was attributed to a combined effect of reduced fruit load and the development of a deeper root system, which could support the increased water demand of the mature, fruiting plant.