Suppression of Basil Downy Mildew Caused by Peronospora belbahrii using Resistance Inducers, Mineral Salts and Anti-transpirants Combined with Different Rates of Nitrogen Fertilizer under Field Conditions

Pathological and physiological studies of Downy Mildew of Basil (Ocimum basilicum) Caused by Peronospora belbahrii in Egypt

“…Light microscopy revealed that while dichotomously branched sporangiophores with abundant spores were formed in the dark, abnormally branched sporangiophores, with no spores, were formed under light conditions where a degree of 12h /12h was recorded as the best light and dark hours, due to the fact that germination of sporangia needs darkness, while sporangiophores need light periods. This result agreed with [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33].…”

“…Sporangia were harvested with a small paintbrush from the lower surface of basil leaves in a petri dish containing cold sterilized distilled water.1ml of P. belbahrii 1x10 5 sporangia suspension was put in cavity slides on 9 mm plastic plates. Plates were immediately placed into incubation chambers maintained at 10,12,14,16,18,20,22,24,26, and 28°C in darkness. Incubation chamber temperatures were confirmed using analog thermometers.…”

“…Temperature is an important environmental factor that influences the germination of sporangia. The sporangia of P. belbahrii were incubated at 10,12,14,16,18,20,22,24, and 28 ºC for 24 hours in sterile distilled water. Data in Table (4) and Fig.…”

“…The disease emerged in Switzerland in 2001 [6], Italy in 2003 [8], France and Belgium in 2004 [9][10], South Africa and Malta in 2005 [11], Iran in 2006, Cameroon 2007 [12] and the United States in 2007 [13-14-15], Argentina in 2008, Cuba and Taiwan in 2009, Hungary and U.K. in 2010 [16][17], Israel and Canada in 2011 [18][19]., and the Czech Republic in 2012 [20], Currently, BDM occurs in all parts of the world where sweet basil is grown. In Egypt basil downy mildew, incited by P. belbahrii Thines, was observed for the first time especially in Beni Suef governorate in 2013 [21] it has become a serious disease in sweet basil and the rapid spread of the pathogen P. belbahrii throughout various herb production regions causing complete crop losses [22].…”