Chemical Control of Guava Die-Back and Response of Guava Cultivars to the Disease in Egypt

Abstract

Guava (Psidium guajava L.,) die-back disease caused by Botryodiplodia theobromae Pat., is a destructive disease, considered one of the most important and economic disease of guava. Amistar Top 325-32.5% E.C. gave the highest decreasing of linear growth and amount of growth of isolate code No., Q.K.4., followed by Camzin 50% W.P., Monceren 25% W.P. and Montro 30% E.C. Meanwhile, Ridomil Gold/Plus 42.50% W.P., Copral 50% W.P., Eminent 12.50% E.W. and Thiovat Jet 80% W.G. exhibited a lowest effect in reducing of linear growth and amount growth of B. theobromae isolate code No., Q.K.4. Amistar Top 325-32.5% E.C. was the most efficient fungicide in reduce disease incidence and disease severity infield of B. theobromae isolate code No., Q.K.4., followed by Camzin 50% W.P., Monceren 25% W.P., Montro 30% E.C. Meanwhile, Ridomil Gold/Plus 42.50% W.P., Copral 50% W.P., Eminent 12.50% E.W. and Thiovat Jet 80% W.G. showed a lowest efficient in reducing the disease incidence and disease severity. Soil drench method of fungicides application was the higher efficient method in elimination of percentage of disease incidence and disease severity followed by foliar spray application, relatively. Banaty transplant was the most susceptible cultivar to the all tested B. theobromae isolates, whereas cultivar Gizy Ahmr was the lowest susceptible with the same isolates, information about cultivar reaction of guava transplants against B. theobromae is still scanty.