Use of Three Synthetic Fungicides to Reduce the Incidence of Ascochyta Blight (Ascochyta rabiei) in Chickpea (Cicer arietinum L.): A Susceptible Cultivars Case

Abstract

This study examined the effect of three synthetic fungicide, maneb “Manebe80®” chlorothalonil “Bravo®” and azoxystrobin “Ortiva®” on the incidence of ascochyta blight (AB) of chickpea caused by Ascochyta rabiei using three chickpea germplasm (ILC482, ILC484 and Flip 1025). The results, statisticaly reliable (C.V. less than 20%), indicated the in vitro test of chemical control has significant effect at P0.01, on the mycelial growth of pathogen. All three fungicides caused important MGI% (Mycelial growth inhibition rate), which varied between 30 and 66%. There was a significant action induced by chlorothalonil fungicide (54 – 65%), followed closely by azoxystrobin (46 – 63%) and maneb (30 – 65%). In the in vivo test of chemical control for AB incidence by detached leaves showed a remarkable percentage of reduction in the severity of ascochyta blight varied between 20 and 80%. We noticed that the systemic fungicide like azoxystrobin can reduce the ascochyta blight severity (RDS%), with ranging between 71 and 80%, for other two contact fungicides (chlorothalonil and maneb), the mycelia growth inhibition rate was close to 50% (from 20 to 47%). These results indicated that the systemic fungicides, like azoxystrobin, have a significantly reduced the incidence and development of ascochyta blight disease in the susceptible cultivars (ILC1929, ILC263 and ILC484).