Effect of urea on microbial degradation of apple leaf litter and its relationship to the inhibition of pseudothecial development of Venturia inaequalis

Abstract

A study was undertaken during 1994-96 on the effect of urea treatment in suppression of perfect stage of Venturia
inaequalis. Application of urea @ 5% at leaf abscission on scab affected leaves indicated that besides accelerating
litter decomposition of fallen leaves, it also encouraged the microbial population. As many as 59 micro-organism were
isolated and identified from the urea treated leaf litter, The activity of B potential fungal antagonists was tested for
biological control of V. inaequalis (Cke.) Wint. The effect of Athelia sp. alone at high altitude and along with urea at low
altitude, Chaetomium globosum Kunze and Schm. at both the locations and treatments and C. olivaceum Cooke and Ell.
acted exclusively at low altitude. These resulted in significant reduction in the pseudothecial initials and production
of asci and ascospores. The present study thus indicated the potential of microbial antagonism to the perfect stage
of the V. inaequalis for biocontrol in nature by adopting pre-leaf fall spray of urea essential in an integrated programme for
apple scab control.