In vitro evaluation of bio-agents and botanicals against Alternaria tenuissima causing leaf spot and flower blight in marigold

Abstract:

Leaf spot and flower blight caused by Alternaria tenuissima is one of the important diseases of marigold, which causes upto 50 to 60% losses in flower yield. In this present investigation, different botanicals and bio-agents were evaluated under labouratory condition. The results revealed that, T. harzianum showed maximum (76.30%) growth inhibition of the pathogen followed by T. koningii (71.52%), T. longibrachiatum (70.13%), T. viride (69.07%), Bacillus subtilis (55.18%) and Pseudomonas fluorescens (41.85%). Among botanicals, turmeric rhizomes was found most effective showing 82.38 percent inhibition of mycelial growth of A. tenuissima followed by dhatura leaves showed 67.22 percent inhibition. Less than 50 percent growth inhibition was recorded with neem leaves (49.51%), ginger rhizomes (48.55%), ardusi leaves (35.48%), garlic cloves (30.41%) and kadvi mehandi leaves (26.08%).