In-vitro Evaluation of Trichoderma Species and Some Selected Botanical Extracts against Alternaria helianthi (Hansf) Causing Alternaria Blight of Sunflower

This study investigates the in vitro efficacy of bioagents and selected botanicals in managing Alternaria helianthi, the pathogen responsible for Alternaria blight in sunflower (Helianthus annuus L.). Two bioagents, Trichoderma harzianum and Trichoderma viride, and six botanicals—Azadirachta indica (neem), Lantana camara (lantana), Curcuma longa (turmeric), Aloe barbadensis (aloe vera), Withania somnifera (ashwagandha), and Mentha spicata (pudina)—were evaluated using the dual culture and poison food technique, respectively. The results showed that T. harzianum exhibited the highest inhibition of mycelial growth at 76.32%, while neem extract was the most effective among botanicals, achieving a maximum inhibition of 75.03% at 15% concentration. These findings suggest the potential of bioagents and botanicals in eco-friendly management strategies for Alternaria blight in sunflower cultivation.