Studies on the Management of Pestalotiopsis Leaf Spot of Onion (Allium cepa L.) with Phytoextracts

Pestalotiopsis leaf spot is a disease of onion prevalent in Manipur. Evaluation for antifungal properties of ten locally available phytoextracts on onion leaf spot through in vitro Poisoned Food Technique revealed that Garlic extract showed the maximum fungistatic property at 5 and 7% concentrations. Phlogacanthus, Turmeric, Sweetflag and Ginger showed maximum antifungal property at both 15 and 20%. In Potato Dextrose broth also, Garlic showed maximum inhibition at 5 and 7% concentrations, but at 15%, Ginger showed maximum inhibition followed by Turmeric and Sweetflag. However, at 20%, Turmeric showed maximum inhibition followed by Ginger and Sweetflag. Acervuli formation was maximum and highly favoured by the extracts of Wildsage and Sweetflag. In vivo studies revealed that Mancozeb @ 0.2% was the most effective with highest bulb yield (13.89 t/ha) followed by Garlic (12.93 t/ha), Turmeric (12.26 t/ha), T. harzianum (12.17 t/ha) and Ginger (12.09 t/ha). Due to antifungal properties of Garlic, turmeric and ginger, they show as much efficiency as fungicides and Trichoderma.