Abstract:
Leaf spot is an important foliar disease of date palm (
Phoenix dactylifera L.) because infection reduces healthy leaf area and may adversely affect plant vigour and productivity. In the present investigation,
Alternaria alternata associated with leaf spot symptoms of date palm was isolated, purified and identified on the basis of cultural and morphological characteristics, and its pathogenicity was confirmed on healthy date palm seedlings. The efficacy of six fungicides, viz., Captan 50% WP, Chlorothalonil 75% WP, Copper oxy-chloride 50% WP, Carbendazim 50% WP, Propineb 70% WP and Mancozeb 75% WP, was evaluated against the pathogen under in vitro conditions using the poisoned food technique on Potato Dextrose Agar. The experiment was conducted in Completely Randomized Design with three replications. Copper oxy-chloride 50% WP was the most effective treatment, recording the minimum mean colony diameter of 5.00 mm and maximum mycelial growth inhibition of 94.44%. Captan 50% WP ranked second with 17.00 mm colony diameter and 81.11% inhibition, followed by Propineb 70% WP (79.63%) and Mancozeb 75% WP (77.04%). Chlorothalonil 75% WP and Carbendazim 50% WP recorded 66.30 and 64.07% inhibition, respectively, whereas the untreated control recorded 90.00 mm colony growth. Under the conditions of the present experiment, copper oxy-chloride, Captan, Propineb and Mancozeb were the most promising treatments and warrant further field-level evaluation against date palm leaf spot.
