Eco-friendly Management of Purple Blotch (Alternaria porri) of Onion (Allium cepa L.)

Onion (Allium cepa L.) is one of the important commercial vegetable crops grown in India. Onion is attacked by many diseases, one of which is Purple blotch. This study aimed to evaluate the effect of organic manures and fungicides on Purple blotch disease of onion caused by Alternaria porri. The research work was undertaken at Central Research Farm (CRF) Sam Higginbottom University of Agriculture, Technology and Sciences, SHUATS, Naini, Prayagraj during Rabi in 2023-24. A randomized block design with seven treatments was employed including Untreated check T0 (Control), T1 (Vermicompost @100g/m2 + Lantana camara @100g/m2), T2 (Biomix @100g/m2 + Lantana camara @100g/m2), T3 (Cocopeat @100g/m2 + Lantana camara @100g/m2), T4 (Vermicompost @50g/m2 + Biomix @50g/m2 + Lantana camara @100g/m2), T5 (Vermicompost @50g/m2 + Cocopeat @50g/m2 + Lantana camara @100g/m2) and Treated check T6 ( Carbendazim @0.2%). The results revealed that among the organic manure T4- Vermicompost @50g/m2 + Biomix @50g/m2 + Lantana camara @100g/m2 minimum disease intensity (8.21%, 17.82% and 26.48%) at 30,60 and 90 DAT, respectively while maximum disease intensity was recorded in untreated T0- Contro (12.07%, 26.54% and 39.17%) at 30, 60 and 90 DAT, respectively. Maximum plant height (17.34 cm, 29.56 cm and 38.18 cm) at 30, 60 and 90 DAT, number of leaves (4.53 per plant, 4.76 per plant and 6.66 per plant) at 30, 60 and 90 DAT, fresh weight of bulb (44.96 gm/m2), bulb diameter (5.90 cm), yield (148.30 q/ha) and benefit- cost ratio(1:4.2) were found in T4- Vermicompost @50g/m2 + Biomix @50g/m2 Lantana camara @ 100g/m2 when compared to treated T6- Carbendazim and untreated check T0- Control.