Maharashtra ranks first in production of onion. Purple blotch [Alternaria porri (Ellis) Cif] is one of the severe onion diseases in Maharashtra causing higher yield losses. Chemical fungicides are effectively used to manage it, are responsible for environmental hazard and fungicidal resistance in the pathogens and sustainability of onion production. Oligochitosan is a deacetylated derivative of chitin obtained by gamma irradiation of chitosan. Present study was conducted to assess the effect of oligochitosan on management of purple blotch of onion. The best management of the disease was observed when three sprays of chitosan (oligochitosan) 200 ppm were given at 30, 45 and 60 days after transplanting. The results indicated that there was highest yield in this treatments . t ha-1 as compared to control (water spray) . t ha -1 . The disease intensity was minimum ( PDI) as compared to control treatment (water spray) of PDI as well as in the form of AUDPC values. Thus the study indicated that there was t ha-1 yield improvements in onion with minimum purple blotch disease by foliar application of oligochitosan. Thus it can be used as potential antifungal agent for the management of other diseases in different crops which will help for sustainable agriculture. | Oligochitosan as an effective modulator to manage the yield and productivity of onion infected by Alternaria porri
