Effect of Intercropping on Purple Blotch (Alternaria porri) of Onion (Allium cepa L.)

Abstract

Onion (Allium cepa L.) is a biennial bulb crop, produced all over the world. It is attacked by many diseases, out of which Purple blotch of onion caused by Alternaria porri (Ellis) Neerg causing heavy yield loss in both bulb production and seed production. Native Bacillus were isolated from the rhizosphere of vegetables and ornamental crops of the SHUATS campus and were identified through bio-chemical tests. In vitro the Bacillus isolates were screened for antagonism on Alternaria porri by dual culture technique. The growth of A. porri was recorded at 48, 72 and 96hrs after incubation and found that all the six isolates tested significantly inhibited the growth of A. porri as compared to the control. For seedlings preparation Nashik red variety were grown in nursery bed in the garden, Department of Plant Pathology and then 28days old plants were transplanted to the field in 2×2 m plots. Seven days after transplanting microalgae was applied @ 3kg /ha through irrigation and after45days 2nd application of the same dosage of microalgae was given and isolates of Bacillus spp. was sprayed @ 1.71 × 108 c.f.u/ml. Results showed that all the treatments significantly reduced the disease intensity as compared to control.