Abstract

STUDIES ON POST HARVEST DISEASES IN ONION CROP IN ANDHRA PRADESH

C. Ruth*, K. Gopal and K. Swarajyalakshmi

ABSTRACT

Onion (Allium cepa L) called as “Queen of kitchen” is one of the oldest known and an important vegetable crop grown in India. India is the second largest onion growing country in the world. Indian onions are famous for their pungency and are available round the year. Indian onions have two crop cycles, both Kharif and Rabi. The major varieties found in India are Agrifound Dark Red, Agrifound Light Red, NHRDF Red, Agrifound White, Agrifound Rose and Agrifound Red, Pusa White Round, Red-3, Red-4, local variety Bellary Red and several private sector varieties. Onions suffer from many postharvest diseases such as black mold, blue mold, neck rot, brown rot, soft rot, and smudge, among which, black mold, blue mold, and gray mold are the predominant diseases that restrict the domestic and international trade of onions. In onion, purple leaf blotch (36.5 PDI) damping off (6.0), smut (12.5), basal rot (9.5), stem elongation, cascuta and thrips are the major problems identified in Aluru, Aspari, Papile, Dhone, Kurnool,Gonegondla, Nandikotkuru mandals of Kurnool district. More per cent disease index (PDI) of Purple leaf blotch noticed in Kharif (36.5) than in Rabi (30.5) in onion crop cv. Bellary Red local variety. Onion is less perishable compared to other vegetables; however losses are inevitable during storage. It has been estimated that 40 to 50% of the production never reaches to the consumers due to postharvest losses. Due to storage losses, after harvesting the crop the quality and quantity by storage rots was affected of the produce in onion crop. Among the post harvest diseases caused by different pathogens more incidence with, Rhizoctonia, Fusariums sp., Rhizopus sp., Aspergillus sp. and Alternaia sp. were recorded and identified the pathogens. The storage losses observed in onion crop raised in Bollavaram village due to Fusarium sps, causes basal rot, the disease incidence was recorded as 20.5% in the month of January. The pathogen Aspergillus sps. causes black mold rot disease was highest in the month of December (20.4%). The purple leaf blotch disease incidence caused by Alternaria sps. Was recorded in the month of November (18.8%) in Kottala village where as in Revanur village recorded disease incidence. (19.2%). Rottening of upper surface, blackening of bulb and root portion and softening of stem portion in storage were observed.

Keywords: Onion, diseases, post harvest losses, Alternaria, Aspegillus.