PAPAYA DISEASES IN BIHAR: AN OVERVIEW

Abstract

Papaya occupies an important position among fruits grown in Bihar. Over the past two decades this crop has experienced considerable reduction in yield due to attack of various diseases. According to an estimate, yield reduction up to 50% has been observed within last 18 years. So a systematic survey was conducted during 2000-08 in different districts of Bihar viz., Samastipur, Muzaffarpur, Vaishali, Siwan, Saran, Katihar, Saharsa, and Bhagalpur to quantify losses due to major diseases of papaya in the state. During the survey two viral diseases were recorded i.e. leaf curl and Papaya ring spot virus. Leaf curl incidence varied between 12 to 27%, while PRSV incidence was most rampant showing cent per cent incidence in all the districts under the survey. Disease symptoms were some times visible in the nursery too. No variety showed tolerance/resistance against the disease. Due to severe disease incidence, area under papaya cultivation is shrinking every year. The entire papaya varieties viz. Pusa Dwarf, Pusa Nanha, Pusa Delicious, Red Lady, Coorg Honey Dew and the local ones were found susceptible. In Samastipur district, after first fruiting, all the leaves of the plant dropped due to severe PRSV attack and gradually the papaya plants succumbed to death. In some cases, papaya plants produced new tiny leaves (rosettes at the top) but affected plants produced very poor yield i.e. less than 10 kg/plant. It is very difficult to continue the crop stand even up to 2 nd year fruiting due to heavy pressure of PRSV in the state. Among fungal diseases damping off, collar rot and fruit rot, were frequently observed in all the districts under survey with varying level of incidence. Damping off disease was recorded only in nursery, while collar rot disease was recorded at various stages of plant growth. Fruit rot disease was incited by a number of fungi though Colletotrichum gloeosporioides was predominant. Fruit rot was observed at different stages of fruit growth but immature fruits were highly prone to this disease. This study may serve as a guide for planning effective management of papaya diseases in this part of the country.