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Incidence of dry rot of pomegranate in Himachal pradesh and its management

Sharma, R.L., Tegta, R.K.
Acta horticulturae 2011 no.890 pp. 491-499
Coniella, Hypocrea virens, Lantana camara, Melia, Mentha piperita, antagonists, carbendazim, coatings, fruits, fumigants, fumigation, fungal antagonists, fungicides, mint, orchards, pepper, plant extracts, plant fats and oils, plant rots, pomegranates, pulp, spores, surveys, weather, India
Pomegranate is highly susceptible to dry fruit rot caused by Coniella granati (Sacc.) Petrak and Sydow, and the disease has resulted in substantial losses and is threatening the upcoming pomegranate cultivation in Himachal Pradesh. The disease starts on fruits which are half grown or larger. The rot is characterized by softening of the rind and underneath pulp and seed. Ultimately the entire fruit turns brown to black after complete rotting. An extensive and comprehensive survey of various pomegranate orchards was conducted to record the incidence revealed that incidence of dry fruit rot varied from 0.55 to 22.7% with a mean incidence of 8.38% at various locations in Himachal Pradesh. The incidence was higher in Solan district where the infected fruits were often seen in the form of dark brown to black fruit mummies scattered on the orchard floor. The disease appeared maximum during the first week of August after an extended period of warm and foggy weather. Pre-harvest sprays with Bavistin and Stop among systemic fungicides gave significant control whereas, among non systemics, spray of Indofil M-45 showed some promise. Postharvest efficacy of systemic fungicides was better as protectant (pre-inoculation treatment) rather than eradicant (post-inoculation). Attempts have been made to control fruit rot with eco-friendly methods such as wrappers, fumigants, coatings, antagonists, botanicals which included plant oils and plant extracts. Fumigation with sodium or potassium meta bisulphite was superior in checking the disease. Bavistin wrappers and Nipro Fresh coating exhibited significant protection of pomegranate against dry fruit rot. Fungal antagonists, viz., Trichoderma virens, T. harzianum, T. hamatum and T. polysporium gave maximum inhibition of mycelial growth of C. granati. Antagonist protection was higher when applied at a concentration of 108 spores/ml before inoculation. 100% inhibition of mycelial growth of C. granati was obtained with citronella oil at 1000 ppm. Pre-inoculation treatment with plant extracts of darek (Melia azadirach), dedonia (Dedonia viscosa), lantana (Lantana camara) and pepper mint (Mentha piperita) provided significant control of fruit rot of pomegranate.