STATUS OF POMEGRANATE DISEASES OF NORTHERN KARNATAKA IN INDIA

Pomegranate (Punica granatum L.) is one of the important fruit crops in arid and semi-arid regions of Karnataka. The area under pomegranate is fast dwindling due to onslaught by a number of diseases such as bacterial blight, anthracnose, wilt and dieback or decline. Bacterial blight of pomegranate caused by Xanthomonas axonopodis pv. punicae has assumed epidemic proportions (40-85% severity) in northern Karnataka (Bijapur, Bellary, Bagalkot) seriously threatening its cultivation. On leaves small, water soaked, brown to dark brown spots appear while on fruits oily, dark brown to black spots with L or Y shaped cracks are formed. The pathogen survives in fallen leaves and fruits during off-season and spreads through planting material, cutting secateurs and wind splashed rains. Temperatures around 31.8-35.6°C with enough rainfall during July-October were found to favor disease development. Pruning in September-October, hastabahar cultivation and rest period are highly beneficial to pomegranate plants and suppress the pathogen. Spraying Bacterinashak or streptocycline (500 ppm) + copper oxychloride (2000 ppm) has been found most effective. Pomegranate wilt (Ceratocystis fimbriata) has been the most important disease in Karnataka and Maharashtra. Symptoms include yellowing of the leaves, epinasty and sudden wilting. The pathogen spreads through infected seedlings, sanitation measures such as removal and destruction of affected trees, soil sterilization with formalin (20 ml/L) check the disease. Pomegranate decline also referred to as wilt, involves poor soil and water management practices. Use of heavy and ill drained soils, close planting, excessive irrigation and fertilizers predispose the plant for disease complex. Rhizoctonia bataticola, Fusarium solani and root knot nematode as well as shot hole borer management includes soil drenching with propiconazole (0.1%) + boric acid (0.5%) + phosphoric acid (0.5%). Anthracnose of pomegranate caused by Colletotrichum gloeosporioides is most serious during the period July-October. The disease appears as small, regular to irregular black spots on leaves, calyx region and fruits which turn later on as dark brown depressed spots. Rains, high humidity and temperatures of 20-27°C favor the disease, management through carbendazim/ difenconazole or thiophanate methyl at 0.1% or chlorothalonil 0.2% sprays at fort-nightly intervals have been found effective. The minor diseases of pomegranate which appear occasionally in mild to less severe form include Alternaria blight, leaf spots due to Cercospora, Sphaceloma, Fusarium, Phomopsis, Drechslera, Phytophthora nicotianae and canker (Ceuthospora phyllosticta) as well as fruit spots and rots.