Investigation on the Diseases of Betelvine and Their Contro

Abstract

Betelvine (Piper betle L.) ,an important cash crop is grown on a commercial scale in Karachi, Thatta districts of Sindh and Hub region of Balochistan. Pakistan also imports a major portion of betel leaves for its consumers like Bangladesh, India, Sri Lanka and Thailand spending more than Rupees two hundred million in foreign exchange. The shady and moist atmosphere of conservatories where the betelvine is grown favours the development of many diseases that greatly affect the growth of plants and produce heavy losses to the farmers. A survey of betelvine fields in Karachi and Thatta districts of Sindh and Hub area of Balochistan was conducted during June 1996 to July 1999 where 41 species belonging to 25 genera of fungi, and 12 species belonging to 10 genera of plant nematodes were isolated and identified. Of the fungi isolated, 28 fungi appear to be new records on betelvine in Pakistan. Similarly, nine nematode genera viz., Aphelenchoides, Aphelenchus, Heliocotylenchus, Hoplolaimus, Longidorus, Pratylenchus, Rotylenchulus, Tylenchorhynchus and Xiphinema appeared to be new records to be new records on betelvine from Pakistan. Artifical inoculation of betelvine leaves of leaf discs with Fusarium Semitectum, F.solani, F. sporotrichoides, Bipolaris australiensis, B. hawaiiensis, B. papendorfi Curvularia. C. pallescens, C.tuberculata, Exserohilum rostrata and Botryodiplodia theobrome produced necrotic spots F.solani, F. sporotrichoides, Bipolaris australiensis, B. hawaiiensis, B.papendorfii, Curvularia pallescens, C. tuberculata and botryodiplodia theobrome appear to be new leaf spot pathogens of betelvine not hitherto reported. Use of Benomyl or Topsin-M showed significant reduction in leaf spot and anthracnose diseases wheras Furadan was found effective in the control of root-knot nematode. Soil treatment with Furadan and spray of Banomyl or Topsin-M on plants reduced root rot and root-knot disease complex resulted in increase in yield. Of the various microbial antagonists, Paecilomyces lilacinus, Pencilium sp, Trichodermia harzianum, T.koningii, T. viride, Bacillus subtilis, Bradyrhizobium japonicum, and Rhizobium meliloti inhibited growth of F.solani, F. sporotrichoides, R.solani and/or M.phaseolina. Soil application of rice grain culture of P.lilacinus provided significant decrease in nematode and fungal infection resulting in increased yield. The efficacy of P. lilacinus was not significantly different from that of Furadan.