Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.2010.1023.1029Alternaria alternata, the Causal Agent of Alternaria Leaf Spot of Potato]]>ZakerM. MosallanejadH. 1220101321Pure methanol (m) and methanol water (mw) extracts of 5 plants namely: peppermint, eucalyptus, lavandula, Russian knapweed and datura were screened for their antifungal ability against Alternaria alternata, the causal agent of Alternaria leaf spot of potato at 5, 10 and 15% concentrations in vitro. Fungicide mancozeb 0.2% was also used for better comparison. Poisoned food technique and spore germination assay method were used to evaluate the antifungal efficacy of plant extracts. Present findings showed that methanol extracts of eucalyptus, peppermint and lavandula had impressive antifungal effects in inhibiting the mycelial growth as well as spore germination of the pathogen. It was also found that methanol extracts were quite more effective than methanol water extracts in this regard. Methanol extracts of peppermint (15%), lavandula (15%), peppermint (10%) and eucalyptus (15%) demonstrated promising ability in inhibiting the mycelial growth of A. alternata by 0.13, 0.40, 0.43 and 0.50 cm, mycelial growth respectively, while majority of methanol water extracts had either less or no effects in this connection. Spore germination of A. alternata was prominently reduced by methanol extracts, while those of methanol water extracts had very less effects in this regard. Mancozeb (0.2%), methanol extracts of eucalyptus (15%) and peppermint (10%) by 2, 6 and 7% spore germination were best, while methanol water extracts of datura 10, 15 and 5%, lavandula 15 and 10% and also Russian knapweed 5% represented no effect and by 91, 89, 87, 87, 85 and 85% spore germination were at par with control. Findings from this study confirmed that plant extracts can be used as less hazardous natural fungicides in controlling plant pathogenic fungi, thus reducing the dependence on the synthetic fungicides. Methanol extracts of peppermint, eucalyptus and lavandula might be promising materials for natural formulations in controlling Alternaria leaf spot of potato in the field.]]>Khallil, A.R.M.,20014392394Abo-El-Seoud, M.A., M.M. Sarhan, A.E. Omar and M.M. Helal,200538175184Ayoub, M. and A.U. Niazi,20011490491Bowers, J.H. and J.C. Locke,2000Fusarium oxysporum in soil and control of Fusarium wilt in the greenhouse.]]>84300305Doltsinis, S.K., E. Markellou, A.M. Kasselaki, M.N. Fanouraki and C.M. Koumaki et al.,2006Reynoutria sachalinensis, against powdery mildew of tomato (Leveillula taurica).]]>51375392Droby, S. and D. Prosky,1984Alternaria alternata: A new pathogen on stored potatoes.]]>68160161Ellis, M.B. and J.P. Ellis,1985Ershad, D.,19952nd Edn.,pp: 874-914pp: 874-914Faria, T.J., R.S. Ferreira, L. Yassumoto, J.R.P. de Souza, N.K. Ishikawa and A.M. Barbosa,2006Ocimum gratissimum L. (eugenol chemotype) against phytopathogenic fungi.]]>49867871Fawzi, E.M., A.A. Khalil and A.F. Afifi,2009Alternaria alternata and Fusarium oxysporum.]]>825902597Feng, W. and X. Zheng,2007Alternaria alternata in vitro and in vivo.]]>1811261130Hadizadeh, I., B. Pivastegan and H. Hamzehzarghani,2009Alternaria alternate.]]>6857861Harish, S., T. Saravanan, R. Radjacommare, E.G. Ebenezar and K. Seetharaman,2004Helminthosporium oryzae breda de hann, the incitant of rice brown spot.]]>4366369Hassanein, N.M., M.A. Abou Zeid, I.F. Youssef and D.A. Mahmoud,2008Azadirachta indica) and chinaberry (Melia azedarach) against early blight and wilt diseases of tomato.]]>2763772Ommati, F. and A.R. karimi,20022002pp: 3434Rai, N.K., B. Leepikatuli, K. Sharma and U.P. Singh,2000184447Schmitz, H.,19302nd Edn.,pp: 333-361pp: 333-361Shirzadian, S., H.A. Azad and J. Khalghani,200977122Simmones, E.G.,1995Alternaria, themes and variations.]]>556974Chand, H. and S. Singh,2004Alternaria brassicae (Berk.) Sacc.]]>32143144Suprapta, D.N. and K. Kalimi,2009153441