In vitro antifungal activity of plant extracts on pathogenic fungi of blueberry (Vaccinium sp.)

Three pathogenic fungi of blueberry (Vaccinium spp.) responsible for dieback disease, identified as Pestalotiopsis clavispora, Colletotrichum gloeosporioides and Lasiodiplodia pseudotheobromae, were isolated in the northwestern region of the state of Michoacán, Mexico. The mycelial growth in vitro of these fungi was inhibited by extracts from Lantana hirta, Argemone ochroleuca and Adenophyllum porophyllum, medicinal plants collected in Sahuayo, Michoacán, Mexico. The extracts showed differ-ent degrees of inhibition; the most effective were: M5L extract from L. hirta and M6LFr extract from A. ochroleuca, both of which inhibited 100% of the mycelial growth of P. clavispora and C. gloeosporioides; and M4LS extract from A. porophyllum, which inhibited 100% of the mycelial growth of the three pathogens. The extracts were fractionated by thin layer and column chromatography, and the most active fractions were analyzed by gas chromatography-mass spectrometry. The major compounds identified in L. hirta extract were Phytol and α-Sitosterol. The compounds identified in A. ochroleuca were Toluene and Benzene, 1,3-bis(3-phenoxyphenoxy)-. In A. porophyllum, the compound identified was Hexanedioic acid, bis(2-ethylhexyl) ester. These results show the potential of L. hirta, A. ochroleuca and A. porophyllum as a source of antifungal compounds.