ASSESSMENT OF in vitro PATOGENICITY OF Purpureocillium lilacinum ON Globodera rostochiensis

Abstract

Due to the high density of the golden nematode of Potato Globodera rostochiensis in the mountainous region of the Cofre de Perote, parasitic fungi in the different stages of this pest are being searched for. The aim of the study was to isolate fungi associated to the second juvenile stage (J2) of Globodera rostochiensis on potato, sown in the Cofre de Perote region of Veracruz, Mexico and to evaluate the pathogenicity in vitro of one of the strains on eggs as well as J1 and J2 juveniles of G. rostochiensis. J2 of the golden nematode specimens were extracted from 10 soil samples (500 cc) by the Baerman method. Individually 300 J2 were placed on 8 mm discs with agar and malt extract to allow the growth of the fungi. A total of 16 fungi strains were obtained (5.3%) associated to J2. The isolated fungi were Aureobasidium (3), Cladosporium (2), Fusarium (3), Pestalotiopsis (3), Penicillium (4) and Purpureocillium lilacinum (1). This last one was selected to study the infection process and evaluate its pathogenicity on the eggs and J1 and J2 juveniles of the golden nematode. Germination spores of P. lilacinum were observed 12 hours after inoculation. The development of the mycelium on the inside and outside of the J2 after 72 hours and the formation of conidiophores at 96 hours were observed.