Potential of microorganism as biological control agents of selected plant pathogens [Philippines]

• Main Author: Molina, G.C
• Format: Publication
• Language: English
• Published: College,Laguna (Philippines) 01.10.1985
• Subjects: ASPERGILLUS; CONTROL BIOLOGICO; FILIPINAS; LUTTE BIOLOGIQUE; ORGANISMOS PATOGENOS; PATHOGENE; PENICILLIUM; PHILIPPINES; TRICHODERMA

Trichoderma viride, Penicillium sp., and Aspergillus niger showed antifungal activities against the fungal pathogens studied. Growth inhibition in dual cultures and improved seed germination resulted from treatments with either spore suspension or culture filtrates of the test organisms. Culture filtrate was more effective. Antifungal activities of these organisms were comparable to the standard fungicide, Vitavax 75 WP. Colonies of Pseudomonas solanacearum were also drastically reduced by the test antagonist, namely: Aspergillus niger, Aspergillus parasiticus, Penicillum sp., Penicillium oxacilum, and Trichoderma viride. Spore suspension and culture filtrates of these organisms but not the pure extracts were suppressive to the bacterium in plate cultures. However, their effects on the control of the bacterial wilt disease on the tomato plants grown in pots under greenhouse conditions were not observed. Sixteen microorganisms were evaluated for biological activity against the nematodes Meloidogyne incognita on tomato and Radopholus similis on banana. Spore suspension, culture filtrate, crude extracts and pure extracts of the test antagonists showed activities against the nematodes. Paecilomyces lilacinus was active when applied as spore suspension, while Penicillium anatolicum, Aspergillus niger and Penicillium sp. exhibited high degree of nematicidal activities when applied as culture filtrate, crude extract and pure extracts. A method of extraction and purification of extracts from biologically active microorganisms was described. Pure extracts from Penicillium oxalicum showed uv absorption maxima at 217 nm; Penicillium anatolicum with 204 nm; Aspergillus niger with 212 nm; and Penicillium sp. with 208 nm. Infrared analysis indicated general similarities of the four extracts. Combined analysis of spectral data indicate that the compounds are structurally related and showed the general characteristics of ketone and carbonyl groups