EFFECTS OF EXTRACTS FROM LEAVES AND ROOTS OF Melaleuca cajuputi Powell ON NEMATODES CAUSING DISEASES ON Piper nigrum L. (BLACK PEPPER) IN VITRO

This study evaluates the effects of different extracts from leaves (fresh and dry) and roots of melaleuca on  pathogens such as Meloidogyne spp., Phytophthora spp. and Fusarium spp. which affect pepper orchards in Hau Giang province, Vietnam. The results showed that the extracts increased the rate of death of a lethal nematode (Meloidogyne spp.) on pepper up to 100%, while the natural death rate (control) only reached to58% at 3 days after stocking in vitro, and the extracts from fresh leaves had the quickest response. However, extracts from both the melaleuca fresh leaves and roots were not effective on the development of all 11 strainsof Fusarium spp. and 5 strains of Phytophthora spp. which were tested after 3 days of inoculation. The results illustrated that the extracts of dried leaves was positive against the growth of 2 strains (18%), increased thegrowth of 8 strains (73%) and ineffective on 1  strain (9%) of Fusarium spp., and completely ineffective on all 5 strains of Phytophthora spp.