Preliminary trials with extracts of Quillaja saponaria Molina for the control of root-knot nematodes

Five different experimental trials, four under field conditions and one in greenhouse, were undertaken in different regions of Italy to ascertain the nematicidal effect of extract of Quillaja saponaria on Meloidogyne incognita in tomato, cantaloupe and tobacco. Quillay extracts were applied at the rates of 15, 23 and 31 l/ha, distributed in 5-20 l of water/square m by drip irrigation. Non-treated plots and plots treated with the chemicals 1,3-D 97, fenamiphos, fosthiazate or oxamyl were used as controls. Quillay extract significantly increased tomato yield and reduced nematode population only at the rate of 23 l/ha in the field at Monteroni (Lecce province), Southern Italy, and at all application rates in the field experiment at Monticelli di Mesola (Ferrara province), Northern Italy. No significant increase of cantaloupe or tobacco yield or reduction of root gall index was found in the field experiments in Central Italy. The trial on tomato in greenhouse at Castellaneta (Taranto province) resulted in significant yield increase and suppression of M. incognita population, compared to untreated soil, at all extract rates, with significant difference between plots treated with quillay and 1,3-D 97. Quillay extract showed potential for the control of root-knot nematodes on tomato, but further investigations are still necessary to ascertain the best rate and time of application