Effect of pokeweed (Phytolacca americana L.) extract on hatching of Globodera rostochiensis and Meloidogyne spp.

Abstract

The effect of pokeweed fruit extract on hatching of the potato cyst nematode, Globodera rostochiensis, and the British root-knot nematode, Meloidogyne artiellia, was studied in Italy under laboratory conditions at 20 ± 1 °C. Cysts of G. rostochiensis were exposed to a series of increasing pokeweed fruit extract aliquots of 0.01, 0.02, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8 and 1.0 ml, which were added to 3 ml of sodium metavanadate 0.6 mM. Egg masses of M. artiellia were exposed to the same series of increasing fruit extract aliquots that were instead added to 3 ml of water. Controls were the hatching agent sodium metavanadate 0.6 mM, pokeweed root leachate and an aliquot of 1 ml of pokeweed fruit extract added to 3 ml of water for G. rostochiensis, and distilled water only for M. artiellia. The control treatment sodium metavanadate induced 20.7% hatching of G. rostochiensis, whereas the other two controls, pokeweed root leachate and 1 ml fruit extract in 3 ml of water, did not induce any hatching. The hatching of G. rostochiensis was not enhanced by adding to sodium metavanadate aliquots of 0.01-0.05 ml of pokeweed fruit extract, but was significantly increased by adding larger aliquots of 0.1-0.8 ml and suppressed (7.2%) by 1 ml. The greatest hatch increase of G. rostochiensis (81.6%) was provided by adding an aliquot of 0.4 ml of pokeweed fruit extract to 3 ml of sodium metavanadate. Hatching of M. artiellia was of 80.5 % in the control distilled water alone and was not enhanced by adding 0.01-0.2 ml of pokeweed fruit extract. However, water enrichment with increasing aliquots of 0.4-1 ml fruit extract significantly suppressed (17.5-37.7%) M. artiella hatching compared to the control. Pokeweed was a very good host for M. incognita and M. javanica and a non-host for M. artiellia.