THE ROLE OF BETAINES IN ALKALINE EXTRACTS OF ASCOPHYLLUM-NODOSUM IN THE REDUCTION OF MELOIDOGYNE-JAVANICA AND MELOIDOGYNE-INCOGNITA INFESTATIONS OF TOMATO PLANTS

Soil application to the roots of tomato plants (Lycopersicon esculentu m cv. Ailsa Craig) of a commercially available alkaline extract of the brown alga, Ascophyllum nodosum, resulted in a significant reduction in the number of second stage juveniles of both Meloidogyne javanica a nd M. incognita invading the roots, compared to those of plants treate d with water alone. Egg recovery from the seaweed extract treated plan ts was also significantly lower. The three major betaines found in the seaweed extract (gamma-aminobutyric acid betaine, delta-aminovaleric acid betaine and glycinebetaine), when applied at concentrations equiv alent to those in the extract, also led to significant reductions in b oth the nematode invasion profile and egg recovery. This led to the co nclusion that the betaines present in the seaweed extract play a major role in bringing about the observed effects. Application as a soil dr ench of the inorganic constituents of the extract also resulted in sig nificant reductions in egg recovery, but these reductions were not so pronounced as those produced by application of the betaines.