Studies on the effect of mycorrhization of potato roots on the hatching activity of potato root leachate towards the potato cyst nematodes, Globodera pallida and G. rostochiensis

Successful mycorrhization of potato plants cv. Golden Wonder was achieved with three commercial preparations of arbuscular mycorrhizal fungi (AMF): Vaminoc (mixed-isolate inoculum) and two of its components, Glomus intraradices and Glomus mosseae. Potato cyst nematode hatching assays were conducted on the potato root leachate (PRL) produced by inoculated and non-inoculated potato plants to examine the effect of AMF inoculation on the hatching response of the two PCN species, Globodera rostochiensis and G. pallida. The overall hatch response of G. rostochiensis to the potato root leachate was greater than G. pallida. Root leachates from Vaminoc- and G. mosseae-inoculated plants were found to stimulate the hatch of G. pallida in the first 3 weeks after shoot emergence. Fractionation of root leachates with standardised carbon content by Sephadex G-10 chromatography revealed multiple AMF effects on hatching factor (HF) production. Root leachates from Vaminoc-inoculated plants contained markedly more G. pallida-active HF than all other treatments; by contrast, PRL from the three AMF treatments exhibited little variation in the quantity of G. rostochiensis-active HF produced. Several HF were PCN species-specific or species-selective, with those resolved from the G. intraradices and G. mosseae PRL profiles exhibiting an apparent preference for G. rostochiensis rather than G. pallida. Mycorrhization also significantly increased the root dry weight of plants.