Interaction between arbuscular mycorrhizal fungi and the nematicide aldicarb on hatch and development of the potato cyst nematode, Globodera pallida, and yield of potatoes

The effects of inoculation of roots of the potato (Solanum tuberosum) cv. Golden Wonder with the mixed-isolate arbuscular mycorrhizal fungus (AMF) inoculum Vaminoc, or with three single-isolates AMF inocula (Glomus intraradices, G. mosseae and G. dussii; components of Vaminoc), on the potato cyst nematode (PCN) Globodera pallida were assessed in a pot experiment in the presence or absence of the nematicide aldicarb (Temik I OG). Mycorrhization of potato roots stimulated an 11% overall mean increase in the hatch of G. pallida within the first 2-4 weeks from planting. In the presence of aldicarb, AMF-inoculated plants exhibited only 57% of the PCN population size (viable eggs (g soil)(-1)) of the non-inoculated plants; in the absence of aldicarb the respective value was 42%. Root length colonisation by AMF was unaffected by the application of aldicarb. Roots of PCN-infested plants exhibited reduced levels of mycorrhizal colonisation (41%) compared to non-PCN-infested plants (45%). The AMF isolates used differed in their ability to produce a plant growth response (expressed as root dry weight, shoot dry weight or total dry biomass) and to affect tuber yield. In this regard, the single Glomus isolates enhanced plant growth (36% increase in total dry biomass) and improved fresh tuber yield by 22% on average, while Vaminoc had, in most cases, no effect. It was concluded that AMF have potential to reduce G. pallida multiplication via a dual mechanism involving stimulation of nematode hatch and inhibition of root invasion. Field experimentation will be required to take this research forward and assess the feasibility of including AMF in G. pallida integrated management strategies.