Can learning about microbial population dynamics help you as a turf manager? In short, we think yes. Let’s start this series with a thread on plant parasitic nematodes (PPNs) by @Deborah_LVS (1/9)

Did you know that it is completely normal for all nematode populations to fluctuate (a lot!) through the year? Eggs hatch, juveniles moult, adults mate, females lay eggs and the cycle repeats. When exactly these events occur, and how many times each year, is important (2/9)

Generally speaking beneficial nematodes, like bacterial feeders, have short life cycles and are highly responsive to changes in temperature & moisture. They are also highly mobile & where populations ‘drop’, recovery & relocation can be quite fast (3/9)

The ‘dip-recovery’ in all nematodes in this study was likely due to progressive drought & simultaneous temperature increase followed by periods of rainfall. Notably PPNs reduced minimally and increased sharply (red line) into June (4/9)

Deceivingly, high PPN numbers don’t always translate into a high stress burden on a plant. It depends on what type of nematode is present in addition to how many. A nematode damage index (NDI) is a measure of risk. In this local study it actually peaked across June & July (5/9)

What did we see in this case mid-summer when NDIs were elevated? Mainly turf thinning, exaggerated in places of uneven moisture distribution (for example close to bunkers where stress is typically high) (6/9)

So what caused the largest broad NDI pattern mid-summer? *Mainly*, though not exclusively, an endoparasite. Meloidogyne spp causes galls to develop & reduces plant productivity! Note how different types of endoparasite can emerge at different times of the year! (7/9)

Other genera of nematode appear at different intervals too, almost in a deliberate staggered way. Note activity is still evident in November despite significant drops in temperature! (8/9)

Key thought: PPN ‘free living stage’ population spikes can be short leaving narrow opportunities to time treatments.

To learn more, or get advice, feel free to contact us (9/9)