I bought three different species of nematodes from an online vendor: Heterorhabditis bacteriaphora, Steinernema carpocapsae and Steinernema feltiae (250 million each). I've sprayed the H. bacteriaphora by filling a 4-gallon pump sprayer similar to this one by filling it half full with water, added half the bag of nematodes, agitating slightly, then filling with water. Once the sprayer was empty I repeated the process for the other half of the bag. The time of day I did this was late in the evening since they apparently are killed by UV, it was a pretty cloudy day and the ground was still wet from rain the day before.

Before I repeat this for the other two species which are currently living in my fridge I was hoping to verify that what I did worked. The vendor says to use them no more than 14 days after receipt though, so the clock is ticking. How can I tell if the nematodes I sprayed are alive, given that I do not have access to a microscope? Is it possible to see any sort of evidence of activity less than 14 days after application?

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Overnight temperature is currently ~45-55°F. My intention is to control pests, namely fire ants, fleas, aphids, grubs, etc. For everything except the ants and fleas though the measure is preventative. I sprayed a large area of mostly lawn grass, as well as rows where I plan on planting blueberry bushes, but I sprayed directly on the ground. I also read somewhere that some of the associated bacteria related to these parasites is beneficial for the soil which seemed like a "good" thing, but whether that's true or not I am not sure.

  • Can you clarify a few things please - what problems were you trying to treat with the nematodes, and what plants are they? Are the plants in the ground outdoors or in pots? When you say you sprayed, do you mean a foliar spray or applied to the ground? What are your outdoor temperatures currently (especially overnight)?
    – Bamboo
    Mar 29, 2020 at 11:56


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