‘Tis the Season for . . . (Beneficial) Nematodes
Here’s a question that came in today from Brook Gibson in Seattle, but it could have come in from just about anywhere in the northern tier of the nation this time of year. If you have brown patches of your lawn that pull away from the soil like a bad toupee, read on:
I really enjoy the resources provided on the Safe Lawns website. I am a professional Landscaper for a retirement community in Seattle and writing you because I have been having some issues with my lawn. I have been using Dr. Earth lawn fertilizer (twice now, once in feb. once in May) and still have some major browning areas. I have come to the realization that something may be eating the lawn at its roots and purchased some predatory nematodes.
Are you familiar with this biological control method? And if so, do you have any tips on using the nematodes. My current plan is to mix them in water in my backpack sprayer and spray them on the lawn. I have done some reading and they are not harmful to most “friends of the garden” with the exception of butterfly larvae which seems unlikely to be in the lawn soil.
I blogged about beneficial nematodes back in April when the questions really started in earnest: http://www.safelawns.org/blog/index.php/2010/04/grub-damage-try-beneficial-nematodes/. Many folks had to wait back then because the soil wasn’t yet warm enough. Now, a week or two earlier than usual in the Northeast at least, it is time. Ideal soil temperatures should be above 60 degrees prior to application.
Here is a detailed fact sheet from Washington State University that will tell you more than probably ever wanted to know about the subject: http://cru.cahe.wsu.edu/CEPublications/pnw0544/pnw0544.pdf.