Stratiolaelaps scimitus

Beneficial bugs
Biological Controls, Photo © Jenn Nash, 2014

by Jennifer Nash

Every farmer or gardener knows, once in a blue moon you are besieged by pests. In 2013 we had our first experience with poultry mites. They’re tiny and move quickly. Mature mites are up to 1 mm in size, so are visible with the naked eye. In 37 years of raising poultry we’ve never had them. Did they come in on the wild finches that sneak into our coop? Did we miss them during quarantine on the new chickens we bought that year? Who knows, but we got them.

Poultry mites drink chicken blood; almost doubling their size when full. Think leeches! Chickens become anemic, and can even die from an infestation. Sitting hens are at greater risk of a slow blood-letting death. In their determination to hatch chicks, hens don’t leave the nest, where the mites congregate and breed in the added warmth.

Our first line of defence was to rip out all the wooden nesting boxes my father built in 1978 and burn them. Two rows of Rubbermaid tubs that I can easily monitor and semi–sanitize weekly were installed. Next, we scrubbed down the roosts and sealed them with thick white paint. We use the deep litter method in our coop, so we took that back to below ground level and replaced it with inches upon inches of fresh shavings. Finally, we dusted all the birds with diatomaceous earth using Joel’s ingenious method of filling a nylon knee–high like a powder puff; and applied VetRX to everybody’s beak, comb and legs. Phew, everything under control.

I monitored the birds for the remainder of the year with no visible signs of the mites returning. Assuming the bitter cold weather we’d been having that year would keep any orphans in check, I relaxed. Just before Christmas, one of thirteen feral October hatch chicks was looking a wee bit frumpy. Argh! The mites are back. How can that be at minus 20 degrees? I gather the chickens themselves had been keeping the mites warm. I’m losing sleep again, and “those poor hens”. In the presence of even one vampiric mite, my skin begins to ‘crawl’.

Joel suggested I contact Stacey Hickman – our entomologist at Natural Insect Control (NIC) – to see if she has a biological solution. We’ve purchased biological controls for the greenhouses from NIC for years. I procrastinated for a few days thinking I knew there couldn’t possibly be a good bug that would eradicate a bad bug, in this case. I emailed Stacey. She did a little research, and low and behold, one of the predator mites we already use for fungus gnats in the greenhouses is also a natural predator for poultry mites. In fact, Stratiolaelaps scimitus (good mite) feed preferably, and are a natural enemy of Dermanyssus gallinae (red poultry mite). The predator is safe for the birds, is endemic (meaning it’s not a new species into our environment), they adjust to the coop climate, and they are self–limiting. When the primary food source (the poultry mite) is quashed, the predator mite will starve and die.

As soon as the weather warms up to around 20 degrees we release a few bottles of “Stratios” into the shavings of the coop. I’m elated that we now have a biological weapon. We don’t have to resort to harsh chemicals, forcing us to dump perfectly good eggs for weeks following treatment. Happy hens and happy Jenn!