THE CRANE FLIES ARE COMING, THE CRANE FLIES ARE COMING!!
Actually, the adult crane flies are here. I feel like I’m beating the proverbial dead horse about the most destructive turf insect we have in the Portland, Oregon, Vancouver, Washington and Clark County area in general, but it’s that time of year once again and this is important.
The European crane fly (see photo of adult above) is our most common, and potentially devastating turf pest. As you can see, the adults resemble an oversized mosquito. We are observing the adults mating and laying eggs right now, in disturbingly high numbers, all over our area.
Interestingly, the adults do not cause any direct turf damage themselves. That dubious distinction is reserved for their larvae (see above photo). When the cane fly eggs hatch, the larvae feed on the roots of desirable grass plants, and in many instances, cause severe turf damage. Ironically, these little buggers basically ignore the undesirable grasses that invade most of our Pacific Northwest lawns such as barnyard grass, crab grass, goose grass and poa trivialis. I have personally seen lawns literally defoliated of all the good rye grasses and fescues, leaving only the “cruddy” grasses in clumps. It ain’t pretty!
So, what do you look for to avoid being a crane fly larvae “victim”? First, keep an eye out for those adults. You can see them around your house on the siding, especially around exterior lights, in spider webs and around eves. They will often cling to shrubs and hedges during the day, avoiding direct sun on hotter days. You may notice them flying around your lawn as you disturb them while mowing. They can also be observed mating in the lawn and, after mating, the females can be seen actually laying their eggs (their ovipositor or “rear end”) thrust into the turf.
If you are seeing lots of adults, chances are good you will need to apply the proper insecticide to control the larvae AFTER they hatch. Timing is critical to good control as most insecticides have relative short residual activity. Go after them too early and the insecticide will not be effective. Go after them too late and your lawn can suffer significant or severe damage. Depending on weather conditions, location and field observations, Tuff Turf usually starts initial control applications in late November, with a second application approximately six weeks later to catch any secondary or late hatchings.
Crane fly larvae are generally found in moist, more shaded turf areas, but not exclusively. Initial symptoms of damage may appear as purplish discoloration of grass, followed by distinctive thinning of the turf. The presence of large numbers of birds, especially starlings, feeding in your lawn is also symptomatic of cane fly larvae infestation. You can check by going to the edge of a suspected area of damage and digging into the soil one to two inches and looking for the actual larvae.
The bottom line is: if you want to protect your lawn, be aware of this pest. I have seen more turf damage done by crane fly larvae during my twenty-two plus year career with Tuff Turf than all the other turf pests combined. If you have questions or need help, we are just a phone call or email away.