Aug 14, 2011 – Scorpions – Not Just For Pesticides Anymore

QUESTION:

I have a customer who's seeing Scorpions inside the house. What is your recommendation for control overall, and what products would you recommend to use and where?

ANSWER:

The ability to kill any arthropod pest with insecticides relies on a couple of things. You need the bug and the active ingredient (a.i.) to be together long enough for the bug to absorb sufficient a.i. This, for example, is the reason that a crack and crevice application for cockroach control is better than treating baseboards. Since the roach spends 2/3 or more of each day resting in that crevice, it makes sense to put the insecticide in there as well. Now, rather than running quickly across a band of the a.i. and hoping it somehow is picked up by the roach, the insect is sitting on the a.i. for many hours. This also keeps the a.i. away from human exposure and reduces the chances for it to be removed by cleaning or degraded by environmental conditions.

So, back to the scorpions. These are also nocturnal creatures. They are active at night and hide all day under things that provide a darkened, enclosed harborage. I really do believe that on the first visit to a property you should take the time to evaluate that property, identify the likely harborage sites there that could support a scorpion population, and eliminate these as much as possible. Every potential hiding place you can remove permanently will make life that much harder for the scorpions. We can refer back to our triangle of needs that any living organism has, and that is food / water / harborage. The size of a population of pests is dependent on these needs, and eliminating them or reducing them also affects the bugs. You may not eradicate the scorpion problem by habitat modification alone, but in the long run it can sure help. Eliminate dead tree stumps, old logs on the soil, poorly stacked lumber, firewood piled next to the structure, piles of yard debris, etc. Coincidentally, removing all of these scorpion hot spots also reduces harborage for the insects they would prey on, so another attraction is removed.

Some kinds of scorpions - those in the genus Centruroides -  are also excellent climbers, and often use trees to access structures. Unfortunately these scorpions also are the most dangerous ones, and are referred to as Bark Scorpions because of this abiltiy to climb and access structures through openings at the roof line. So, another important step in IPM is to reduce the possible routes of entry by making sure no branches of trees or shrubs are touching the structure, and a pair of pruning shears may be a good tool in the pest management toolbox. In fact, trimming back branches a few feet from the structure will help to keep out an awful lot of other critters too, so it's just good advice.

Making these kinds helps our goal of reducing reliance on pesticides. We must do this if we hope to continue to have the chemical products available in the future. We have a great many organizations and government agencies whose goal is to eliminate pesticides altogether, and showing our professionalism by emphasizing good IPM is what we should strive for. The use of insecticides for scorpions can be highly effective, and synthetic pyrethroids should be good choices. But, these are fast moving and hardy animals, and they could have more of a built-in resistance to a lot of products. We will be most successful if we can put the a.i. directly into the places the scorpions will spend the most time. It seems to me that granular products scattered over the ground would be less likely to give us this contact time. An application of the Talstar G around the perimeter of the structure could be very helpful, as this at least would provide some protection of the structure from scorpions crawling along that area looking for an entry point, but I think it would be better for much of the property to use a liquid application and direct the treatment as much as possible into harborages.

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