Apr 13, 2011 – A Bite Worse Than The Bark
QUESTION:
What would be considered the best insecticide prevention for bark scorpions? Thanks.
ANSWER:
Arizona is blessed with a few nasty critters, and bark scorpions are one of them. This state has 60 or more different species of scorpions, including the dangerous Centruroides exilicauda, known as the Bark Scorpion for its unusual ability to climb trees very easily. For this reason it can easily enter homes, and is the most common scorpion found inside structures. Adult scorpions over-winter, and the bark scorpions may do so in large aggregations of several dozen individuals. The sting of this scorpion can result in severe pain, difficulty breathing, and even convulsions or death, although since the introduction of antivenin for this scorpion no one in Arizona has been killed by one for the past 20 years at least.
Prevention has to take into consideration more than just pesticides, because these will be relatively short term solutions and would require constant reapplication, especially in the heat of Arizona where active ingredients outdoors would be expected to have a pretty short life. Exclusion to keep them out of structures is so important, and this begins with ensuring that no tree or shrub branches are touching the structure. These can be pruned away to eliminate this common pathway. You also can carefully examine the entire exterior, including up to the roofline since the scorpions may crawl up rough surfaces, and permanently fill in any openings found and ensure all vent screens are in place and in good condition. On the property itself you can eliminate many potential harborage sites for scorpions, and the bark scorpions hide under all the typical places - rocks, boards, and other objects resting on the soil. They also hide under bark on trees, so these can be treated with an insecticide where loose bark is found.
Firewood should be stacked on racks off the soil and kept outside until immediately ready to burn. Garbage cans should be on racks to elevate them. Dense grassy areas need to be mowed and dense groundcovers should be eliminated and shrubs pruned up off the soil. Anything that can be done to expose the soil helps discourage scorpions, as well as the other bugs that the scorpions seek for their food.
Synthetic pyrethroids should still be excellent arachnicides, and wettable powder or microencapsulated formulations might be best. The fast moving scorpion does not spend much time in one place once out and about, so it has a greater chance to pick up particles of pesticide from these formulations as it passes over a treated surface. Products with cypermethrin, cyfluthrin, deltamethrin, and others should be considered. Treatment can be around the base of the foundation, which helps to intercept the scorpions that do make it to the structure, and especially should be made to potential harborage sites. If you can get the active ingredient into the places the scorpions hide they have the highest exposure time and best chance to absorb a dose that will kill them.
What would be considered the best insecticide prevention for bark scorpions? Thanks.
ANSWER:
Arizona is blessed with a few nasty critters, and bark scorpions are one of them. This state has 60 or more different species of scorpions, including the dangerous Centruroides exilicauda, known as the Bark Scorpion for its unusual ability to climb trees very easily. For this reason it can easily enter homes, and is the most common scorpion found inside structures. Adult scorpions over-winter, and the bark scorpions may do so in large aggregations of several dozen individuals. The sting of this scorpion can result in severe pain, difficulty breathing, and even convulsions or death, although since the introduction of antivenin for this scorpion no one in Arizona has been killed by one for the past 20 years at least.
Prevention has to take into consideration more than just pesticides, because these will be relatively short term solutions and would require constant reapplication, especially in the heat of Arizona where active ingredients outdoors would be expected to have a pretty short life. Exclusion to keep them out of structures is so important, and this begins with ensuring that no tree or shrub branches are touching the structure. These can be pruned away to eliminate this common pathway. You also can carefully examine the entire exterior, including up to the roofline since the scorpions may crawl up rough surfaces, and permanently fill in any openings found and ensure all vent screens are in place and in good condition. On the property itself you can eliminate many potential harborage sites for scorpions, and the bark scorpions hide under all the typical places - rocks, boards, and other objects resting on the soil. They also hide under bark on trees, so these can be treated with an insecticide where loose bark is found.
Firewood should be stacked on racks off the soil and kept outside until immediately ready to burn. Garbage cans should be on racks to elevate them. Dense grassy areas need to be mowed and dense groundcovers should be eliminated and shrubs pruned up off the soil. Anything that can be done to expose the soil helps discourage scorpions, as well as the other bugs that the scorpions seek for their food.
Synthetic pyrethroids should still be excellent arachnicides, and wettable powder or microencapsulated formulations might be best. The fast moving scorpion does not spend much time in one place once out and about, so it has a greater chance to pick up particles of pesticide from these formulations as it passes over a treated surface. Products with cypermethrin, cyfluthrin, deltamethrin, and others should be considered. Treatment can be around the base of the foundation, which helps to intercept the scorpions that do make it to the structure, and especially should be made to potential harborage sites. If you can get the active ingredient into the places the scorpions hide they have the highest exposure time and best chance to absorb a dose that will kill them.
