Landscape - Insects and Swimming Pools

Clients may complain to you about insects in swimming pools. The following is some information that you can pass on to them.

Swimming pools attract a variety of insects. Honey bees come to collect water for use in their colonies. A few aquatic insects, mostly bugs and beetles, come because water is their natural environment; to them, a swimming pool is just another pond. A few (like thrips) come as a result of disturbances – cutting hay fields or wheat. Finally, there are those that just accidentally fall into the water and cannot escape.

Honey bees need lots of water to maintain optimum hive temperature and humidity; a nearby swimming pool may be the most convenient supply, causing alarm to pool owners and users. Worker bees that find a good water source will recruit colony mates to join them. Over time, hundreds of bees may be appear. Some will fall into the water and drown but others will keep coming. They are preoccupied with this task and generally are not a threat. Dealing with bee visits to small kiddy pools can be as simple as moving the pool to a different spot in the yard every few days. Bees follow directions very strictly and if the pool is not where it should be, they will not find it easily. You can stay ahead of them with the moves.

Aquatic insects, such as backswimmer bugs and toe biters, may arrive in large numbers as they fly from ponds in which they developed to colonize other bodies of standing water. In some cases, they may be abundant enough to clog filtering systems. Usually, this mass movement lasts only a few days. Backswimmers are predators; they can give a painful bite with their piercing-sucking mouthparts. There should be no question as to what the toe biter can do. The pain from these bites is similar to a bee sting but there is no toxin.

Thrips can make a dramatic appearance. These tiny elongate yellow insects were described on one insect ID form as follows: "These little biting things covered an aboveground pool and deck. They were so thick that you could wipe them off with your hand. They have painful bites, children could not play in the pool for them." Thrips show up at pools probably drawn to water or driven there from nearby recently-cut hay fields. On normal days thrips use their abrasive mouthparts to rasp at plant tissue, especially flowers. However, they will scrape skin, perhaps as they attempt to pick up small amounts of moisture. An occasional thrips scrape probably is tolerable but lots of them do not add to the swimming experience. A strong jet of water may be used to plaster them to decks and other surfaces where they have accumulated.

Finding and managing the source of an insect problem usually is the most effective management practice but this is rarely possible or practical with swimming pool invaders. There is no safe or effective means of treating pool water to keep intentional or accidental invaders away. Covering the pool when it is not in use may be the best and only way to exclude chronic problems with unwanted creatures. Fortunately, this may be needed for only a few days at a time. The clumsy pool invaders are the easiest to handle – the few that fall in can be removed with a cleaning net or cup.

Reprinted from "Few Management Alternatives for Insects around Swimming Pools" By Lee Townsend in the current edition of the Kentucky Pest News http://www.uky.edu/Ag/kpn/kpn_09/pn_090707.html