When it rains hard, does it kill the fleas that are outside?
If you read our FLEA CONTROL ARTICLE, you’ll learn some key yet often times unknown facts about fleas. One of the big ones is that in general, fleas don’t “hang” out in the open like the grass in a yard. What’s most likely out there would be eggs, larvae and pupae. And this would only be true of larvae and pupae if the conditions are right for them to survive past the “egg” stage. As our article explains, these guys need a lot of water, humidity and food to live past the larval stage. Now if they do survive this stage, they’ll then pupate and when ready to hatch, they’ll only do so when a meal is close by so they can jump on it and feed. The key here is that they’ll only hatch out to an adult when food is close by and not because they’re ready to hatch.
So to answer your question we need to look at the impact rain has on the four stages of the flea’s development. The first stage, eggs, are probably not affected much. If anything, the rain might pick up some and relocate them elsewhere as the water runs down gullies and drains off your property. No doubt some will be relocated to an environment where they won’t stand a chance at survival. But surely some will relocate to ideal conditions so in the end rain can’t directly kill eggs but indirectly it could have a big impact on what happens to any group of eggs.
The next stage, larvae, are small little worm like creatures which are very weak and vulnerable. They need protection from the weather including extreme sun and rain. No doubt flea larvae probably suffer from a hard downpour. In fact, this stage is probably the one that suffers the most from a good rain.
The third stage, the pupae, is much like a flea egg in that it’s protected and secure. Rain, sun and other weather won’t much affect it directly in the short term. And though rain might carry it away to a somewhere more remote destination, flea pupae spend all their time waiting for a meal to come by. Meals can be in the form of a cat, dog, squirrel, chipmunk, raccoon, deer and basically any mammal including people. And they can wait a long time. Upwards to a year or more. All this while you never know they’re out there laying and lurking but if any type of food comes close enough, it will instinctively hatch and jump onto it’s “meal ticket”.
Lastly, the adults are no doubt badly affected by direct rain. It will probably kill most any out in the open but as stated above, adult fleas don’t make a habit of staying out in the open. Remember, adults only want to feed, mate and lay eggs. Most die within a few days of hatching from their pupae casing and for the ones that last 1-2 weeks, they’ll only be able to do so if they’re well protected on some animal’s skin where they’ll be feeding and laying eggs.
So in summary, rain doesn’t really do much “killing” of fleas. In fact, we feel rain really does nothing but make the overall flea problems worse. Having been in the business for over 30 years, I’ve seen a definite pattern between the rain and the fleas. That pattern is simple: more rain, more fleas. In fact, I think it’s safe to say more rain, more bugs! No doubt water is essential for most insects and rainy years are undoubtedly “worse” for most people. Of course for us in the bug business, rain is a good thing :)
Here is a direct link to our Flea Control Article: www.flea.net/flea-control