Crayfish, also known as crawfish, freshwater lobster, mud bugs, freshwater crab, crawdad and several other names depending on where you are in the United States, have become a major nuisance in certain regions of the country. There are over 300 species in our country; several species are raised specifically to be eaten. However, as people have relocated populations close to streams, rivers, ponds and lakes, crayfish problems have developed. This article will explain why crayfish can become a problem and then offer control measures to help reduce damage and populations which are too large.
CRAYFISH BIOLOGY
Crayfish are natural food for many animals including snakes, mink, otter, raccoon, birds and many species of fish. Property owners will plant crayfish in ponds and lakes in an attempt to feed their private fish stock. Given the chance, these initial populations will bloom uncontrollably and if given the chance, can actually reduce fish breeding as well as lead to damage of important lake shore.
HOW CAN CRAYFISH DAMAGE PRIVATE LAND AND WATER?
Crayfish cause damage property several ways. First, they eat a lot. They love fish eggs and fry and seek such food supplies when available. Their tenacious diet will prevent local fish populations from developing properly. Be careful when trying to use crayfish as a main food supply hoping to feed fish which will grow unusually large because of the abundance of crayfish. In the end, a large population of crayfish may lead to decreasing the amount of fish you’re trying to grow.
The second way crayfish cause problems is with their burrowing. This can occur two ways. Initially, most species will burrow out onto the water shore and emerge a few feet up on dry land. Their burrows serve as a way they can retreat from the water as well as to provide shelter. This happens all the time where crayfish are present; most of this is never noticed by land owners.
However, as populations of crayfish increase, their burrowing will reach further and further out into turf areas. Overcrowding will cause them to leave the water to nest. Basically they’ll be walking out past existing burrows to dig new ones further and further away from water. This digging will occur mostly at night and generally leads to turf damage in two ways.
Crayfish burrows will be killing plants and shrubs as they dig. Additionally, their burrows are unsightly. Some people refer to them as “chimneys” or “crayfish castles”. Regardless these “castles” are not attractive in the yard.
Another type of damage which stems from these burrows is caused from predatory animals which will dig looking for food. Raccoon, skunk and armadillo will regularly dig into turf causing even more of a mess as well as additional damage. Remember, humans are not the only animal which enjoy a good crayfish meal.
In summary, crayfish can rapidly multiply leading to populations which the local water environment may not be able to sustain. To keep these numbers in check, there are two things you can do.
NET TRAP CRAYFISH
If you have a lot of water on your property and need to remove a lot of crayfish rapidly, use some CRAYFISH NET TRAPS. These are relatively inexpensive and very effective at catching a lot of crayfish quickly. Set them out along shore lines with twine leads for quick removal. Feeding crayfish are easy to catch and will readily come onto these offerings. But in heavily populated waterways, you only have to set the trap in the water and within hours these nets could have several on top ready to be removed.
CRAYFISH DETERRENT
If you don’t want to kill the crayfish or if you only have a few areas with activity, apply one of our repellents.
PEST XEMPT GRANULES release a super strong and persistent wintergreen like odor they don’t like. Place 1-2 oz per “castle” and you’ll see instant results. Once applied, they’ll leave within a few days.
It won’t hurt them or any other animal or insect. But crayfish won’t like its “taste” once it trickles down into their home and they’ll move away.
Xempt G is packed 4 bags to a box; each baggie is 8 oz and can treat 4-8 nests.
If you prefer to spray, PEST AWAY SPRAY is a proven deterrent when applied to targeted castles. It’s concentrated, completely organic and when mixed with water, treated castles will be abandoned and crayfish will retreat back toward their main water supply.
Pest Away is made with all natural organic essential oils and gets mixed with water. It won’t harm wildlife, insects, birds, pets, etc. but due to it being so concentrated, it makes crayfish “uncomfortable” so they leave.
Our 8 oz jar mixes 2 oz per gallon of water and you should plan on spraying each castle with 16-32 oz of mixed material.
Now keep in mind these are repellents so there is a chance they may relocate to another area in the yard. And if this starts to happen, you should consider treating more of the yard with both the granules and the spray. The best approach is to chase the ones closest to the home first taking back 2500-5000 sq/ft at a time. Once this area is secured and they’ve moved on, you can make placements further “out” away from structures to cover more of the yard and reclaim more property from them.
CRAYFISH SOUND REPELLER
After you apply granules/spray, consider installing our SOLAR POWERED SOUND REPELLER for a more permanent solution. This design is one of kind and not available elsewhere. True, there are models which look like ours but they don’t have all the features our units have which are important for certain pests like crayfish.
This device uses the sun to charge an on board battery so it runs on its own power around the clock.
Once installed and powered on, it will release different sounds including rattles and vibrations that will both move the ground and create a sound wave crayfish don’t like. By default, they vibrate several times a minute and they change their cycle.
In addition to sound, they use small white LED bulbs located on underside of controller head. These light up when its dark which effectively tell you the units are working. When placed close to active crayfish, they will become uncomfortable.
Coverage for these units when used on crayfish can be as much as 5,000 sq/ft per unit. But not initially.
So when you first place them out, you’ll want to start at the area “closest” to you, basically their “latest” nest/castle locations. We call it the “outer edge”.
This “outer most” area should be lined with repellers spaced 30 feet apart. After a week, move them toward the retreating crayfish which will probably be further “away”. Do this every week, moving them about 10 feet further “into” the crayfish areas so you are effectively “taking back” some of the yard/land.
To insure they don’t “flank” your placements, leave at least one behind to cover the vast open “clean” area. For that placement, the 4000 sq/ft will be a good amount of land that can be protected per machine.
For the front line, place units 30 feet apart making the “line” as wide as is needed. So if you have a 60 feet line you want to create, there will be 3 units needed. For a 90 foot line, 4 units.
Ultimately, once the land is purged of activity, place the units out in a “checkerboard” pattern so the entire yard is protected.
Installing Ground Sound Repellers should be done after you treat active burrows with either Pest Rid,. Sulfur or Giant Destroyers. Plan on getting them charged for two days before installing them to ensure their battery is fully charged.
DO NOT force these into the ground; use a good SOIL AUGER to drill the proper sized holes.
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Anonymous says
Thanks for the info. My yard has been taken over by these creatures. Having always lived in the desert areas, this is a new problem for me.
gary says
Can you tell me where to buy these repellent granules?
Tech Support says
I’m sorry but we don’t have any distributors at this time. But you can get them from us direct:
https://bugspray.com/exempt/granule/pest-xempt-granules-2-lb
Ann says
Thank you so for this information. We’ve always had a few mounds but over the past three years but now they’re taking over. We also have a lot of snakes. I never thought about the crawdads being a food source for the snakes. Your site has been very helpful and we will be ordering your products. Thank you.
Joy says
I have several mounds in my yard. I also have a dog that continues to eat them. Are they harmful to dogs? Can they cause Gallbladder issues?
Tech Support says
Joy,
We’re not aware of crayfish causing gallbladder issues in dogs but like people, pets can be allergic to the crayfish shell.
In general, Vets will say to be careful giving dogs shrimp, crab, lobster or crayfish because of the spices we add to them when we cook. But these same vets will also say to never give pets the shell as this can be more problematic for other reasons, mostly allergies, similar to what people experience.
At this time you should consider treating them as explained above.
Another option is to install some of our ground sound repellers. We have units afield being tested right now that are performing well on crayfish so we’re optimistic they will do the job. Basically they get installed along the side of the yard where they crayfish are active and the sound they send out combined with the vibration waves they transmit to the ground is highly repellent to crayfish making them leave. If the data continues to support using them, we’ll be adding these devices above as a viable way to get rid of crayfish. We know they work on snakes, moles, gophers, voles, lizards and frogs. And they pose no hazard to pets. Also, they are solar powered so once installed, they’ll work around the clock needing no maintenance which is nice.
Solar Mole Repeller: https://bugspray.com/repellents/sound/deluxe-solar-powered-mole-vole-gopher-snake-repeller
Technical Support
U-Spray Bugspray
http://www.bugspray.com
1-800-877-7290
Tech Support says
UPDATE ON THE GROUND STAKE REPELLERS FOR CRAWDADS:
After several customers started using our repellers to chase away unwanted crawfish, we can safely report they are doing the job. Basically in yards where they’ve been deployed, everyone has found the crawfish move away and abandon their homes. It’s now been 3-4 years of success using them to chase off crawfish along with snakes, moles and voles.
Mary P says
We have 8.5 acres which is all bordered by a creek. The pastures are riddled with crayfish burrows, one in particular. What would be the best option for getting rid of crayfish in an area this large? The burrows created spreading holes which the horses can step in and get injured. We have horses, goats, dogs, cats, and chickens.
Thanks!
Tech Support says
Mary,
As detailed in our article above, using the Xempt Granules are usually the most effective way to get them to move away. This will force them out and if you’re renewing the treatment every 60 days, it could prove to be long lasting too.
But if you want to make sure they don’t return, install the sound repellers listed above. They’ve proven super effective now that we have a running history of them being afield and results we can chart.
Now you will need to do this in “sections” starting from the furthest part of the activity away from the creek and then pushing them back to where they came from. Do this by clearing them out in 2500-5000 sq/ft areas at one time. The goal is to make them retreat by using a “line” of repellers and granules.
Now once you go 2 weeks without them coming back along that line, you can take back more land by applying more granules and relocating the repellers even closer to the creek. Eventually you should be able to push them back to where you won’t have them active in the land you want to keep clear.
Once areas are clear, leaving the repellers in place will keep the area clear. And they should be able to protect 1/8 to 1/4 acre per unit once the land is purged but again, the exact max protection you get will depend largely on the type of ground so its hard to say for now. But in general, the more “moist” it is, the less powerful the sounds and rattles will be leading to less coverage per unit.
In summary, the crayfish took time to invade and disperse over the area so plan on taking some time to clear them out. But over time, you should be able to reclaim most all of the “lost” land.
Technical Support
U-Spray Bugspray
http://www.bugspray.com
1-800-877-7290
PS: Are you signed up for our informative twice a month Pest Report Newsletter? More info here: https://bugspray.com/bugspray-pest-report
Donna says
When applying a granules or spray, should all the water in your yard be gone or can it be applied when the ground is still wet and\or waterlogged?
Tech Support says
Donna,
Water is a carrier for most everything used for this pest so it’s okay if the area is damp. Basically the wetness will help the treatment get faster and deeper penetration.
Now if the castles are flooded with levels of water that are not draining? Wait. Once the treatment gets to sit in the hole/castle for 1-2 days, the odor and bad tastes will continue to linger even if it floods again so you don’t have to worry about loosing the treatment if it gets too wet. By design the released actives will tend to lock into the soil where applied IF its not flooded when you make your initial application and it gets to dry for at least one day.
Technical Support
800-877-7290
Dee Vida says
I wonder about the sound repellers sticking up in the yard- do I have to remove them every week when I mow, or do they sit flat on the ground? Can I mow over them?
Tech Support says
Dee,
So for sure the units will be “sticking up” as you can read about on our product page here:
Solar Mole Repeller: https://bugspray.com/repellents/sound/deluxe-solar-powered-mole-vole-gopher-snake-repeller
But when using them for crayfish, the process will involve installing them first in the grass but then moving them out further and further “out” eventually having them at the lawn’s edge. This way they will not be “in” the grassy areas you’re cutting unless you need to keep them there. But we don’t recommend doing that; no need to for most problems.
Technical Support
bugspray.com