Anasa tristis

By starlight1153 (starlight1153) on February 17, 2014

Anasa tristis is a pretty sounding scientific name don't you think? Kind of rolls off the tongue and makes you think of a fantasy place. However, its common name is enough to have gardeners upset and going into panic mode when they hear the common name spoken. So I am going to whisper that the common name is "squash bug.

Anasa tristis is the scientific name of this major pest to gardeners around the country. It's Order is Hemiptera and it is a leaf-footed bug from the Family Coreidae.

Squash bugs are a major pest of home gardeners as well as commercial growers. Their main diet is such vegetables as squash, pumpkins, cucumbers and melons, but other crops in the curcurbit family can be tasty morsels too.

Squash bugs are what is known as a "true bug" because they have piercing-sucking mouthparts. That means they have a mouthpart that sort of resembles a needle.   This needle-like body part is called a stylet. The way it works is the squash bug finds plant foliage or plant fruits to forge on.   Once this is accomplished the squash bug uses this sharp stylet to pierce through the flesh of the plant where it starts to suck up the sap.    As more and more of the sap is drained you will see the plants beginning to wilt. Eventually, if enough of the sap is drained, the plant will die. Upon seeing wilted plants, most gardeners have a tendency to think the plant has just wilted from lack of rain or too high of humidity in the hot afternoon sun. The only way to be sure if you have a nutrient, water problem or a squash bug pest problem is by scouting your plants.

Come spring as the temperatures start warming and you have your newly planted seedlings in the ground or your seeds have sprouted, the squash bugs that have over-wintered emerge too. They have two goals in mind.   First is to immediately start feeding and the second is to find mates and start laying eggs.

The squash bug starts out as an egg that is white but then gradually turns to a yellowish-brown color eventually turning a orangish color when the egg fully dries. The eggs are very small, barely a 1/16." They are usually bullet shaped and are laid in clusters of 30 to 50 eggs which makes spotting them a bit easier. The best place to constantly look is on the underside of the leaves.   Adults usually lay the eggs near the edge of the underside of the leaves.   More than one adult can and will lay eggs on the same leaf, so it is good to check the leaves thoroughly.

Once the egg matures and hatches, the newly emerged nymphs will start to feed as ferociously as the adults did within one to two weeks. The newly hatched nymphs are very small in size. They can range from 3/16" to 1/2."   When they first emerge their color can range from a whitish to a green-gray. Materials from the inside of the egg that still surround new hatchlings may even make the nymphs look like they are covered in a powder, but they will eventually turn the dark brown color of the adults.

As time goes by, usually within 4-6 weeks and after several molting phases the nymphs will look just like the adults and besides being eating machines, they will become new egg laying machines.

Besides hand scouting the underside of all your leaves, another way you may be able to tell you have a squash bug problem is by the color turning of your leaves. Your nice healthy looking green leaves will start showing spots of light green and eventually yellow where the sap has been drained.   Eventually those spots will turn from yellow to brown.   Heavy feeding on the plant will cause it to wilt. This is because the squash bug sucking the sap from the stems causes a lack of nutrients and water that the plant needs to grow and survive.

Small seedling plants will usually die fairly quickly from the feedings while larger plants may struggle and lack the ability to produce runners or fruit. Once fruit starts appearing the squash bugs will also start to feed on them.

Once you have them, squash bugs are not easy to remove. They are fast footed, great at hiding and disappearing before you can remove them.    Pesticides are not going to work so save your money. The plants in the curcurbit family have so many vining and jointed parts besides foliage that a pesticide usage is just not feasible.   Using a pesticide in the long run only makes for the possibility of you poisoning yourself, plus any other beneficials you may have in your garden.

It is best to use organic best cultural practices to remove them or at least get them down to a manageable level.

In the spring, as soon as you are able to get out and work in your garden, start removing any debri that is hanging around.   That is one of the main place that is a favorite over-wintering spot for this pest.   Also, those of you that grow perennials or small, low growing shrubs, check around the base of those plants too. The bugs will migrate and hide there until spring and they can emerge.   The squash bugs generally start emerging in mid to late spring and on into the early summer from winter hibernation. Most folks are so busy planting at this time that they just don't realize that these bugs are hanging out, hiding on the sidelines, hoping you won't find them until your newly crop of seedlings is ready for them to feed on.

The best way to get rid of and or control is to scout everyday.   It is a pain for sure, but you can go out one day, remove lots of clusters of eggs only to go out the next day and check those same leaves to find they loaded up again with eggs.   One week after you have put seedlings into the ground or your sown seed is showing at least the first 2 sets of true leaves, start scouting for eggs.

The eggs can easily be removed by taking your fingers and squishing them.   I squish and gently try and pull the now destroyed egg masses to edge of the leaf and off.   It does get messy if you have a lot of egg clusters, so I would recommend carrying some water along to wash your fingers with. Be very gentle when removing the egg masses. They do stick to the leaves tightly. Gently try and get behind the egg clusters and scrape them forward on to your fingers than squish.    Now if your a squeamish type of person, and I was too at first, you can get a rubber spatula and gently scrape the eggs into a container and than destroy them. Best to use a little bit of bleach water as plain water or even soapy water will not kill them.

It's hard to capture and destroy the adults. They are not called leaf-footed for nothing, although I think they should have been named fast-footed instead. Trying to catch them by hand is very hard and very frustrating and while you spend your time chasing them round and round the leaves and stems you are probably going to do damage to your plants or create new wounds which can cause a host of other new problems.

Instead, lay pieces of wood, it doesn't have to be thick pieces, or even some heavy cardboard down. If you do use wood, using pieces that are at least 1" thick and 10" or 12 " wide will allow you to walk on the wood with no problem.   Place it as close to the base of the plants as you can without causing damage to the stems. The squash bugs will take refuge under the boards and the cardboard.   Now comes the fun part and this is a process that can be used for many of your garden pests instead of using chemicals.

One process is when you lift the boards or the cardboard up, have a hammer or a tool like it in your hand and be prepared to act fast. You can use the hammer to stun them or kill them. It works well, but like I say, you have to move fast. Watch you don't hammer your fingers or toes while you chasing the bugs.   Don't worry about ones that may escape back onto the plant foliage, we'll take care of them in a minute.   The ones you have killed, take and remove the dead bodies from the garden area.    If you don't the smell from off the bugs will alert the other bugs to stay away from that trap area you have prepared.    You also might want to wear a mask while your doing this too.   Squash bugs will secret and odor when they are disturbed on the plant. When you destroy them you really get a good whiff of not so nice a smell.

Now the second and best way to remove these pests and any pest that has legs and can crawl is believe it or not a car vacuum or a dust buster. Just make sure it is one that runs on batteries.   Seems like you always run out of extension cord when you need it to get the far reaches of the garden.   Those small vacuums are powerful enough to suck up the bugs.   Yes, the initial investment may be a little expensive, but it is a tool that you can use over and over for many years and in the long run will save you many dollars over having to buy non-working chemicals and pesticides.

Once you have the bugs in your vacuum container, take it to a place away from your plants and dump it into a bigger container of bleach water to finish eliminating them. Just make sure your container is deep enough so that they don't have time to crawl back out before you get them in the bleach water or hand destroy by squishing them.

Now before you eliminate all of them, try and get over your fear and squeamishness and take a close look at the belly or abdomen of the bugs. If you see little clusters of eggs attached on the belly, take that bug and put it back in your garden somewhere, but not on the plants.   Squash bugs always lay their eggs on the leaves or the stems of a plant. They do not keep eggs attached to themselves, but what does is a benefical insect called the Trachinid Fly , Trichopda pennipes. The Trachinid Fly is a parasitic fly that is not only beneficial to help control the squash bug population organically, but also many other garden pests.

Chemical control are almost useless and the only thing by using them you will do in the end is possibly poisoning yourself, friends, children who may pick and eat the fruit from your garden and destroy any beneficals in your garden. When you use chemicals you also deplete the natural honeybee and other pollinators that are necessary for fruit and seed production in your garden.

Which also brings up this point I would like to make. That is the knowing of your insect eggs.   In the insect world so many bugs look the same and even more so does their eggs. There are lots of good insect and bug spots on the web. If you look you will see for example pictures of the squash bug eggs and the benefical Lady bug beetle eggs, which look closely alike. Check them out, copy and paste the pictures together on a document along with other bug egg and nymph stages. Than print the document out and copy and paste it into a small notebook that you can carry around the garden with you. That way you can better identify the correct eggs you want to destroy leaving your beneficial eggs to grow. Using those small 3" x 5" or 4" x 6 " index cards that are wired together with easy flipping of pages works great.   So I don't have to keep replacing pictures, I will seal them in a plastic cover and than glue to the notebook pages.

In closing, again I say the best thing you can do for yourself and for your plants is to keep the garden areas weed and debris free. This will remove potential shelters for pests and ensure a healthier environment for your plants growth. Scout everyday.   You'll be amazed at some of the other things you can discover about your plants and soil by scouting for pests.

If you use good gardening practices, the pests will be gone, the plants healthy, the fruit produced in abundance, so that all you have to do is worry about finding the perfect squash casserole recipe or one for pickling cucumbers.

Special Thanks to Joseph of Lofthouse Gardens for use of his squash photograph http://garden.lofthouse.com

Want to learn more about good bugs and bad bugs?   Have a pest you want to get rid of? Want to learn what you can do to attract more beneficial bugs? Than visit the Good Bugs... Bad Bugs Forum in EG

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Comments and discussion:

Subject Thread Starter Last Reply Replies

Yucky squash bugs! wildflowers Feb 22, 2014 5:06 PM 2

You really got me with the intro. Zanymuse Feb 19, 2014 6:36 AM 1