Friday, August 22, 2014

Argentine Ants

I've been getting samples submitted where people suspect that they have Tawny crazy ants infesting their property.  They report light brown ants in dense populations getting into everything.  Once the samples are submitted, I discover that they are Argentine ants.  So why are people mistaking Argentines for Tawnies?  Well to the inexperienced they can look very similar especially when you don't have a good hand lens or microscope to look for hairs on the body.  Also, both of them can have high population numbers and supercolonies.

Argentine ants are light brown to brown in color and all workers are the same size (about 1/8").  The legs are not overly long like with crazy ants, but this can be difficult to determine unless you tend to look at ants a lot.  If you have a hand lens, you can check out the tip of the abdomen first.  Argentine ants do not have a sting and they don't have a circle of hairs at the tip of the abdomen.  Next, look at the thorax of the ant.  If the thorax does not have hairs, then it's most likely going to be an Argentine ant (Crazy ants have long paired hairs on the thorax). 

Argentine ants in the Urban Lab at TAMU.

The other ant that breaks out in the same couplet  (in a dichotomous key, characteristics are paired so that you work your way through the key by choosing one of the couplets that has similar characters to your specimen and the paired characters that you choose from is a couplet) as Argentine ants are the Cheese ants.  If you have multiple ants, then determination of cheese ants is very simple....smash one of the ants and smell your finger.  You're thinking I'm crazy now...right?  I'm not (my mother had me tested...actually that was Sheldon, not me.  If my mom had me tested she did not tell me the results which could be good or bad).  Anyway, I digress.....have you smelled your finger yet?  If you have cheese ants then your finger will smell like blue cheese.  I swear! 

So, if you have small to medium brown ants trailing around that worry you, you should:
1. Squish some and smell your finger.  If you have a blue cheese smell, then you have Cheese ants.
2.  Look at the thorax with a good hand lens or microscope.  If you have paired hairs on the thorax, then you have Crazy ants.  If there are no hairs then you have Argentine ants.

So here is my disclaimer.  This method is really simplified and I may possibly get lynched by entomologists and even more so by myrmecologists (ant specialists) for simplifying it so much.  Ant identification involves looking at nodes, counting antennal segments, looking at hairs on specific parts of the body amongst other things, so this is a generalization but may help you out.  It is very important to identify the ant that you are trying to manage before you try to control them.  If you cannot do this or are unsure of your identification, then send it to me and I am happy to look at it for you.

All Bugs Good and Bad Webinar Information

The webinar from August is now posted for you to watch at your convenience.  It is "Minimize Mosquito Problems" by Molly Keck.  You can find that here (click watch recording in the top right corner):
The next webinar will be held on September 5, 2014 at 1PM CDT.  That webinar will be "Kudzu Bug Takes Over the Southeastern U.S./ Brown Marmorated Stink Bug--All Bad" and will be given by Dr. Michael Towes and Dr. Tracy Leskey.  You can find more information and a way to link to the webinar here:

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Friday, August 8, 2014

Asp caterpillars

I've been hearing reports of people being stung by asps (puss caterpillars).  The larva is the problematic stage for this insect as the caterpillars often fall out of trees and land on unsuspecting people below.  When this happens, the person may get stung.

Image from
The caterpillar has venomous spines which can cause a varying reaction.  There are some people who react more severely to the toxin than others.  The severity of the sting can also depend upon the thickness of the skin where the sting occurs.  Often stings will cause localized burning and redness (usually in the shape of the caterpillar) sometimes paired with swelling.  More severe reactions may cause fever, headache, nausea, vomiting and other symptoms.  If you are stung by a caterpillar and are concerned with your symptoms, seek medical attention.

Smaller instars are yellow in color while later instars turn pale green to white.  The spines containing venom are concealed in later instars by long, soft-looking setae (hairs).

Asps are know to feed on foliage of over 40 genera of plants.  They will often wander to nearby plants when the are preparing to pupate.

If you have large populations of these caterpillars and would like to manage them, you can try Bacillus thuringiensis var. kurstaki (this targets caterpillars only, but will also kill "good" caterpillars).  You may also look for active ingredients such as spinosad or azadirachtin (both naturally-derived products).  These products tend to work best on smaller instars.  Another option would be a residual pesticide labeled for caterpillars that is okay to use on plants.