Wednesday, June 20, 2012

Genista Caterpillars (Uresiphita reversalis) Pest to Texas Mountain Laurel


This morning I took 30 of these buggers off one little Texas Mountain Laurel tree--all the tree's new growth had been skeletonized before I saw them.  These caterpillars become a brown night-flying moth. Judging by my yard, the moths are prolific reproducers.

To find out if your trees are infested, look for loose webbing on new leaves, or leaves eaten into a skeleton.  

It doesn't take long for a clutch of cats to chew through a flush of leaves; and losing the new leaves slows growth. 

Birds don't eat genista caterpillars because of the alkaloids absorbed from the plants. The only natural enemies I've seen (besides my fingers) have been fire ants and assassin bugs, but your tree may have a tough time with a combo of genista, summer heat and drought while you wait for assassin rescue.

According to Texas A&M's website, "Plant health is generally unaffected by feeding unless large numbers of caterpillars cause heavy defoliation (leaf loss)."  The site advises using manual control otherwise.

If you find webbing, brush it off and take the caterpillars off by hand-picking or blasting with a stream of water.

It's easiest to find the caterpillars in early morning while they're still in the webbing.  They look hairy but don't sting.  If you're finicky, wear gloves.

And think of the purple flowers you'll have next spring.

Copyright 2009-2013 Kathleen Scott, for Hill Country Mysteries. Unauthorized reproduction is prohibited.

16 comments :

Jayne said...

Is that their only host plant, or are they not picky? I'm sure I've seen them here, but I don't have Texas Mountain Laurel.

Steph@RamblingWren said...

Oh, I can SO relate to your caterpillar problem. They have stripped our beautiful Mountain Laurel tree. They look very similar to "tent caterpillars". I don't mind feeding the caterpillars that turn into butterflies, but I guess all caterpillars got to eat:)

LindaCTG said...

Hi, Kathleen! Indeed, we featured this on CTG recently since they can defoliate a tree while you make coffee. But thank you for this additional insightful info! And I also thank you for this because our genistas have come and gone for now (though I'll go check mine right this minute, in this totally bizarre year). Interesting to know that you're being invaded now; ours our usually earlier. I'll make a note of it. Thank you!

Andrea said...

Oh that's scary for me, i can't still touch them even with gloves! Grrr! We have lots of moth larvae too, which are even more scary than those, bigger, longer and more hairs. And they settle together in big patches on trunks of trees at daytime and devour all leaves at night. The ground below becomes a yucky area in the morning after they excrete all their eaten leaves. Moths are really more devastating than butterflies.

TexasDeb said...

Our trees were attacked this year as well. We tried a non-ionizing surfactant plus the mildest spray we could find on our laurels - we were concerned the caterpillars would kill the tree, they got set up so quickly and ate so much. Most of them were way too high for us to reach though I admit - once I got a good close-up look I was glad not to have to try to pick them all off. Ugh plus.

shrink on the couch said...

Such small creatures who do such big damage!

I think of your blog post anytime my newly hung feeder successfully entices a hummingbird. Or two. Proud of myself for consistently maintaining it (cleaned out mold from the little "flower" centers, even).

Pit said...

Hi Kathleen,
We have/had them, too. On our recently planted Mountain Laaurel I luckily discovered them early enough to save the plant. I must admit, though, that I didn't pluck them off but used and insecticide. There are some on our older tree, too, but luckily only a very few and they seem to have died - or developed - and they have not eaten away too mnay of the leaves. This tree, btw, would be too big for me to reach up all the way to pluck them off or spray them. Thus I'm happy they weren't out there in numbers.
Best regards - at present from lovely Fredericksburg, lokking for a place to relocate to,
Pit
P.S.: We've found our future dream home! :)

Vicki B said...

I noticed a new infestation this morning. I have 5 smalll trees in my backyard here in the Plum Creek subdivision in Kyle. Just sprayed with Thuricide today. Will go out and check for survivors now before they have a chance to spin any more webs of destuction overnight. I really dislike these creatures intensely!!

Andrea Hernandez said...

Thanks for the post!! My daughter captured one of these guys and we were researching to find out what it is and what it ate. But now-thanks to you-I know the shrub in the backyard is Mountain Laurel and that I need to get rid of these guys. Guess she can have some fun-picking them off.

TexasYankee91 said...

Is a a pesticide that works?

Anonymous said...

Try permetheren (not sure of correct spelling) it works for me it seems to kill every bug known to man

Kathleen Scott said...

I avoid most pesticides because they don't discriminate between good bugs and bad bugs. Texas A&M advises that unless the trees are endangered by extensive defoliation, using strong streams of water or hand-picking the caterpillars will be sufficient.

Kathleen Scott said...

Jane, I should have answered you way long time ago. I've seen them on Necklace Pod; there are probably other related species in the Sophora family.

Brent Mitchell said...

I just discovered these lil guys in August on my mountain laurels....is it normal to see them so late? I've read they mostly attack in the spring...

yogadiane said...

These caterpillars have destroyed an entire crop of my necklace pot plants. I cut them way back. And now that they're beginning to grow back the caterpillars have returned. Please what shall I use to get rid of them permanently ????

Kathleen Scott said...

@yogadiane -- Yes, when I lived in Florida, we had necklace pod damage from genista cats. Try bt (bacilllus thuringencis) but be careful in using it--it will also attack other caterpillars and you could eliminate butterflies from your yard.