Posted by Tanya Weisinger on October 12, 2007

Q: I live in Houston and have recently bought a lemon tree. I've had several Orange Dog Caterpillars (the ones that look like bird poop) on my tree. I don't mind them eating the leaves, actually enjoyed that fact I was helping in the butterfly population. I've seen a couple grow up and move on. There were always fresh eggs and baby caterpillars (maybe 5-6 at a time some times). Just last week, the 3 caterpillars on the tree that ranged in size just died within a couple of days of each other. They are still hanging on the tree but have just fell to the side and died. I did find one super small one that must have just hatched that was eating away. He hasn't died. Any ideas as to why this happened? There is still plenty to eat (plenty of greenery) on the tree. They actually didn't eat as much as I'd thought they would. It also has rained off and on so I don't think they dehydrated (if they can do that). The weather has gotten a bit cooler, in the 60's at the coolest part of the night. Thanks for any information. I'm excited about planting a butterfly garden in the future.

State: Texas

Habitat: suburban/yard

A: >

> Giving you a definitive answer as to why they've died is not possible but I can make an educated guess. Can I assume that you have NOT sprayed the tree with any substances? I realize that this may sound like a dumb question but anything added to the tree - good or bad - at this time could be an issue here.

> Here in the East we have a large population of Gypsy Moths that waxes and wanes on about a 7 year cycle. There are several variables that probably cause their population crash at the end of this cycle but one big one is a bacterium that infects the caterpillars. In a large population, the bacteria are much more easily transmitted from one individual to another so the disease can race through the population and then of course their deaths from this bacteria is also more noticable just due to their large numbers. My guess is that your caterpillars have contracted some kind of disease and since you've been keeping an eye on them, noticed their deaths. In nature this kind of thing goes on all the time but we rarely see it. As I mentioned earlier, I can't say this is the reason (some kind of bacterial infection) but this is what I would suspect before anything else if we can eliminate any sprays etc to your tree.

Nice to see that you've enjoyed these interesting caterpillars and were willing to lose a few leaves on their behalf. Let's hope your small one doesn't have the same fate as the larger animals. Thanks for sharing and I hope this helps a bit.

>

John Wiessinger ( October 13, 2007)

A: Tanya,

Just realized your name is very close to mine. Wow! Thanks again for writing.

My best,

John Wiessinger

John Wiessinger ( October 13, 2007)