hornworms on vitex

has anybody had experience with hornworms on their vitex trees/bushes? i just put these plants in the ground this summer, so they aren't very big yet and can't handle a total strip-down (yet), being too young. anyway, i was under the impression that vitex were relatively pest-free. imagine my surprise when yesterday i found 3 hornworms devouring a couple of plants. i picked them off and threw them in the lake and i can always use bt if they get really bad, so i'm not asking for a solution, just a question on anyone else with the experience.

This message was edited Aug 31, 2006 9:10 PM

I haven't had any on my Vitex, but I would probably move them to something else because they turn into those neat hummingbird moths. If you use bt it will kill all cats, good and bad.

in my mind, these guys are bad. at least they are not in my top ten favorites! anyway, there was only three and i can hand-pick with tongs. if i sprayed with bt, it wouldn't hurt anything else, because there aren't any other cats around there.

what i really wanted to know is why a tomato hornworm would be on vitex in the first place. it's in the verbena family and i didn't know that hornworms ate verbena.

It would be a surprise if these really were tomato hornworms. I get surprised all the time, however, so that doesn't mean much. The whole sphinx moth family Sphingidae produces caterpillars that have the typical horn (its harmless) on the rear. There are over 120 species in America north of Mexico and lots more in the tropics and so there are plenty of other choices.

This reference says that Vitex are not larval host plants:
http://www.huffmantaxidermy.net/oehlke/jcVitex_agnus-castus.htm
which we now know is not right anymore, but this reference:
http://www.silkmoths.bizland.com/mflorest.htm
indicates that Manduca floristan has used Vitex megapotamica as a host. M. floristan does not appear to occur in Florida, but it is interesting to note that Manduca is the same genus that the tomato hornworm is in. Once your Vitex get big enough to support a couple of these caterpillars, you might have a new record one way or another.

FM

thanks for the info. i will keep an eye on these plants. normally we don't get more than a couple of them a year on our tomatoes and the summer crop has been pulled for about a month now. i don't expect to see any more on the vitex this year as we are coming into fall, but next year i will be on the look-out and take pictures if they arrive.

Hi Trackinsand,

I found a hornworm on my Vitex and this thread came up in my search....it is indeed a hornworm, it is Manduca rustica rustica (Rustic Sphinx hornworm). They are found from Virginia south to Florida and across the west from Arkansas to southern California....they dine on Vitex, and other members of the Verbena family like Aloysia (sweet Almond).

http://www.silkmoths.bizland.com/mrustrus.htm

thanks for that link, moon!
i see one once in a while on the mature Vitex now and just leave them alone. it's nice to finally know what it is.
hill got the genus right and you've supplied the mystery species!

And it only took 7 years....LOL.

You are most welcome.