A Different Kind of Hornworm

 One of the neighbors who's using the veggie beds in my backyard showed me a large caterpillar she had found in the raised bed behind the garage where Cindy had been growing raspberries and blueberries.  Because of the large yellow horn on one end of the caterpillar, I figured it was some variety of hornworm.

We've had hornworms before, both Tomato Hornworms and Tobacco Hornworms.  They're the larva of different types of Sphinx moths.  See A Tasty Snack For the Birds and Big Green Worms.  The way I remember which is which is that the Tomato Hornworms have chevron stripes on their sides and the Tobacco Hornworms have straight stripes, again on their sides.  

This one was different, though.  The stripes on this caterpillar were long racing stripes along its back and no stripes on its sides.  

A quick search on the internet indicates that this might be another type of Sphinx moth, probably the White-lined Sphinx Moth.  Adult Sphinx Moths are pollinators, feeding on nectar of flowering plants, usually at night.  The larva feed on a variety of plants, including chickweed, purslane, evening primrose and other plants.  

I usually pull hornworms off the tomato plants and leave them under the bird feeder as a snack for the birds, but since this guy was not in any of the beds with tomato plants in them, and since the White-lined Sphinx Moth larva eat weeds, I put him back where I found him.  

He's welcome to any weeds he wants to eat.  Just as long as he stays off the tomatoes.  

Big Green Worms

Tobacco Hornworm

Another thing we found when we got home was a couple of enormous Tobacco Hornworms  happily devouring the leaves of the Boxcar Willie tomato plant.

I was able to get some good pictures of the insect, so we were able to determine that these are the Tobacco Hornworm (Manduca sexta), which has seven diagonal stripes on its sides, rather than the similar Tomato Hornworm (Manduca quinquemaculata), which has eight chevron-shaped stripes.  As easy way to remember this is that the Tobacco Hornworm has stripes that are straight, like a cigarette, while the Tomato Hornworm has v-shaped chevrons that remind you of vine-ripened tomatoes.

Not that it matters all that much, because both worms have voracious appetites and either of them can strip the leaves from a tomato vine in pretty short order.

Since the tomato plant was at the end of its very productive season, Cindy just decided to take it out and make the bed available for winter crops.

And the hornworms?  She left those under the bird feeder for the birds to finish off, which they promptly did with enthusiasm.

A Garden Without Caterpillars

Monarch Caterpillar

We've had plenty of Monarch butterflies visiting our front yard butterfly garden all summer, but until recently we had seen no Monarch caterpillars.  The Asclepia plants are all thriving this year, although by now they should have been nibbled down to bare stalks by the caterpillars.

We would think it was just our yard, but other Master Gardeners in San Diego are reporting the same problem in their gardens:  no Monarch caterpillars.

We saw two small ones about a week ago, but they are gone now.  They were both too small to have pupated already, so something is clearly still nobbling our caterpillars (I learned that word from watching the delectable British TV series Pie In The Sky).

It might be the Lesser Goldfinches, as we saw one trying to imitate a hummingbird as she attacked a huge Tomato Hornworm in the back yard a couple of weeks ago.  She wasn't afraid to go after that enormous worm, but she also didn't succeed in getting it off the tomato vine.

Another suspect is the same one we considered last year at this time:  wasps.  We haven't seen any of the Mud Dauber wasp nests this year, but the Paper Wasps in the back yard not only revived their old nest from last year, but also constructed a large three part wasp condo under the patio cover.  You would think they could have taken out that hornworm, but noooo.

One thing I don't think we'll try again is the caterpillar cage we tried last year when we were having the same problem (See Co-dependent to Caterpillars, Part II).  As the subsequent posts from October and November of last year show, that effort was pretty much of a disaster, so I think they'll just have to figure it out on their own.

We'll probably have to hire a pro to get those wasp nests down, though.

A Tasty Snack...For The Birds

Hornworm In Action

We were having lunch on the patio the other day when Cindy spotted a yellow bird among the leaves of the tomato plant nearest us.  The bird was a female Lesser Goldfinch, and at first we thought she was trying to add some salad in the form of tomato leaves to the Niger Thistle seed from our feeders.

As we watched her trying to hover in the air as she pecked at some of the leaves, we realized that she wasn't after leaves at all; she was after the enormous Tomato Hornworm that was chowing down on the tomato leaves.

She managed to take a pretty good chunk out of the Hornworm, but she flew away before she actually got the Hornworm off the branch, although that was enough to draw our attention to its presence.

Since we thought that was by far the best way to dispose of this pest, Cindy clipped the leaves off the tomato plant and left them, with the damaged Hornworm, under the bird feeder for the birds to finish off.  After about an hour, there was no sign of the Hornworm, so somebody took care of it for us.

Hornworm Down

A tasty snack for them and no more damage to our tomato plants.

Codependent to Caterpillars, Part II

Butterfly Garden

We love our front-yard butterfly garden, especially when we see several Monarch butterflies at once enjoying the flowers and bushes we've put there to attract them.

In fact, we've had lots of Monarchs this summer flying around and landing on the Asclepia, the lavenders and the Buddleia.

What we haven't had is what makes butterflies:  namely, caterpillars.  The Asclepia plants were flourishing, but with all those Monarchs fluttering around, they should have been all but stripped of leaves.  But they weren't.

After the disaster of the Anise Swallowtail caterpillars we found on the parsley in the back yard, probably gobbled up by the Scrub Jays that hang around our bird feeder, we relocated some several Monarch caterpillars from an Asclepia plant in the back yard.  When they, too, disappeared, we began to think that maybe it wasn't just the Scrub Jays eating our caterpillars.

Wasps, lizards, ants and other predators eat caterpillars and we now suspect that the Mud Dauber Wasps that have built nests all over the eaves of our house may be responsible for the disappearance of the Monarch caterpillars.  (Caution:  that article is fairly graphic--don't read it if you're squeamish--it's like something out of "Alien").

The good news about these wasps is that they prefer to use spiders, especially Black Widows, to feed their larvae; the bad news is that they will also use butterfly caterpillars.  That's O.K. with us if the caterpillars are the larvae of the Tomato Hornworm, laid by the Sphinx Moth, but not O.K. if it's our Monarch caterpillars.

So, to protect at least some of the Monarch caterpillars, we finally bought a butterfly cage, a soft-sided mesh cage to protect them.  The cage has a clear plastic side and three mesh sides, one of which has a zipper to form a door on that side so you can open the cage.

Last Tuesday we put two fairly large Monarch caterpillars into it with some of the Asclepia in a bud vase with water.  Cindy wound plastic wrap around the stems of the plants so the caterpillars wouldn't crawl in and drown, which was probably a good precaution:  I don't think they can swim.  Then the next day we found two more caterpillars and moved them in, using a rose bud vial with a rubber lid.  We put stones in the bottom to keep the whole thing from blowing over in the wind.

By Friday the first caterpillar had crawled off the plants and attached to the cage to form a chrysalis.  Naturally, since nothing is ever easy, Numero Uno decided to attach and form his chrysalis very close to the zipper, which made it very difficult to open the cage to put fresh plants for caterpillars Two and Three.  Number four was very small and we never found out what happened to him, but Two and Three were eating everything in sight, so we had to slide the fresh plants in very carefully.

So that's the story so far.  Today Number Two is crawling all over the cage, looking for a suitable place to attach (NOT near the zipper, PLEASE!), and Number Three is still eating everything is sight and will probably attach soon, too.      

Path of Destruction

Tomato Hornworm

I ran across this photo Cindy and I shot three years ago.

Some of her tomatoes were not doing well, so she started investigating and found this suspicious looking hole in the stem of one of the failing plants.

When she sliced the stem open, she found a path of destruction throughout the stem and finally located the culprit:  a tomato hornworm.

It was unexpected because hornworms usually just chow down on the leaves and stems from above, but this one evidently decided to go inside, thus evading detection for a while.

Cindy used to dispose of them by throwing them over the hedge into the canyon, but now she just picks them off the plant and leaves them on the stones under the bird feeder.  The birds do the dirty work for us and they get a tasty snack.  Works for us.