Parasitoids to the Rescue!

Sorry if you’re a little squeamish, but this is too cool to share. Although, I don’t suppose the caterpillar shares my enthusiasm. Last week I found a tobacco hornworm feeding on the leaves of one of my tomato plants. Today I spotted another one. This this one had a problem—a serious problem.

Parasitized Hornworm

See those white things riding on its back? Those are cocoons of a braconid wasp. The Braconidae is a large group of parasitoid wasps. There is at least one that uses tomato and tobacco hornworms as a host for it’s little babies. It injects its eggs under the skin of the caterpillar. When they hatch, the larvae burrow around inside the poor sucker munching as they go until they’re big enough to pupate. Then they pop through the skin, spin a white cocoon of silk and transform into adult wasps that can go on and do that same to more hornworm caterpillars. Isn’t Nature wonderful! The infestation usually kills the host earning the wasps the parasitoid label rather than calling them parasites. I didn’t dispose of this caterpillar like I did with the other one. Here is an opportunity to practice some completely organic pest control. I left them to go about the next stage in their lifecycle protecting the tomato plants of the community garden.

Trouble in the Onion Patch

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I pulled the first onion today! It’s a good size and the top had definitely fallen down which is what I take as a signal to harvest. Lots of onion leaves are toppling.  Whether that’s a good thing, I’m in the process of looking up right now.

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There’s something that looks like a fungus attacking the leaves of the onions. It seems to be spreading from one area making me think it’s something that’s spreading by spores helped out by the near-daily showers we had in June and the cool weather that’s been hanging around. Preliminary investigations are leading me to believe we’re not going to be eating our own onions for a full year like we have been until now.

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I also took a leek in the garden Winking smile Every year I’ve been ignoring them until they’re big monsters so I’m making an effort to eat them as the season goes along. Fingers are crossed that this disease won’t attack them, too.

There was insect activity today, as usual. I’m slowly working at learning what some of them are and, more importantly, who’s a friend and who’s a fiend.

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An obvious friend was this bumble bee hard at work pollinating the tomatoes. Look at that load of pollen!

Bee on Cilantro

This little solitary bee was one of the critters feasting on the cilantro flowers. First, I hadn’t realized how pretty cilantro flowers were until I started looking at these pictures. Second, see her cute little tongue probing the bloom?

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Here’s another angle so you can see how she carries pollen on her leg hairs, not all packed in a ball like the bumble bees and honey bees do.

Fly on Cilantro

This fly was visiting the abundant cilantro flowers, too. I can tell it’s a fly and not a bee because its eyes meet at the top of its head.

Bug on Cilantro

I almost didn’t notice this bug on the plants nestled between unopened buds. There were several of them just hanging out. I saw one on a pole bean tee-pee, too.

Grasshopper on Squash Leaf

This little grasshopper, on the other hand, was easy to spot on a squash leaf.

I’m really enjoying observing and trying to photograph the insects that I’m encountering in the garden. Discovering the burst mode on my phone’s camera has helped a bit in photographing them. It also means I have dozens more images to sort through to see if anything is in focus. There was an amazing fly with a ridiculously long nose working the cilantro blooms that I just couldn’t get because it was moving around so fast. That will be the next challenge to overcome.

For the time being I’m back to researching onion diseases. My fear is that they won’t keep as long as they would have otherwise or, even worse, they’ll need to be discarded right away. Wish me luck!

Pet Sitting

A good friend of mine had to leave town for a while and I agreed to care for his critters while he was gone. The thing is, there are dozens of them. Really. I’m now hosting three species of very hungry caterpillars! One is a single tiger swallowtail, Papilio glaucus. It is a beautiful green and if you look closely you can see a tiny red bindi between its crossed false eyes on its sixth chakra.

The other two species are are giant silkworm moths, a group of large moths with beautifully patterned wings often with large eye spots. Some are polyphemus moths, Antherae polyphemus. These are housed in a converted aquarium so I wasn’t able to get a decent picture and I didn’t want to disturb one by dragging it out. Maybe when they’re larger. And they do get large. By the time they’re ready to spin cocoons they’ll be at least as big as my thumb.

The other species is the promethea moth, Callosamia promethea. These are sort of blue-green right now but will be much greener with red knobs when they’re big.

Last summer I took hosted some promethea cocoons for the same friend and got to see several of them emerge over a period of a few days. I hung them on a little potted tree while they finished drying and expanding their wings. This species displays sexual dimorphism, meaning the males and females look different. The males are the dark ones.

Raising butterfly or moth caterpillars is really pretty simple. You need some sort of container or cage that allows air exchange but doesn’t let the caterpillars escape. Put a layer of paper towels or newspaper in the bottom to make it easier to clean out the droppings. Provide them with whatever leaves they like to eat. To keep the leaves fresh you can use those little water vials florists use for corsages if you’ve got just one or two small caterpillars. For larger numbers, cut Xs in the lid of a deli container and use it like a vase for stems of the food plant. The key is to make it so the caterpillars can’t crawl into the water and drown. Replace the food in fresh water when it’s skeletonized or when it gets stale. Toward the end of their larval stage you’re going to be doing this pretty much daily. They will eat a lot of leaves so have a reliable source. Once they’ve spun their cocoons or formed a crysalis you just wait until the adults emerge either this season or next year after overwintering them outdoors in a rodent-proof container.

I’ll try to keep posting pix of the kids as they grow up. The transformation in size and coloration is a remarkable thing to watch.