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.

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Horrific Halloween Haggis

Halloween is here! Every year I love to celebrate this little holiday by cooking up this old family recipe. It’s a little tricky to get all the ingredients, but the result is a treat!

First, you must obtain a goblin stomach like this one…

Goblin Stomach l

Once you’ve captured and dispatched your goblin—I find a shovel to the back of the skull to be the quickest and easiest way—hack out all the guts to remove the stomach. Save whatever else you might want to grill or broil over the weekend. Try to keep the nerve to the esophageal sphincter as pictured above. It can be used to tie that end shut and keep the filling from leaking during the boiling.

Next, chop together some oats, suet and…oh, I can’t do this to you. This is really a, actually “the” sweet potato I got from the the garden this year. Despite planting three healthy starts gifted to me by a fellow gardener and surrounding them with metal mesh to thwart burrowing vermin I got next to nothing. The biggest problem was an unanticipated aboveground assault. Voles, I suspect, ate off all the leaves from the vines and in some cases chewed through them completely leaving the roots no way to obtain and store nutrients in nice, fat tubers. I may or many not steam this little fellow for some appetizer. And I may or may not try growing sweet potatoes again in the future. If I do, I’ll certainly take measures to protect them from gobblin’ rodents!

Bugging the Bugs that Bug the Beans

About five weeks ago I started seeing something on my bush beans. I was expecting them and knew what to look for.

Those pretty yellow bumps are the eggs of a Mexican bean beetle. The adults, which I don’t have any of my own pictures of, resemble ladybugs. They are related, but the bean beetle has more of an orangey color and small spots in horizontal bands.

When the eggs hatch you can find the larvae feeding on the underside of leaves. They’re yellowish as well and are covered with spines.

The adults and larvae feeding on the leaves of the bean plants can obviously do a lot of damage. What I find interesting is that they appear to like some varieties of beans more than others. In this picture there are three rows of beans. From left to right they are Black Valentine, Jacob’s Cattle Gasless and Lina Cisco’s Birdsegg.

Three Beans

Notice anything? It looks like the beetles don’t especially care for the Black Valentine compared to the other two. They’re also more or less leaving my white kidney and pole lima  beans alone.

So how does one control them in an organic garden? At first I was doing the simplest approach—removing and destroying the eggs and adults whenever I found them. But given the number of bean plants I have and the fact that I can’t get to the garden every day that approach wasn’t going to do much.

Here’s one of the advantages of having a plot in a community garden. I and several other gardeners on the committee were charged with monitoring our bean plants and reported when the first eggs were spotted. Whoever was in charge of such things then ordered some predatory wasps that, being really, really pricey are out of the range of most home kitchen gardeners. The timing of the wasps’ release is very important so they are shipped overnight just before they emerge.

 

A little mesh bag is hung inside the bean plants (I moved this one out for a picture) so the wasps don’t have to go far. They’re very tiny and I haven’t seen any. The wasps lay their eggs in the bean beetle larvae where they hatch, feed on the beetle thus killing it, pupate and then emerge to start the cycle all over again on more larvae. These little buggers are gruesomely effective. This is the third year I’ve been growing beans here and the first time the beetles have been noticeable. The wasps have been used in the past and other gardeners report that they worked very well in knocking back the beetles for several years. My plants are forming beans that should mature and be harvestable. With some luck next year’s crop won’t have to suffer this kind of infestation.

Using the wasps to treat for the beetles is an example of a biological control. Do you employ biological controls in your garden?

Onion Bandits!

The onions have grown, to put it mildly. It shouldn’t be surprising, but I can’t help marveling at the fact that the wilty, pencil-thick plants I stuck in the ground a while back have turned into the pungent orbs I regard as a vital kitchen staple. A few are larger than anything I’d pick up in the grocery store, as large as a softball, or so I’m told by certain women we know.


The onions have been pulled and were curing in the sun/shade on the deck before going into storage. Unfortunately, certain striped rodents decided they would try tasting the produce. In the end they were thwarted by none other than the softball-savvy women we’re lucky to have in our home right now. Garden Justice prevails, and future meals will be a testament to their bravery.