Aphids on the Arugula?

One of my friends brought some arugula leaves to the office last week, to show me the many hundreds of aphids that were on them. The arugula is growing at a community garden that she had visited, and she had permission from the gardener to pick a few leaves.

Aphids on arugula from local community garden. PHOTO/Amygwh

We slid the leaves under the microscope and could see that, while a whole lot of the aphids are alive and active (the green ones in the picture), some had been "parasitized" by a wasp.

That means that a little wasp had laid an egg inside the aphid, and the egg was developing into a new wasp.

The aphids that have a baby wasp inside are the puffed-up golden ones in the picture.

When each wasp-baby is mature, it will bust out of the aphid body, leaving behind an empty aphid shell.

Are images from "The Alien" movie flashing through your mind yet? Sometimes, real life is just as weird as science-fiction movies. This is part of what keeps gardening so engaging.

In organic gardening, knowing that there are predators and parasitic wasps around, waiting to take care of a pest problem, provides an odd kind of comfort. Unfortunately, though, even if a swarm of ladybugs (surprisingly effective predators on aphids) moves in to help the wasps clear up the aphid problem, this arugula is going to need a lot of washing before it is added to a salad.

My venerable copy of Rodale's "The Organic Handbook of Natural Insect and Disease Control" (my copy is from 1996) offers some help for aphid infestations. The first suggestion is to wait for the predators to take care of the problem. Usually, in my garden, "waiting" is enough.

This is an odd year weatherwise, though, so it looks as though more active steps will be needed in some gardens. The next suggestion is to blast the little plants with strong spray from a hose to knock the aphids off. The next after that is to try an insecticidal soap spray. In a dire emergency, try a veg-garden-pest spray that contains neem.

Of course, the very first thing to have done, if anyone could have foreseen the aphid disaster looming from back in the fall, would have been to cover the little crop with a spun rowcover to keep the aphids out completely.

Hoping that other gardens are relatively aphid-free!

A Movie for Pollinator Week (3rd week in June)

One aspect of vegetable gardening that sometimes surprises new gardeners is finding out that many insects and other small creatures provide important support to the garden's health and productivity. Most gardeners are not "in it" for the bugs! 

However, as a gardener,  I have learned a whole lot about insects and other critters. Some of these are pretty strange-looking and may seem a bit unlovable, but quite a lot of people appreciate the beauty of butterflies. 

Monarchs Across Georgia, a group that has a mission to study Monarch butterflies and restore butterfly habitat, is hosting a viewing of the Disneynature movie Wings of Life as part of its celebration of National Pollinator Week. The movie, which is rated G, runs 77 minutes.

To defer costs, the group is asking for a donation to the Environmental Education Alliance of Georgia (the group's "parent").

The movie will be shown on Saturday, June 25, 11:00 a.m., at the Midtown Art Cinema in Atlanta (931 Monroe Drive, NE, 30308). A theater seat can be reserved online.

The description of the movie included in the ad-copy on the MAG website is this:

Released as part of Walt Disney Studios' Disneynature banner, filmmaker Louis Schwartzberg's documentary employs macrophotography in order to show moviegoers a world they have likely never experienced. The secret lives of bats, butterflies, hummingbirds, and bumblebees come to life before our eyes as Schwatrzberg and his talented team highlight how the determination and interdependence of these diminutive creatures keep our chaotic world in balance.

An Educator's Guide webpage for the movie offers a download-able activity booklet and lessons designed for grades 2-4, and additional film clips are available there, too.  

The trailer for the movie is available online.

At the theater, native Georgie milkweeds, the host plants of the Monarch butterfly, will be available for purchase.

See you there?

 

Insect Activity This Week

Insect activity in the garden can be good, and it can be unwelcome, depending on the insect. This weekend, I made the first sighting of the season of a most unwelcome moth, the squash vine borer. She is pretty, but her babies devour the insides of squash vines, eventually leading to the demise of the plants.

Squash vine borer adult. The red can be viewed as a warning to gardeners!

Where the Pollinators and Predators Hang Out

The picture below isn't from my yard. Joe and I walked around our local park last Saturday, and there were butterflies, bees, wasps, and other great insects on all the flowering weeds.

Not my yard, but great to see a Monarch butterfly near home

It made me wonder how much my own garden's success depends on the city's not mowing edge-to-edge in my local parks.

When food gardens have a problem with low productivity, it sometimes can be traced to a scarcity of pollinators. A lot of newer neighborhoods are border-to-border monoculture lawns. These yards are pretty low on habitat that would support useful populations of pollinators and other beneficial insects.

Most gardeners understand that this is a problem, and they follow guidelines like those in  UGA's publication Beyond Butterflies: Gardening for Native Pollinators to plant small-flowered herbs and other pollen-and nectar-rich flowers that attract pollinators and useful predators, but if the insects don't have a good place to reproduce and to survive the winter, there might never be an abundance of these useful critters.

My garden crops typically don't have a problem with lack of pollination, and there seem to be plenty of great predatory insects, too, but, like all those other gardeners, I do what I can to attract a diverse community of insects and other small creatures to my own yard. Also, I am lucky in that my yard backs up to a small patch of woods and that it has a creek -- with associated native vegetation -- running along one side. I am sure that all helps.

According to a recent article posted at Southern Region IPM News, The Right Habitat and Food Source Key for Beneficial Insects, that describes findings of entomologists at North Carolina State University, the parasitic wasp Telemonus podisi (it kills stink bug embryos) overwinters more often in leaf litter than in cracks of tree bark:

“The number of parasitic wasps, for example, was four times greater in leaf litter than those overwintering in tree bark,” said Lahiri. “This data, combined with lab studies, suggest the importance of woodland field borders with leaf litter from hardwood trees as a refuge area during winter for the parasitoids.”

I do have some woodland edge, but -- even combined with the right garden flowers -- the wild spaces in my one yard may not be enough to support all the beneficial insects that help out in my garden.

Wouldn't it be something if the unmowed and uncleared edges of city and county parks were the best refuges for our beneficial insect populations?