06 July 2009

On Safari

After one entire week without a single ray of sun, we breathed a deep sigh of relief and exhilaration when the clouds and heavy fog finally broke this morning. I could just feel the plants growing, the robins and wood thrushes broke into a loud chorus, and my downcast mood was instantaneously replaced by the same chatter and activity as the birds and the bees. What a difference a little sunshine makes!

And just in time too, the peas were beginning to rot at the tips, due to water-logged roots, the first crop to show water stress in our garden.

Not much has been going on in the garden these last few weeks, with little to weed and even less to harvest, I've been going on safari. We walk the garden every day, to watch for signs of insect damage or disease. This is often done in the course of harvesting ripened produce and weeding, but I also keep a close eye on insect diversity, dispersal and populations in the garden as a part of my own experiment on how well beneficial insects are able to control pest insect numbers.

And it's a jungle out there. I have found a number of new and interesting critters, along with familiar allies. And for some reason or another, the most biologically diverse and productive area of the garden has been in the potato patch. I suspect it is the universal allure of the plump and slow-moving Colorado Potato Beetle larvae. The always remind me of the insect world's equivalent of a herd of grazing cows, and what wolf or coyote can resist?

We handpick the adult beetles (from 5-20 a day), and squish the little larvae when we see them, but surprisingly few larvae are either hatching or growing very large due to the numerous predators.
Including this Harvestman (or Daddy Longlegs), they are general predators and scavengers. I think he had his eyes on that plump potato beetle larva through the foliage in the distance.


Even the eggs are being eaten by something or other, it's hard to know who... they do look pretty tasty.

It could be these Long-Legged Flies, numerous in the potato patch, they will eat both eggs and beetle larvae.

Another friend, spotted often resting in the dense foliage of the potato patch, this Slug-Killing Fly or Marsh Fly (of the Tetanocera family). They are parasites of slugs and snails, of which there are plenty due to the wet spring. Adults lay their eggs on slugs and snails, and feed on nectar or pollen, offered by the blooming potato flowers.


Another predator found hunting the potato jungle, an Ichneumonoid Wasp. This rather homely specimen does not compare to the more graceful and colorful Braconid Wasp spotted in the garden, and too elusive to photograph.

Outside of the potato patch, carrot flowers never fail to attract allies. The metallic and pastel shades of this Predatory Stink Bug or Spined Soldier Bug contrast well with the budding carrot flower, rather pretty isn't it? Not only pretty, but a very good ally in the garden, with an appetite for some of the most discouraging pests. "Over 100 species in many families have been reported as prey. Prime targets are immature insects. Reported prey include the larvae of Mexican bean beetle, European corn borer, diamondback moth, corn earworm, beet armyworm, fall armyworm, cabbage looper, imported cabbageworm, Colorado potato beetle, velvetbean caterpillar, and flea beetles."

Everyone loves a Lady Beetle. Even those who are squeamish about bugs cannot find much fault with this Seven-Spotted Lady Beetle. It's probably the absence of any creepy looking legs, antennae, stingers, proboscis, spines or slime that win the hearts of every gardener. We don't have many aphids in our garden, but there's always a Lady Beetle or two around. Mostly these and the Three-Banded Lady Beetle.

Scavenging the ground level of the garden, I can hardly disturb the soil without finding one of these hard-working Ground Beetles. This is the largest, and earliest emerging Ground Beetle species in our garden. But it has been accompanied by two or three other species, including a smaller bronze colored one, and a smaller plain black one.

And this iridescent species. This picture shows off their mouth parts, wouldn't want to be a soft-bodied insect in their way. They have been doing very well this year, feeding on the abundance of cutworms in the soil. I often disturb one dining on a grub, and in one heavily infested bed, where I found 100 cutworms, I disturbed about 25 Ground Beetles. Not a bad predator to prey ratio.

Also numerous and widespread are these mother Wolf Spiders. They are general scavengers, will catch prey or eat insect eggs in the soil, including Grasshopper eggs. From what I've read, dozens of little bitty-spiders will emerge from these egg sacs, and the mother spider will continue to carry them around on her back until they are large enough to fend for themselves. I find about one of these sack-toting mothers about every 100 square foot of garden, so there will likely be hundreds of hungry teenage spiders, scavenging the garden soil this summer.

Another maternal insect, the White-Margined Burrowing Bug. She is not a predator, but caught my attention with the dozen or so nymphs riding around on her back. They are related to the Stink Bug (or True Bug), but burrow in the ground instead of staying in the canopy like their cousins. And they verge on the pest side, as sap suckers, or root eaters, but are not known as a major pest.
And for a finale, the strangest critter found in the garden this spring: Strauzia longipennis, the Sunflower Maggot Fly. Entomologists must have a sense of humor. *giggle* Not surprisingly, it was found on the sunflowers, laying eggs on the undersides of the leaves. The eggs will develop into maggots, eating leaves or seeds, depending on the species. Until I hunted down the identification of this particular insect, I was unaware that sunflowers had a specific pest (besides Blue Jays), so I will be watching for any maggots or leaf damage on my sunflowers.

I hope you have enjoyed this safari tour of hunters and hunted in the garden. Keep prowling around in your own.

Overall, I am each year, impressed with the diversity and population of predators, scavengers and parasites in our garden. And to encourage their cooperation I have been researching their specific life cycles, food and overwintering needs. I have found that all the information I need can be searched on the net, but it is not compiled, all on one site, that I can continue to refer back to when needed. So I am keeping the information I collect on two spreadsheets, one for beneficials and one for pests, specific to my own garden bio-diversity. I am sure they will prove to be handy reference charts while planning, rotating, planting and cultivating the garden.

Included in the pest chart I have a column for each of the following: Taxonomic Family name, Visible Crop Damage, Feeds on as larva, Feeds on as adult, Natural Enemies, Hosts On, Life Cycle, Overwinters As, Control Methods. The beneficials chart includes columns for each of the following: Taxonomic Family name, Feeds on as larva, Feeds on as adult, Hosts On, Life Cycle, Overwinters As, Attracted or Maintained by. In these charts I list my own experiences with controlling or attracting insects, as well as methods established by generations of gardeners. You may find this a helpful tool in your own garden.

4 comments:

slowcoast said...

Great post! Great photos!!

Are you planning to publish your pest chart? :-)

ChicagoMike said...

Great post with great pics.

Do you have a macro lens?

randi said...

another very useful post, thank you! It's funny, as my eyes are getting less reliable for on site identification I am discovering my camera helps heaps when I download and 'see' magnified what I've taken a pic of..I really appreciate how you've compiled all this info,it's a terrific reference.

Freija and Beringian Fritillary said...

slowcoast, Thanks! I was thinking of putting them up as a wiki. I have only concentrated on the major pests and beneficials in our area, so it could be expanded by others, with the format already set. Also, control methods for pests and ways to attract beneficials can always be updated and expanded. So that's what I was thinking of doing over the winter months.

ChicagoMike, thank you. I just use the close-up setting on a little 5.1 Megapixel 3X Zoom digital camera. It can be reluctant to focus where I want it to, but most of the bugs are pretty patient with me. Then I take the pics and crop/zoom them some more at the computer.

randi, you're very welcome! The camera definately helps, some of those little guys look pretty similar. If this bug-nerd's obsession comes in handy for fellow gardeners, I'm gratified. ;)