I’m nearing the end of my second summer in a passive solar
house with an 80-foot expanse of south-facing windows. At 7,000 feet, where the outdoor gardening
season can be fickle and short lived, the idea of stuffing our large window planters
with vegetables and enjoying vine fresh tomatoes at Christmas held huge appeal. Little did I know that I was starting a
whole new gardening adventure.
Late fall and my solar palace was bursting with green. Tomatoes crowded four window bays, cucumbers
hung from the ceiling between the kitchen and the window planters, the odor of
herbs filled the air in the late afternoon; this was a gardener’s dream! Or so I thought. First I noticed the peppers. Transplanted starts from a reputable grower,
they were anemic and the fruit wasn’t developing properly – especially for the
amount of warmth and sun they were getting.
Then, the cucumbers between the kitchen and the solar hall declined; I
expect some powdery mildew on cucurbits, but the additional shiny sticky
coating and spider-webbing was a concern.
My research pointed to white flies, and I tried Neem Oil and another
organic pesticide with little impact.
It was Thanksgiving, snow was on the ground yet the tomato
vines crowding the windows weren’t freezing.
To provide the interior of my rowdy tomatoes with air and sun, I
judiciously began pruning non-bearing limbs and some of the larger leaves. I started to notice a suspicious shiny
coating on the vines…a bit of pruning led to major hacking…and tears. The leaves at the windows and the window
sills themselves were covered with a thick layer of honeydew. Devastated, I cut the plants down and tossed
them into the burn pile. A week later, kale
at the other end of the house was covered with little green critters,
stickiness and damage. I collected a
couple of leaves and went over to the extension office to use the microscope.
Hmmm…they looked like aphids, but aphids can be species selective. I didn’t expect all the plants would be
attacked. Our awesome extension agent, Todd
Hagenbuch, sent my samples to the CSU greenhouse entomologist and the verdict came
back: Green Peach Aphids – a wee bestie
that’s particularly problematic in greenhouses and resistant to chemical
pesticides (which I’m not going to use in my living space anyway). The population was substantial enough that
the darn things were reaching the winged adult stage – which explained the
movement through the house. Aphids are
blind, dumb, and barely mobile…but allow them to grow wings and watch out!
The extension expert sent me a CSU paper on biological
control of insects, how they work and where to find them. I made some calls to ‘insectaries’ and
settled on lacewing larvae, an aphid predator.
They come as eggs on cards that are hung near aphid infestations. The
adults don’t seem to do well in greenhouse environments, so I would need to
keep hanging new cards. The lacewings
worked, but my aphid problem was out of control…now they’d found the
bougainvillea! Desperate, I released two batches of aphidoletes
aphidimyza. This is a tiny midge (in the fly family) that flies around
laying eggs near aphid populations on the leaves. The aphidoletes eggs
hatch into tiny larvae (maggot-like) that scoot around the leaves eating
aphids. Within about a month, there was
no honeydew, the new shoots were free of aphids and we could now expect fresh
tomatoes and other vegetables.
It has been a fascinating adventure in allowing what happens
in nature to work in a home. The only
drawback is teeny little flies that are attracted to my late-night headlamp but
it’s a small tradeoff for fresh vegetables all winter long!
Photo by I, Luc Viatour, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=3440776
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