Our Frenemies in the Garden
On a cool evening, our garden coordinator Cindy led a guided tour of the garden’s bugs.
We coexist with beneficial bugs. We eliminate those that destroy crops using organic practices.
During the recent Bug Walk we found the spotted lady beetle, which eats aphids, just like her cousin the regular ladybug. Other beneficial bugs who eat the grubs, eggs, and even adults forms of destructive bugs include spiders and wasps. Bees, wasps, butterflies and moths are primary pollinators. Though not technically bugs, worms are also a very valuable creepy crawly found in the garden.
Ground nesting bees and wasps in the garden won’t harm plants, but they will sting us if we disturb or step on them. Each can sting multiple times. If we find a ground nest in the garden, we’ll smoke out the residents, fill the nest, and encourage them to relocate in the field.
In feeding themselves and their young, these bugs will ruin crops for humans:
- Cucumber beetles
- Flea beetles
- Japanese beetles
- Potato beetles
- Swede midge
- Tomato hornworms
- White grubs
- Wireworms, a/k/a click beetles or meal worms
Some of them resemble the plants they eat. Even hornworms, which grow to the size of an adult’s thumb, can be difficult to see. Others are sneaky.
When beetles feel threatened by a human hand coming to pick them off a plant, they’ll drop straight down into the dirt and hide until the threat passes. One way to outsmart beetles is to hold the bug-collecting jar under the beetle, then tap either the bug or leaf gently so it drops into the jar.
The best time to remove bugs is when they’re mating and breeding. That’s when they eat the most and also deposit eggs on and into plants. So bug-picking also means egg-picking.
After eggs come larvae. Potato beetle larvae are voracious. We’ve stood and watched them eat right through leaves.
Brassica – including kale, Brussels sprouts, broccoli, cauliflower, and cabbage – are vulnerable to swede midge and flea beetles. Swede midge live in the heart of plants and require a hand lens or microscope to see. The grubs eat the plant growth nub, then excrete noxious stuff.
This community garden uses organic growing practices. We do not bring any poisons into the garden.
White grubs eat plant roots, and get mashed as gardeners find them. We collect other destructive bugs in bug jars filled with soapy water. Unearthing bug eggs means putting the entire leaf they’re on into the bug jar. The soap is biodegradable. Eventually, we pour the bug jars into the compost.
We also hang Japanese beetle traps.
When squash and cucumbers are planted in boxes, we dress them up in little plant hats to protect them from cucumber beetles. That gets the young plants past the mating and larval season.
Wireworms will eat holes in potatoes, tomatoes, peppers, and eggplants – all plants classified as solanaceae. Wireworms can be “trapped” by planting yucky old potatoes in garden beds, which will attract the worms. Then the old potatoes can be dug up and disposed of – burned, discarded, or otherwise kept out of the garden and compost until the worms no longer threaten the plants.
Sifting diatomaceous earth onto plants and garden beds will stop snails, whitefly, and flea beetles. They might have some effect against swede midge, but they are mainly vulnerable to poisons, which we won’t use.
Fully squashed bug remains go into the compost for extra nutrients, as long as no live bugs or snails or viable eggs remain. Wireworms can be cut in half and left in the soil, which might deter other wireworms.
Mosquitoes we avoid simply by eliminating standing water in the garden. We tip over buckets and troughs, and store wheelbarrows on their sides.