Table of Contents
1: Soil Care Basics | 2: Increasing Humus | 3: Maximizing Cover Crops | 4: Bare Ground and Tillage | 5: Plant Care | 6: Beneficial Insects | 7: Habitat Plantings | 8: Other Strategies for Insects | 9: Yet More Strategies | 10: Gardening All Four Seasons | 11: Eating Fresh
Dealing with the Competition: More Strategies
I’ve been talking about growing flowering plants to encourage beneficials. Mulches, in addition to their other virtues, also encourage ground-dwelling beneficial insects such as ground beetles, soldier bugs, and spiders—which feed on snails, slugs, cutworms, potato beetle, gypsy moth, tent caterpillar, bean beetle, and many other insects.
Bats and birds
If you set up bat and bluebird houses, their tenants will assist with insect control. In addition to setting houses of your own making in place, however, you can take care that the general habitat in your homestead is varied. Hedgerows and windbreaks of trees, for example, are great habitat for numerous bird species, many of which feed on insects.
Use transplants when possible
I have said that my strategy with crop plants is: If it’s a species that can be started as a transplant, do so. That strategy has several benefits, not the least of which is that husky transplants with a good “head start” resist insect pressure much better than just-emerged seedlings. For example, flea beetles eat young eggplant seedlings for breakfast. I find that the only strategy with which I can successfully grow eggplants is: Start them under grow lights in the basement, pot them on to larger and larger containers, and protect them from flea beetles either by keeping them in the greenhouse, or on a grow bench more than three feet above ground level (above the “flea beetle zone”). When I finally do plant them as quite large plants almost ready to flower, they can take considerable flea beetle pressure without succumbing. Indeed, studies have found that the loss of up to ten percent of leaf surface to insects can actually stimulate many plants to more vigorous growth.
Where did we get the idea that all the plants for a given crop have to be together? We might do better interplanting many of our crop plants like lettuces, cabbages, broccoli, cooking greens, etc.—or dispersing them into separate parts of the garden. We all know that monocropping in huge agricultural tracts is an open invitation to insect predators of that particular crop to come to the feast! But most of us make “mini-monocrops” throughout our gardens. It is amazing how limited is the range of some plant-eating insects. Thus, separating plants of the same species by as little as a few yards can in some cases make it more difficult for their insect predators to locate them.
Spun-bonded row covers are often recommended to place a physical barrier around growing plants. The idea is to give the plants a greater degree of protection early on, then remove the cover when they are larger and better able to thrive despite attacks by insects. I have also read recommendations from sources I respect to avoid row covers, and allow the interplay between prey and predator insect species to establish their desired balances from the beginning. Perhaps this is an area for interesting experimentation.
Timing of plantings
Some problem insects have a fairly restricted “window of opportunity” in their life cycle when they cause our crops problems. For example, the winged phase of squash borer, a wasp-like moth, lays her egg at the base of the squash vine during a brief period of early to mid-summer. Early varieties which fruit before that time, or plantings made after that time, will not have problems with the borer.
A number of common garden crops grow so fast that they can be planted successively throughout the season to make multiple harvests. With such crops, you can use a succession-planting strategy to bring in your harvests despite your more difficult competitors. For example, squash bug is probably the most difficult problem insect I have to deal with. I plant my summer squashes, do what hand-picking of the bugs I can, harvest my fast-growing squash crop, then allow the plants to succumb as pressure from the multiplying squash bugs mounts. Meanwhile, I have started a succession planting of squashes which are about ready to flower and fruit as the previous planting expires. In this case—with lots of squash bugs already present in the garden—I’m more likely to use row cover to protect the tender seedlings of the succession plantings.
Choice of varieties
You find through experience that some varieties resist insect pressure better than others, and you can use that fact to shape a strategy to eat well even if the bugs are eating well, too. For example, I always start the green bean season by planting both bush beans (I like Contender) and pole beans (McCaslan). The bush beans are much earlier to produce their pods. I make numerous fine pickings from them; but most seasons, they eventually succumb to Mexican bean beetle. I pull the plants and throw them to the chickens, beetle larvae attached, at about the time the pole beans start to flower and make pods. The bean beetles move into the pole beans. From that point until frost the beetles chew the bean leaves to lace, the pole beans shrug and keep cranking out the pods, and Ellen and I have more beans than we can eat. Hey, where’s the problem?
What about purchasing beneficial insects and releasing them into the garden? It’s a great idea—for the people who are growing and distributing the insects. Purchased insects are quite expensive, and after release, you have no control over them—they might just as easily fly over and eat aphids in your neighbor’s garden. You get a much greater return on your efforts by encouraging the beneficial species already native to your place. Of course, it might be fun experimenting with exotic beneficials from time to time. For example, I have used pediobius wasps, tiny wasps that parasitize Mexican bean beetle larvae, for excellent control of bean beetle. The pediobius is not native to Virginia, and will not survive the winters here. They do reproduce effectively in the summer, however, and feed on the beetle larvae. It’s fascinating seeing the parasitized larvae turning into “mummies,” from which emerge—in an amazingly short time—the tiny wasps, who fly off to lay their eggs in other larvae. Most interesting, as said. But as also said, I’m eating plenty of green beans while coexisting with bean beetles, so am not much inclined to continue buying the pedios.