Naturally Bug-Free (5 page)

The table above suggests some plants that are particularly good for attracting pollinators, focusing on species that you may already have growing in or around your garden. When choosing pollinator plants, remember that showy, cultivated flowers (like irises and modern roses) have often been bred to reduce their output of pollen and nectar, so wildflowers or old-fashioned cultivated plants (like single-petaled roses) are a better bet for your pollinator garden. Members of the carrot, mint, and aster families, with their many tiny flowers in each head, are particularly useful if you'd like to attract the smallest pollinators. You should aim to have at least three different types of plants blooming in the spring, three in the summer, and three in the fall, and should be sure to cover the very early spring and late fall when pollinators are often in dire need of food.

Some pollinators lay their eggs inside hollow stems, which they fill with food for their young before capping the ends with mud. You can make simple nest bundles for your bees by cutting bamboo of various diameters, making sure that one end is plugged by the node and the other end is hollow. Hang your nest bundles horizontally under your eaves or in another dry spot, and bees will move in over the summer.

Next, ensure that the wild pollinators have nesting sites available. Although you can build nest sites for pollinators, just letting the stems of plants like sunflowers and goldenrod stand through the winter will help out many species. Some pollinators need patches of bare soil, while yet others require a bit of nearby woodland. In general, letting the edges of your yard go wild will do the work of attracting native pollinators for you.

Butterflies are drawn to areas high in salt, like drying puddles, damp manure, or spots where humans or animals have urinated.

If you want to get a bit fancier, you can make a butterfly feeder...by peeing on the ground. Although nectar is a high-energy food source, it tends to lack salt, so butterflies and other nectar-eaters need to track down another source of this important nutrient. Male butterflies, in particular, spend a lot of time puddling—gathering around drying puddles or other sources of salt. Later, the males will pass a package of salt to the females as a gift when they mate.

The greater bee fly (
Bombylius major
) is a good pollinator, but the insect also parasitizes solitary bees and wasps.

Of course, as in the world of the soil, not all pollinators are purely allies of the garden. For example, the pollinator shown above is a fly that mimics a bee. Since the species appears so bee-like, the greater bee fly is able to get close to the burrows of solitary bees, into which it flings its eggs. When the bee fly eggs hatch out, the larval flies feed on the larval bees, often killing the latter. However, as with most parts of garden ecology, bee flies still have an important spot in the ecosystem—there's no balance without predators as well as prey.

Predators

The ladybug is the classic garden predator. One of our readers attracts ladybugs early in the season by growing bachelor's buttons, and he finds that his efforts result in a healthy ladybug population for the rest of the year.

Speaking of predators, the third group of wholly-positive invertebrates is the bugs who consume bad insects. Spiders, centipedes, dragonflies, mantids (aka praying mantises), ambush bugs, assassin bugs, lacewings, ladybird beetles (aka ladybugs), ground beetles, true wasps, digger wasps, hoverflies, and robber flies all subsist primarily or entirely on other insects during some stage of their life cycle.

Praying mantises eat both good and bad insects. It's handy to know what their egg cases look like (bottom photo) so you can leave the spongy structures behind when pruning fruit trees.

Although many of the species listed above are generalist predators, eating whatever ends up in front of them, all of these insects help keep pest population explosions in check. For example, I accidentally let the beetles on my green-bean plants get out of control one summer, and soon thereafter I saw a pair of praying mantises move in to take advantage of the bounty. Sure, the mantises might have been eating butterflies yesterday, but I consider them beneficial insects because they eat at least as many bad bugs as good.

This hornworm is further along in the parasitization cycle than the one I pictured earlier. The caterpillar is dead in this photo and the wasps are getting ready to hatch out of their cocoons.

Another category of predators is the parasitoids. Braconid wasps, ichneumonid wasps, chalcid wasps, and parasitic flies all lay their eggs on other insects, and unlike true parasites, the wasps and flies eventually kill their hosts. That's great news in the garden since many of the prey insects are bad bugs, like tomato hornworms or bean beetles, so the parasitoids keep the pests under control. As a side note, in case you're scared of the term "wasp," all of the parasitic wasps are too small to be a problem for human gardeners.

Pediobius foveolatus
wasps parasitize Mexican been beetle larvae, but you have to buy these tropical wasps each year to protect your bean planting.

Many gardeners fall in love with the idea of predatory and parasitic insects and decide to buy some of these critters to seed their garden. However, I believe that you really need to encourage all of these species at the ecosystem level. I've heard of people opening a container of expensive insects, only to have them all fly away because the garden isn't a hospitable environment for the predators to live in.