Pests and diseases 65
Beneficial insects
Likewise, when you see orange beetles on your echinacea and heliopsis, don’t
spray them with the fear that the beetles are going to destroy your perennials—
let these beneficial soldier beetles do their part in helping combat pests. Benefi-
cial insects can help you control pests in your garden naturally. Encourage them
by planting perennials that produce a lot of pollen or nectar. Native plants in the
daisy family (Compositae), such as species of Achillea (yarrow), Coreopsis (tick-
seed), Eutrochium (Joe Pye weed), Solidago (goldenrod), and Symphyotrichum
(asters), are especially attractive to them. Parsley family (Apiaceae) members like
fennel and dill will also bring in hardworking beneficials, as will many mint
family (Lamiaceae) representatives such as our native anise hyssop (Agastache
foeniculum). Let beneficial ladybugs, lacewings, hoverflies, tachinid flies, and
parasitic wasps help keep harmful pests to a minimum.TAKING ACTION
If you have a problem you can’t ignore or tolerate, you need to decide what form
of control measures to take. Manual or mechanical control with hands, feet,
strong sprays of water, pruners, and traps should be the primary control. This
manual approach is normally the only one that I take in combating pests in my
gardens and in my clients’ gardens. Insecticidal soaps would be the strongest
control worth considering in the perennial garden, and even these are necessary
only in limited cases. Many of the pests discussed here can be controlled with
such soaps if the gardener feels that it is finally necessary. A mask should be
worn when spraying insecticidal soaps because they can irritate the lining of the
lungs. Certain perennials, such as bleeding heart (dicentra and lamprocapnos)
and ferns such as the Japanese painted fern (Anisocampium niponicum ‘Pictum’),
are sensitive to soap-based products. Test a small area first before spraying an
entire plant or group of plants. Other chemical sprays and dusts, including
naturally derived chemicals such as rotenone or pyrethrin-based products, are
not necessary. Keep in mind that just because a product is naturally derived
doesn’t mean that it is not toxic to one degree or another, either to humans, fish,
birds, pets, or beneficial insects.
It’s worth remembering that phlox and mildew, hosta and slugs, bearded irisLarvae damage and “droppings”
on Artemisia stelleriana ‘Silver
Brocade’.