Pest management strategies for spring
By Urban Harvest
It often comes as a surprise to many people that only 1-2
percent of all insects are considered to be pests of man. Even
those insects considered to be pests serve a role as part of the
food chain; although, several insects such as fire ants,
termites, mosquitoes and fleas often require specialized
management. Beneficial insects are those that help us by
pollinating plants, recycling organic matter, attacking pests
and by performing other such helpful deeds.
The following are a few of the strategies gardeners can
implement to attract and sustain a healthy variety of beneficial
STEP ONE: Take a pass on using harsh, persistent products
in the landscape that kill a broad variety of insects including
beneficial insects. Instead, choose the least-toxic, most
selective and least disruptive products that are available as
needed. These products and the insects and their target pests
include citrus oil (fire ants, scale, chinch bugs), garlic oil
(spider mites, lacebugs), insecticidal soaps (aphids, thrips),
microbes such as Bt or Bti (worms, mosquito larvae), neem oil (lacebugs,
leaf miners), liquid pepper (many insects) and soybean oil
STEP TWO: Gradually change out pest-prone plants with
tougher, better adapted plants that are resistant to pests. Seek
out a multitude of plants that also are known to attract
beneficial insects. Some homeowners often pay for unnecessary,
extra landscape treatment applications due to just a few problem
prone plants that could easily be phased out, reducing the level
of maintenance and expense.
STEP THREE: Observe and identify insects before making
treatments. Since most of the insects in your landscape are
helpful, it pays to identify them before taking action. At
times, it might seem like a specific insect is guilty of being a
pest; however, it often turns out that an insect under suspicion
has moved in to take care of the real culprit. The Texas Bug
Book by Malcolm Beck and Howard Garrett is a helpful
identification guide filled with pest management solutions. Even
when an insect is confirmed to be a pest, it often makes sense
to give nearby beneficial insects some time to move in and help
out. Some of the more common types of beneficials to get
familiar with include: ladybug larvae as well as the adults,
lacewings (not to be confused with lacebugs), assassin bugs,
big-eyed bugs, parasitic and predatory flies (hover, robber,
syrphid, tachanid and), parasitic wasps (braconid, ichneumonid
and trichogramma), spined soldier bugs and ground beetles. It
should be noted that parasitic wasps do not sting people.
STEP FOUR: Provide water sources for beneficials to help
them endure dry stretches. Ponds, bird baths and other water
elements work well. Landscape beds enriched with compost and
topped off with a layer of mulch and lawns insulated with
recycled clippings often retain enough moisture to sustain
beneficials through dry periods. Mosquito dunks can be added to
bird baths, ponds or other elements to kill mosquito larvae,
while not harming beneficials. The naturally occurring bacterial
strain Bacillus thuringiensis israelensis (Bti) is the active
ingredient in Mosquito Dunks (donuts).
STEP FIVE: Recycle organic matter such as fallen leaves,
and use the leaves as mulch to help provide shelter for the
extremes of summer and winter. The larval stages of many types
of beneficial insects such as ground beetles (they eat slugs)
need organic matter as a food source.
STEP SIX: Plant your own "field (landscape) of dreams."
It does sound corny, but in the case of attracting beneficial
insects to your landscape, "if you build it" (nectar producing
plantings), "they (the beneficials) will come." That's right, in
most cases you do not have to buy beneficial insects such as
ladybugs. However, in some cases (especially commercial growing
operations), it can make sense to introduce (purchase)
beneficials such as lacewings that are more likely to do the job
and stick around.
Most adult stages of beneficial insects survive by feeding on
nectar. Nectar producing plants to consider adding this spring
include: brown-eyed Susan; fennel; heirloom pentas, lantana;
Mexican hat, Mexican milkweed, native asters (by seed), passion
vine, sunflowers, tropical sage (scarlet sage), verbena, wild
ageratum (by seed), winecup, and yarrow.
Consider adding plants to ponds or bog gardens such as pickerel
rush, arrow-head, tuckahoe and lizardtail to attract dragonflies
and damselflies, both of which are voracious predators of
mosquito larvae and adults.
Mexican milkweed is a "must add" element due to its value as a
beneficial insectaries plant. This sun-loving plant is not only
a host plant for the Monarch butterfly, but it is also helpful
as a trap plant. Mexican milkweeds regularly harbor a small
population of aphids on the upper portions of their stems. The
plants tolerate the aphids very well, and some aphids will be
present on the plants year-round, providing a steady, ongoing
source of food for beneficial insects. With a steady food
supply, a wide variety of beneficial insects including assassin
bugs, ladybugs, lacewings, hover flies and others will be more
likely to stay around all year. For those of you who have a
crape myrtle or two or bush beans, Mexican milkweeds will help
keep aphids from posing as much of a problem for those plants.
And finally, many gardeners end up with a new source of
entertainment as they discover, observe and learn more about the
insects that visit their landscapes.
This column is produced by Urban Harvest. Learn about
gardening classes, community gardens and orchards, farmers'
markets, and more at
article was written by Mark Bowen who is a knowledgeable
resource in native plants, food access issues, organic
gardening, co-author of “Habitat Gardening for Houston” and
former executive director of Urban Harvest.