Gardening Advice: Pest-Control Tips

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Photo courtesy Fotolia/Dusan Kostic
Leaffooted bugs and their relatives, including the green stink bug, are hard to ignore during this season. They love developing tomatoes, peppers, eggplants, beans and, especially, Southern peas.

New England/Maritime Canada

The greenhouse is looking empty, the garden, full. Time for
a second planting of lettuce, mesclun and cilantro. By late
June or mid-July, most garden plants will be well
established and looking very lush unless you are plagued
with any one of the “terrible three” — flea beetles,
striped cucumber beetles or squash bugs. Tiny flea beetles
chew pinhead-sized holes in the leaves of greens and
brassicas, turning them to lace. Their larvae attack plant
roots, too. I opt for a fabric row cover over my salad
greens as a physical barrier to protect them, but I use
cottonseedbased dormant oil on brassicas. Used as directed,
this “eco” oil works extremely well to deter flea beetles.
Time usually takes care of striped cucumber beetles. Row
covers or hand picking can protect young plants until they
gain enough size to withstand the damage. Squash bugs are
more of a challenge. To get a jump on our short growing
season, I always set out squash and melon seedlings, rather
than planting seeds. On the day of transplant, these tender
beauties are protected with a roomy bonnet of row cover.
After they send out runners, outgrowing the row cover, they
must be diligently monitored. Squish the bronzegold egg
clusters on the undersides of leaves or smother them with
dormant oil. Later, continue to check under the leaves for
young and mature beetles. As a last resort, the plant-derived insecticide rotenone kills them, but it is very
strong and should be used only as directed, and with great
caution. Rotenone is no longer approved for certified
organic products.

 — Roberta Bailey [FEDCO Seeds, Waterville,
Maine]

Mid-Atlantic

Take a moment in mid-June to sow brassicas for a fall crop.
Plant thickly under a protective fabric row cover, and then
on a wet day in August, move the seedlings out into other
beds. When corn reaches 18 inches in height, try planting
some heat-tolerant lettuce between the rows. Keep watch for
Colorado potato beetles and foil them with hay or straw
mulch, or pick them off the plants. Chickens and runner
ducks are better at this than humans, and enjoy it more.
Lure cucumber beetles away from crops with golden amaranth
(the beetles” favorite); when the amaranth is well
infested, release your fowl to spring the “jaws” of this
trap. Where Mexican bean beetles are a problem, try “Black
Valentine” and “Royalty Purple Pod” beans. These can be
grown, harvested and tilled in just before the beetles
complete a life cycle, and both have proven resistant to
bean mosaic virus. For flavor, yield, and disease and
insect resistance, the old-fashioned yellow crookneck
squash cannot be beat. Try “Thompson” broccoli for a fall
harvest of exquisite disease-and harlequin-bug-resistant
heads. The bottom line, though, is that the best key to
pest prevention I’ve encountered is healthy soil. Watering
plants with compost tea will strongly combat many diseases
and fungi, and, when in doubt, side dress with compost,
too.

 — Cricket Rakita [Southern Exposure Seed Exchange,
Mineral,
Va.]

Southern Interior

Cabbage worms and cabbage loopers can be problems with —
what else? cabbage. They also can attack collards, the
vitamin and mineral-packed favorite Southern side dish.
Both insects are identified easily as small green larvae
eating big holes in your plants. They can be stopped in
their tracks by products containing Bt (Bacillus
thuringiensis), a naturally occurring bacterium that will
not harm humans, wildlife or domestic animals.

Japanese beetles are eating machines, and just a few can
destroy a plant in no time. They aren’t picky about what
they eat, either. Commercially available traps will help,
but make sure you put them far away from the infestation
site, or you may make a bad problem worse by attracting
more beetles to plants already under siege. Aphids can
attack a variety of plants in your garden, including
cucumbers, melons and tomatoes. The tiny green insects
cause the leaves to curl and wilt, and they spread plant
disease as well. Yellow sticky traps are the chemical-free
way to control aphids — they are attracted to the color and
then become stuck in the adhesive “goo.” Insecticidal soaps
also will kill aphids, although several applications may be
needed, and you may have to add a surfactant (spreader) to
make the liquid stick.

 — Lori Hardee and Karen Park Jennings [Park SeedCompany, Greenwood,
S.C.]

Gulf Coast

Now’s the time to plant warm-season crops like okra,
Southern peas, Malabar spinach and sunchokes (Jerusalem
artichokes). Even a late crop of bush beans isn’t out of
the question. Keep up the watering, and mulch everything!
Leaffooted bugs and their relatives, including the green
stink bug, are hard to ignore during this season. They love
developing tomatoes, peppers, eggplants, beans and,
especially, Southern peas. Hand picking may help,
pesticides will work even better, but these bugs keep
coming back. If you’re not too fond of black-eyed peas, you
might plant some off to the edge of the garden and use them
as a trap crop.

Squash vine borers start to lay eggs about the time the
first squash flowers begin to appear. You can watch for the
orange-and-black moths about this time, too — they tend to
come in around dusk; then, swat them with a pingpong
paddle. Or, spray the stems with recommended pesticides.
The best way to deal with pecan scab fungus is by planting
or re-grafting to resistant varieties such as “Caddo,”
“Elliot” or “Forkert.” Plum curculio still will be working
in the nectarines, peaches and plums; remove any small
fruit with a drop of sap protruding as these already have
an egg laid in them.

 — William D. Adams
[Burton,Texas]

Central/Midwest

This is a wonderful time of year, with plants growing
visibly larger every day. Encourage your children to help
out with gardening by planting seeds in shapes instead of
straight rows — our “happy face” onion patch delighted my
daughter last year. Little hands do a fine job weeding, and
curious young eyes help patrol for bugs. One insect we
watch for is the cucumber beetle, which can strip the
leaves off cucurbit seedlings. Some years, we have had to
plant our squash and immediately dust them with a mix of
diatomaceous earth and rotenone. The cucumber beetle not
only eats the plants but also spreads viral diseases, so
it’s important to control them. They can overwinter in corn
stubble, so be sure to do a fall cleanup. If you want to
avoid using pesticides in the garden, learn about insect
life cycles and eating habits; then, plan your garden
accordingly. For example, by seeding carrots after June 15,
we generally can avoid carrot rust fly.

Changing weather can bring problems with plant diseases.
Hot temperatures followed by cool nights and damp weather
spread mildews and early blight. Often, it is too late to
salvage plants after disease sets in, so take preventative
action beforehand: Leave space between plants for air to
circulate and adjust watering practices. If you regularly
notice problems with fungal and viral diseases, look for
disease-tolerant or resistant varieties. It also is
important to rotate your crops each year so that the
soil-borne problems do not overtake your garden.

 — Connie Dam-Byl [William Dam Seeds Ltd., Dundas,
Ontario]

North Central/Rockies

“The problem is the solution,” says Bill Mollison,
co-founder of the Permaculture Movement. The fact that we
perceive a pest or disease as a problem ultimately means we
do not understand enough about our garden and its
ecosystem. Pests give us the opportunity to look further
and understand more. Most pests disappear before much
damage is done, thanks to a host of beneficial helpers. We
help out with daily walks to spot and remove problems while
they are small. Our most effective disease control is
avoidance of top watering. In the drier climates of the
mountainous West, blights, mosaic, molds and scab almost
completely disappear when overhead sprinkling is replaced
with drip or ditch irrigation. We even cured blossomend rot
in our summer squash using this method. If cabbage root
maggots become a problem in extremely wet weather,
carefully mix a spoonful of diatomaceous earth or wood
ashes into the soil, or protect the soil from rain. Plant
radishes as a trap crop, or place tar paper around the base
of plants to deter the flies that lay the rootmaggot eggs.

Cutworms can be discouraged with paper collars at the base
of each pepper plant. Prevent pea-root rot by planting in
well-drained soils and rotating crops frequently. Avoid
planting peas in cold, wet soil in the spring to avoid seed
rot. Many tomato diseases are associated with hot, moist
weather and are not a threat in higher, drier climes
(except in greenhouses). To prevent most problems, use
healthy transplants, fertile soil and plenty of calcium.

 — Bill McDorman [Seeds Trust, High Altitude Gardens,
Hailey,
Idaho]

Pacific Northwest, Part I

Growing a healthy garden with sustainable practices is the
ideal long-term insect control and usually is the most
effective intervention. To attract good bugs to help
prevent pest outbreaks, grow herbs and flowers to provide
sanctuary, pollen and nectar.

Fresh, tender peas are easiest to grow in the Northwest
when using varieties resistant to pea virus and powdery
mildew. Three good examples are “Oregon Trail” shelling
pea, “Oregon Sugar Pod 11” and “Sugar Sprint” snap peas.
Sow through mid-June and again in mid to late July for an
extended fall harvest. Brassicas, members of the cabbage
family, all are susceptible to cabbage root maggot. Young
plants are vulnerable to damage, but with a covering of a
lightweight fabric row cover, you’ll be harvesting perfect
radishes, pak choi and other susceptible favorites. As
plants mature, it’s safe to remove the row cover except in
areas that have had previous heavy infestations.

Reports keep coming in from Northwest gardeners
successfully experimenting with direct-sowing tomatoes in
early June. Try an extra-early variety like “Legend,” don’t
sow too deep and cover the planting space with a hot cap,
clear plastic jug or row cover. The advantages include
gardening ease, no transplant shock and, with “Legend,” you
get valuable late-blight resistance.

 — Rose Marie Nichob McGee [Nichols Garden Nursery,
Albany,
Ore.]

Pacific Northwest, Part II

The focus of June and July is typically on summer crops —
but don’t be deceived. This is the perfect time to start
fall and winter crops, too. As your spring-sown greens
grow, harvest the lower leaves on a regular basis to allow
for multiple pickings. Without a doubt, one pest that tops
the list for most Pacific Northwest gardeners is the
loathed slug. There is nothing worse than planting a
seedling only to have it devoured overnight by these slimy
little hooligans. The best defense I have found is slug
bait containing iron phosphate. Although it is not
certified organic, it is safe to use around pets and
children, and the active ingredient is found naturally in
soil.

If the carrot rust fly mangles your carrot crop, try
growing the resistant yet-sweet-and-tasty “Flyaway” carrot.
Diseases thrive in our moist climate. It is so frustrating
to nurture tomatoes all season long only to have them
destroyed by late blight after the first fall rain. If this
has happened to you, try growing “Legend.” Bred at Oregon
State University, it is the world’s first late-blight
resistant tomato. “Success PM” summer squash is resistant
to powdery mildew, and “Alibi” cucumber resists cucumber
mosaic virus, powdery and downy mildew, and scab. Keep in
mind that one of the best ways to ward off trouble is to
start with a strong, healthy plant. Just like people, the
healthiest plants are the ones best able to combat
diseases.

 — Josh Kirschenbaum [Territorial Seed Company, Cottage
Grove, Ore.]

Southwest

With the arrival of the summer solstice, the Southwest sun
intensifies. Be careful not to over fertilize — too much
nitrogen can attract sucking insects like aphids. Over the
centuries, the “three sisters” of the Southwest — beans,
corn and squash — have nurtured several pests. Squash bugs
(locally called “chinchas”) suck juices from leaves and
fruit. Populations build through the summer with the births
of new generations. Prevent early infestations with a row
cover over your young plants. When flowering begins,
uncover the plants to allow pollination, but treat them
with pepper spray and regularly brush off the clusters of
eggs. Squash vine-borer larvae shut down water uptake,
resulting in wilted plants. Again, prevent this with row
covers. The adult moth usually is gone by the time the
covers must be removed, but check the base of stems for
tiny white eggs throughout July. The Mexican bean beetle
likewise has an early spring cycle and is best avoided by
waiting until mid-June to sow beans. Eggs of a tiny
parasitic wasp (Pediobius foveolatus) are available for
release; encourage adult wasps to remain by interplanting
beans with flowering cilantro. Ear worm damage in sweet
corn can be prevented by applying Bt to the tip of each
ear. I’ve always preferred to exercise some tolerance and
simply cut off any damaged tips. In my experience, raccoons
are more critical to control in corn patches than worms.
Try planting a border of squash plants around your corn as
a prickly barrier to deter the “coons”, or use an electric
fence.

 — Micaela Colley [Seeds of Change, Santa Fe,
N.M.]

Coping with Grasshoppers

In late summer, grasshoppers, katydids and crickets are
staple foods not only of many bird species but of some
larger mammals as well. In the western United States, where
the Big Dry is the seasonal standard, these insects
constitute a major food item at that time of year. They’re
also more prevalent in our gardens then, too.

Only a few of the more than 700 species of “shorthorned
grasshoppers” in the Acrididae family eat cultivated crops;
the others’ appetites call for grasslands. Because the
garden-feeders are highly mobile, both by hopping and
flying, it is not enough to just control the ones inside
the gate; we also have to anticipate the flood of relatives
that will move in when the larger wild habitat is drying
out.

The product Nosema locustae, a biological insecticide, has
been used on “hoppers” with some success. It only kills the
very young instars (stages of growth), so early spring
application is recommended. And it can take up to six weeks
to kill the insects.

Nosema is used mostly on large tracts of range land. No
research has been published reporting on how it works on
areas of less than 10 acres-which would include most
gardens. For small parts of a garden, exclusion with a
fabric row cover is a realistic remedy. Bringing in
domestic birds to feed on the “hoppers” seems to be the
healthiest all-around solution for gardens. Short-term
herding of a small flock of chickens, turkeys, ducks or
guineas inside the garden can put a big dent in the
resident grasshopper crowd. Close attention to the birds’ foraging is required, however, because some will find
garden produce as tasty as the “hoppers”.

If you can let your birds range outside the garden, too,
then you’re more likely to be blessed with an absence of
grasshoppers inside the garden gate. Putting up a temporary
fence about 6 feet outside the permanent garden fence
during the mid to late summer months and letting the
poultry forage in this “moat” for even a few hours a day
will help keep the grasshopper populations down inside the
garden, too.

 — John Stuart


Sources of the Noserna insecticide include Mellinger’s
and Planet Natural. For more on using poultry in your
garden, go to our Web site, and read
Poultry Pest Patrol” and check out “Go Ahead! GetGuineas,” October/ November 2003, in MOTHER’S Archive.