Beneficial Insects manage garden pests
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| Julia Laughlin |
Individuals making the gradual move toward organic gardening
practices can look to Cuba for encouragement. The trade embargo and financial
crisis led Cuba to convert to organic gardening beginning in 1989 since there
was little money for fossil fuels or agricultural chemicals.
Cuba’s food crisis led to restructuring its food growing practices.
Large monocultures were converted to small, local, organic farms that used lower
cost organic inputs.
By 1994, 8,000 farms were being grown in Havana where front lawns,
building lots, school and office gardens were converted to organic food production.
By 1998 those plots grew over half a million tons of fresh, chemical-free, food
for local residents.
Practices they use to keep crops healthy and productive include
inter-planting food crops with plants that attract beneficial insects, growing
compost worms for the worm casting fertilizer they contribute, and leaving crop
compost on the soil after clearing.
According to Oklahoma State University professor emeritus, Julia
Laughlin, most of the insects we do battle with here have zero impact on
humans. In fact, only 15% of insects affect us at all. Of those, 12% are
beneficial and only 3% can be considered pests.
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| Water and pollen providing plants |
Plus, she said, gardeners should learn which insects cause most of
the problems (the 80/20 rule applies) and find out what natural strategies will
keep them away from vulnerable plants.
Important to remember is that most insects are host specific.
Grasshoppers and powdery mildew are not particular but many other bugs and
diseases need certain plants or conditions in order to thrive.
Laughlin thinks the worst pests in her organic growing business
are caused by the aphid/ant mutualism. Here are the steps she
recommended to prevent and combat aphid problems.
Use crop rotation, plant disease resistant varieties, practice
garden sanitation, cover plants with row covers and other insect barriers,
vacuum insect families off of plants, stop tilling, start mulching, time the
crop correctly to have strong plants, never use overhead irrigation, diversify the
crops you plant, use trap cropping and companion planting, recognize and
encourage beneficial insects.
For disease control, Laughlin said gardeners need to understand
the disease triangle: a) host, b) pest, and, c) environment. All three are
necessary for diseases to run rampant through your garden beds.
Gardeners can help themselves by being able to identify these beneficial
insects: Praying mantids, ladybird beetle (adults, eggs and larvae), spined
soldier bug, black and yellow garden spider, crab spider, damsel bug, assassin
bug, wheel bug, big eye bug, syrphid fly and larvae, minute pirate bugs and
green lacewing larvae.
Ground beetle larvae live in the soil and eat slugs, cutworms and
root maggots.
The beneficial predators include: Tachinid fly, Brachonid and
trichorammatid wasps.
Lady beetle larvae and adults eat aphids, scale, thrips, mealybugs
and mites. Most gardeners cannot recognize the lady beetle caterpillars since
they barely resemble the familiar beetles’ adult stage. Green lacewing adults
eat flower nectar but when their young are in the caterpillar stage they are
aphid predators.
We can also plant an insectary strip to increase the population of
good bugs. Include in that planting:
Anise hyssop and zinnias to attract pollinators plus alyssum and
carrot-plant family members such as Queen Anne’s lace, fennel and cilantro to
attract parasitic wasps.
Other plants that attract beneficial insects: Yarrow, all clovers,
vetch, sunflowers, cosmos, all milkweeds, calendula, basil, Mexican sunflower
(Tithonia), asters, catnip, comfrey, coneflowers, evening primrose, mint, and
ironweed.
Laughlin’s radio show, “The Garden Party” is Sat 11:00 on KTOK-1000
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