found very helpful this year was to examine all my brassica plants when aphids
first started showing up, and squishing them then. It seemed to curb population
expansion, since the nymphs mature in 1-2 weeks. Prevention is really the key
with any pest/disease, starting with healthy soil. Pests go for the weaker
plants (generally). Pest prevention begins with healthy transplants going into
homemade "soap" sprays won't include that commercial insecticidal soap does is
pyrethrum, a botanical toxin. True insecticidal soap works well in my
experience. Anticipate repeated applications.
from The Organic Gardener's Handbook of Natural Insect and Disease Control,
Barbara Ellis and Fern Bradley, Eds...
vegetable crops and small ornamentals, spray smaller plants frequently with a
strong stream of water to knock aphids off; attract native predators and
parasites by planting pollen and nectar plants; release purchased aphid midges,
lady beetles, lacewings, or parasitic wasps; use homemade garlic, quassia, or
tomato-leaf sprays; spray insecticidal soap; as a last resort, spray infested
plants with neem or pyrethrum. For fruit or shade trees, spray dormant oil to
kill over wintering eggs, and plant flowering groundcovers in home orchards to
attract predators and parasites."
Paco John Verin
City Wide Coordinator - Philadelphia
The Pennsylvania Horticultural Society
100 North 20th Street, 5th
Philadelphia, PA 19103-1495
Phone: 215-988-8885; Fax
We have a small organic community garden plot
in Berkeley, California. Lately we have been experiencing ever-increasing
numbers of aphids which are doing considerable damage to our winter greens.
We've tried spraying them off with a high-pressure nozzle, hand-picking them,
and just recently, applying a mild soap solution. Can anyone recommend any
other successful strategies for dealing with these critters, or ways of
maintaining our plot that will make it less desirable for them to inhabit?
Aphids seem to be attracted to stress of one kind or another. In
community gardens where space is limited, stress is often from
over-crowding. If spacing is the problem, it can often be
overcome by removing/thinning every other plant or even more. Over-watering,
under-watering, and soil deficiency are other stress inducers, but
overcrowding is the most common in a community garden. Remove the stress
and the aphids will usually disappear. When planting winter
greens put yourself in the seed's shoes. How large do you want to be
when you grow up? Give the seed enough space to become all that it can
be and it usually will. When the plant is growing whenever the leaves
touch the neighbor plant's leaves, try removing the neighbor plant.
Roots don't like to intrude on another plants root zone...very stressful for a
Add a good amount of compost and/or a brown/green mulch around all the
plants. The mulch will retain moisture and will feed plants when
decomposed. Add mulch layers regularly.
Wishing you bountiful cabbages,