APHIDS
Aphids on underside of
leaf, including nymphs
in various stages of
maturity and white cast skins
(Photo courtesy of Missouri
Botanical Garden PlantFinder)
Aphid damage may appear as pale yellow spots on
leaves, leaves that are curled, puckered, or stunted, and/or distorted
blossoms. Another telltale sign is the sooty black layer they leave behind on
the leaves. Because aphids suck more plant sap than they can use, they exude
a sweet honeydew substance onto leaf surfaces that molds quickly. This soot
can become very unsightly and can interfere with the respiration of the
plant.
Alternative Solutions:
·
Introduce beneficial insects into your garden. Green
lacewings (sometimes called the "aphid lion") are the best
organic defense again aphids. After a few days, the eggs hatch and tiny
larvae emerge with a voracious appetite. There is no better predator known to
consume vast quantities of eggs and the soft bodies of aphids, mealy-bugs,
spider mites, leafhopper nymphs, caterpillar eggs, scales, thrips, and
whiteflies. The ladybug and the praying mantis also have a taste for aphids and
can prove quite effective in an organically managed garden.
·
Use an insecticidal soap, but in moderation, as it will kill beneficial
insects as well as the aphids.
·
Spray your garden with silica Aerogel/Pyrethrin. This product that will
dissolve the cuticle layer on the insect causing it to dehydrate and die.
·
Use Neem Oil.*
Chemical Solutions:
Suggested insecticides for use against aphids
include acephate/fenbutatin-oxide combination (Ortho Systemic Insect Killer), carbaryl (Sevin),
imidicloprid (Merit), tau-fluvalinate (Mavrik), biphenthrin (Talstar),
permethrin (Immunox), and acephate (Orthene).
Because our gardens border neighbors who liberally
use chemicals, organic gardening is not a practical choice. We have found
imidicloprid to be the most effective against aphids in our own gardens.
*A Word (or two or three…) about Neem
Oil
Neem oil is a botanical pesticide made from an extract of the plant Azadirachta indica. When the oil is distilled from the plant's seeds, its concentrated mixture
contains high amounts of the active chemical azadirachtin. It doesn't
strongly affect humans, mammals, or beneficial bugs, and it has been proven
as an effective insecticide and miticide. When sprayed on plants, Neem oil repels harmful insects like white flies, gnats,
aphids, mites, and weevils, as well as reportedly strengthening the crops
against rust, scab, mildew, and blight. Edible crops of vegetables do not get
poisoned when neem oil is used. Additionally, Neem oil makes plants taste bitter, so pests won't eat
them, thereby functioning as a "contact" insecticide. Azadirachtin
also interrupts insects' transitions between different stages of
metamorphosis, such as growing from larvae to pupae. It prevents insects from
developing a hardened exoskeleton. When the chemical gets absorbed through
the roots of plants, it functions as a "systemic insecticide." That
means crops don't need to be constantly re-sprayed. Perhaps the greatest lure
for using neem oil is that it doesn't harm
beneficial insects. Butterflies, earthworms, bees, lacewings are all safe in
your garden.
Sounds too good to be true, doesn't it? Well, for
the Southern gardener, it just might be. Neem oil is just that… an oil. Just
like the dormant oil sprays that burn our plants when it gets too hot, Neem
oil will too. So, about the time that the whiteflies and aphids are most
active, Neem oil will have to find it's way back onto your shelf until the
weather once again drops below 75 or 80 degrees. *Sigh*
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