Organic Pesticides for When Natural Methods Fail
GeneralSustainable Farming

Organic Pesticides for When Natural Methods Fail

You’re doing all the right things to keep the bad bugs at bay… planting cosmos and buckwheat flowers in your garden to attract beneficial insects and designing your garden with companion planting methods in mind.

But you STILL have pests.

Sometimes, despite your best efforts to garden without pesticides, the bugs still are munching on your garden, and it may be necessary to bring in a pesticide to protect your garden.

But not all pesticides are equal!

Organic pesticides that do not harm the environment DO exist, and sometimes these are necessary to use as a last defense for your garden. Take a look at a few of these organic pesticide options below.

(A big thank you to David Cook, our Middle TN Ag Extension Agent, for providing us with these great resources during our last Annual Sustainable Farm Conference.)

4 Organic Pesticide Options

FIRST… CHECK THE LABEL.

To determine toxicity levels to humans, you need to first check the “signal word” on the label.

  • CAUTION: Least toxic products.
  • WARNING: More toxic products.
  • DANGER: MOST toxic pesticides.

A note on application: When using chemical or powder treatments on your plants, apply in the early morning or evening. The combo of treatment and hot sun can dry plant leaves out!

1. INSECTICIDAL SOAP:

Insecticidal soaps are derived from potassium salts of fatty acids. They kill the bad bugs by contact—disrupting membranes in the exoskeleton and causing a severe loss of body fluids.

They leave no residual activity behind.

Great for defense against:
(Soft-bodied insects)

  • Aphids
  • Thrips
  • Psyllids
  • Scale crawlers/nymphs
  • Sawfly larvae
  • Plant bugs
  • Mites

2. NEEM OIL:

Neem oil is a vegetable oil extracted from the seeds of the Asian neem tree. The active ingredient, azadirachtin, kills insects by absorbing into their bodies and affecting their hormones and reproductive cycle.

This means that Neem oil does not immediately kill pests. Instead, it tends to kill them as they molt or hatch from eggs, while also disrupting their reproductive cycle.

Neem oil doesn’t leave harmful residues in the environment and insects don’t develop a resistance against it, either.

Great for defense against:
(Chewing insects more than sucking insects and insects that undergo complete metamorphosis)

  • Aphids
  • Thrips
  • Lacebugs
  • Whiteflies
  • Sawflies
  • Japanese beetles
  • Caterpillars
  • Scale
  • Spider mites (and more)

3. ROTENONE:

Rotenone is an alkaloid extracted from the roots of tropical legumes. This can be applied as a dust directly to plants or diluted in water. It remains potent for 2-3 days.

Great for defense against:
(Chewing insects)

  • Aphids
  • Leafhoppers
  • Stink bugs
  • Boxelder bugs
  • Lace bugs
  • Sawfly larvae
  • Caterpillars
  • Japanese beetles
  • Flea beetles
  • Elm leaf beetle larvae
  • Mites (and others)

4. INSECTICIDES AFFECTING WATER BALANCE:

Two insecticides that affect water balance include:

Both these insecticides affect water balance in the bad bugs, thus killing them. While effective when dry, it loses its power when wet, and so has to be reapplied after rain.

Great for defense against:

Read the labels to see a full list of insects these are effective on.