Natural insecticides that we are discussing here are all of
vegetable origin. There are only 3 main types of natural insecticides
that lave been used commercially. They are listed below.
Rotenone where does it come from ?
Rotenone is produced by 4 types of plants from Leguminosae family of plants.
The main species is Derris ellipitca,
from Africa. The active ingredient acts as a paralyzer inhibiting
oxygen intake of insect cells. It lasts for several days before breaking
down. It is often combined with other insecticides, like Pyrethrum.
How is Rotenone used?
It my be used either in a powder or liquid form. The powder
form is applied by standard dusting applicators. The strength the powder is
usually 0.5 to 1.0 %. The
liquid form, is usually 0.02% by
weight (due to the heavier density of water compared to powders). The liquid is
often mixed with soap, or sulphonated Castor oil. to improve adhesion to the
Bean Beetles, Cage worms, Coddling moths larvae, and Plum Sawfly are all controlled effectively with Rotenone. One of the most common uses is for dusting Sheep dogs and poultry for control of Fleas and Mites. Rotenone has low toxicity for mammals. It is very toxic to cold blooded animals like fish and fogs, so do not use it near farm ponds, or open water.. In Africa it has been used for centuries to kill fish for human consumption.
Pyrethrum , What is it ?
Pyrethrum is produced in the flowers of plants of the
Pyrethrum genus, which is part of the carnation family of plants, It has been
synthesized in the laboratory and is part of many common insect sprays sold for
household use. The man made form is referred to as Pyrethroids the label common
The Pyrethrum acts as a central nervous system paralyzer it works by contact with the insects body, That is why it is effective on soft bodied insects. Insects that have hard shells are more resistant to the effects, as the shell prevents absorption of insecticide.
What insects does Pyrethrum control
The insects that are controlled by Pyrethrum are any soft bodied insect. Cabbage worms Mealy moths, Rose chafer, house flies, stable flies are all killed by contact with the Pyrethrum spray or powder
How is Pyrethrum applied ?
It is available is both powder and liquid forms. The most common form is the containers. The aerosol sprays should be used with caution on sensitive plants. The alcohol or solvent used to dissolve Pyrethrum extract may damage the leaves. The powder and liquid forms may be combined with Rotenone for a wide spectrum natural insecticide, The liquid spay be mixed with potassium soap, for control of spider mites. The important thing to remember is that the undersides of the leaves must be thoroughly wetted with the spray. The spray must contact the insects to kill them. The spray should be applied at least every 3 days, until all the eggs have hatched, and the breeding cycle will then be broken. There are time release aerosol dispensers that will emit a dosage every 15 minutes, automatically. These can be very effective in controlled environment gardens
This plant insecticide can kill insects 2 ways. It is mainly classed as a contact insecticide. It can also kill if the vapor is taken in through the trachea then it can paralyze the central nervous system, It is very effective on soft bodied insects . The list of insects that can be controlled with nicotine include the following, Aphids, Thrips, Red Spider Mites, White Flies, and Coddling moth larvae, It has also been used with success on some types of Saw Flies, and small Beetles (Lepidopterous Larva)
How Is Nicotine used?
The two active forms are Nicotine and Nicotine sulphate. The Nicotine form is usually 95 to 99% pure. The Nicotine sulphate form has 40% active Nicotine content. Either form is applied a liquid spray, using 1 to 3 pounds per 100 gals. water, Soap or other spreading agents are usually mixed in as well. The Nicotine form has also been used as a dust diluted with equal parts of Gypsum, Kaolin or Diatomaceous Earth. Enclosed areas like greenhouses, or grain storage bins have been effectively fumigated by mixing Nicotine with sawdust, and burning small cones, like incense.
CAUTION: Nicotine liquid forms will absorb through the skin . The dust form must not be inhaled (. Use extreme caution)