Natural Pesticide and Insecticides:

As science advance, development of synthetic pesticides and insecticides is occurred. These products have number of harmful side effects and kills harmless and beneficial insect also. Due to this, more emphasis is being given to natural alternatives of these synthetic pesticides that are safe and effective. These natural products have been ignored from long time and exhibit insecticidal / insect repellent effects. Some of them are Neem (Azadirachta indica),  Pyrethrum ( Chrysanthemum), Derris, Cinerariaefolium, Acorus Calamus, Anethum, Nigella sativa, Cyperus rotandus etc.

Few are explaining below:

Pyrethrum:

The insecticidal principles of pyrethrum are located in the oleoresin secretion of floral parts of partially open and closed flowers.  Pyrethrin I and Pyrethrin II are two main active constituents of pyrethrum. It also contains other active constituents such as cinerin I, cinerin II, Jasmoline I and Jasmoline II. All these constituents are chemically esters.

Biologically, pyrethrum is known as Chrysanthemum cinerariaefolium belonging to the family Compositae. The part used is expanded flowerheads and should contain not less than 0.7% of total pyrethrins.

 Pyrethrum is a contact poison and used as an insecticide. It shows rapid toxicity towards different pest but has very low toxicity in mammals.

Neem:

Neem is well known insecticidal. Different parts of Neem contain different type of chemicals.  Main active constituents present in Neem are Sugiol and Nimbiol, beta- sitosterol, stigmasterol, limonoids, maliantroil, nimbidine, nimbendiol, azadiractin, nimaton, quercetin, myrecetin, kaempferol etc.

Leaves:                 Azadirachtin – insect repellant

                                Meliantriol – anti feedant

                                Salanin – anti feedant

Seeds:                  Nimbin – antiviral action

                                Nimbidin – antiviral action

                                Azadirachtin – insect repellant

Flowers:               Nimbosterol, myricitin, Kaempferol – Insecticidal

Fruits:                   Deacetyl azadirachtinol – paralyzes insects swallowing mechanisms.

Bark:                      Nimbin, nimbinin, nimbidin – antiviral

                               Margolone, margolonone – antibacterial

Roots:                   Excellent for reforestation

                              Compounds with antibacterial and antifungal properties.

Neem oil contains 2% of bitters which are sulphur containing compounds nimbin, nimbidin, nimbinin and nimbidol.

Derris:

Main active constituent of Derris is Rotenone which is a contact poison and used in the form of spray for killing vegetable insects during harvesting time. Other chemical constituents present in Derris are tephrosin, toxicarol and degnelin.

Biological, Derris is roots and rhizomes of Derris elliptica Roxb.,  derris malaccensis prain and Lonchocarpus utilis and L. urucu belonging to the family Leguminosae.

Sabadilla:

Sabadilla contains a number of alkaloids like cevadine, veratridine, sabadine, sabadilline etc. Cevedine and veratridine is more potent. It is used in powdered form to kill house flies, thrips and bugs. Sabadilla is dried ripe seeds of Schoenocaulon officinale belonging to the family Liliaceae.

Tobacco:

The tobacco contains pyridine-piperidine type of alkaloids among which nicotine. Other alkaloids are nornicotine and anabasine etc.

Nicotine exerts stimulant effects on heart and nervous system. It is not used medicinally. It is powerful quick acting poison. Even over 40 mg. dose orally may fatal to humans. Nicotine and Tobacco is well known insecticides. Nicotine controls a wide range of insects. It acts as contact poison and effective mainly against soft bodied insects. Nicotine is sprayed On crops in the form of nicotine sulphate. It has advantage over synthetic insecticides because it is safe, well tolerated by warm blood animals, easy to handle, it is volatile in nature and leaves no residue on products.

Other Insecticidal natural products are:

Ryania: Ryanodin is main active constituent used as natural insecticidal.

Nux-Vomica: Strychnine is principle alkaloid which has CNS stimulant activity is used as rodenticide.

Citronella oil: It is volatile oil obtained from Cymbopogon nardus or C. winterianus species belonging to Gramineae family. Geraniol and citronellal are main constituents and used as an insect repellant.