At present, in biological gardening/agriculture, several organic sprays and dusts are being used, as well as Antimicrobials (e.g. germicides, antibiotics, antibacterials, antivirals, antifungals, antiprotozoals and antiparasites) Following article describes these and how to make them.

Wormwood extract made by boiling 100 grams of dried wormwood in 1 liter of water for 20 minutes. Leave for a day. Sift and add soft soap. Thin 1 at 4 before spraying

Chive extract made by putting fresh leaves 2-3 days in water, after which it is sifted and soft soap is added. Thin 1 at 4 before spraying.

Summer tansy dust made by grinding dried herb, and spreading on the ground at density of 1 gram per m². Repels root fly

Stinging nettle extract made by boiling a bucket of stinging nettles for 20-30 minutes in water, sifting it and leaving it to stand for a day. Soft soap is added at a density of 1/100 and the mixture is thinned 1 at 4 before spraying (against aphids, caterpillars) Sometimes brown sugar, brown soap and milk is also added to strengthen the mixture.

Daffodil extract made by boiling 30 grams of daffodils for 20 minutes in 1liter of water. Leave to stand for a day, add 1/100 brown soap and dilute 1 at 4 before spraying (against moulds)

Garlic extract made by soaking mushed garlic in water, adding soft soap at density of 1/100 (against insects)

Rhubarb extract made by boiling 1 kg of leaves in 2 liters of water for 20 mins, adding 1/100 soft soap, sifting it and spraying it (against aphids)

Onion extract made by leaving the leaves for a few days in water, adding 1/100 soft soap, sifting and spraying it (against aphids and caterpillars)

Sambucus extract made by boiling 500 grams of leaves for 30 minutes in 1 liter of water, sifting and thinning it (against aphids and caterpillars)

Tobacco extract: soak old cigar butts, cigarette butts or other tobacco in water, strain, add a little dish soap and spray for aphids, whiteflies and other insects. The active ingredient is nicotine.

Stale beer - it is put outside in a shallow container to attract garden slugs, that then crawl into the container and drown.

For More Information: Organic Agriculture: K-12 Experiments & Background Information

Source: Wikipedia (All text is available under the terms of the GNU Free Documentation License)