Marijuana Horticulture: The Indoor/Outdoor Medical Grower's Bible

active ingredients in natural pyrethrum and kills insects on contact. Pyrethrum is often combined with rotenone or ryania to ensure effectiveness. Aerosol forms contain synergists. (See “Application” below.)
    Controls: A broad-spectrum contact pesticide, pyrethrum kills aphids, whiteflies, spider mites, and insects including beneficials. It is very effective to control flying insects, but they must receive a killing knockdown dose, or they may revive and buzz off.

Pyrethrum
    Caution: Do not mix with sulfur, lime, copper, or soaps. The high pH of these substances render it ineffective. Wash these substances off foliage with plain water (pH below 7) before applying pyrethrum.
    Mixing: Mix in water with a pH below 7 and use a spreader-sticker.
    Application: Spot spray infested plants. Aerosol sprays are most effective especially on spider mites. This can burn foliage–spray is ice-cold when it exits the nozzle-if applied closer than one foot. Aerosol spray contains a synergist, piperonyl butoxide (PBO) or MGK 264. Both are toxic to people. Pyrethrum dissipates within a few hours in the presence of air, HID light, and sunlight. Overcome this limitation by applying just before turning off the lights, the circulation, and vent fans for the night. One manufacturer, Whidmere®, offers encapsulated pyrethrum in aerosol form called Exclude®. As the spray fogs out of the nozzle, a bubble forms around each droplet of pyrethrum mist. The outside coating keeps the pyrethrum intact and extends its life for several days. When a pest prances by touching the bubble, it bursts, releasing the pyrethrum. Liquid and wettable pyrethrum applied with a pump-type sprayer is difficult to apply under leaves where spider mites live.
    Persistence: Effective several hours after application when the lights are on, longer when applied after lights-out and the fan is turned off.
    Forms: Wettable powder, dust, liquid, granular bait, and aerosol.
    Toxicity: Not toxic to animals and humans when eaten, but becomes toxic to people when inhaled. It is toxic to fish and beneficials.
    Safety: Wear a mask and protective clothing when applying sprays or breathing in any form of pyrethrum, especially aerosols. Aerosols contain toxic PBO and MGK 464–possible carcinogens–which are easily inhaled.
Synthetic Pyrethroids
    Ingredients: Synthetic pyrethroids such as permethrin and cypermethrin act as broad-spectrum, Nonselective contact insecticides and miticides. There are more than 30 synthetic pyrethroids available in different formulations. Deltamethrin is available as a sticky paint that is used as a trap when applied to stems and colored objects. Other pyrethroids include Allethrin, cyflutrin, fenpropathin, phenothrin, sumithrin, resmitherin, and tefluthrin.
    Controls: Aphids, whiteflies, thrips, beetles, cockroaches, caterpillars, and spider mites. NOTE: Many insects and mites are resistant to pyrethroids.
    Caution: Nonselective pyrethroids kill all insects and mites including beneficials and bees.
    Mixing: Follow directions on container.
    Application: Follow directions on container. (See “Application” under “Pyrethrum.”)
    Persistence: Breaks down in one to three days. Newer pyrethroids, such as Permethrin, stay active the longest.
    Forms: Powder, liquid, aerosol.
    Toxicity: Toxic to all insects. It is somewhat toxic to mammals.
    Safety: Wear a mask and protective clothing when applying sprays or breathing in any form of pyrethrum, especially aerosols. Aerosols contain toxic PBO and MGK 464-possible carcinogens-which are easily inhaled.
Quassia
    Ingredients: Quassia is made from a subtropical South American tree. Quassia amara, and the tree-of-heaven, Ailanthus altissima.
    Controls: Soft-bodied insects including aphids, leafminers, and some caterpillars.
    Mixing: Available in the form of bark, wood chips, and shavings. Soak 6 ounces (18 cl) of chips per gallon (0.9 L) of water for 24 hours. Afterward, boil for two hours. Add a potassium-based soap to increase effectiveness. Strain and cool before spraying.
    Application: Spray on foliage until saturated.
    Persistence: Two to five days on the surface of plants.
    Forms: Bark, wood chips, and shavings.
    Toxicity: Safe for mammals and (possibly) beneficials.
    Safety: Wear a mask and gloves.
Rotenone
    Ingredients: Rotenone is an extract of roots of several plants including Derris species, Lonchocarpus species, and Tephrosia species. This poison is a Nonselective contact insecticide, stomach poison,