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

barkeri, Neoseiulus cucumeris, Iphiseius degenerans, Neoseiulus barkeri, Euseius hibisci), parasitic wasps (Thripobis semiluteus, Ceranisus menes, Goetheana shakespearei), pirate bugs (Orius species), fungus, Verticillium lecani, is effective.
    Sprays: Homemade sprays such as tobacco–nicotine base; commercial pyrethrum, synthetic pyrethrum, insecticidal soap. Apply two to four times at five- to ten-day intervals.
Whiteflies
    Identify: The easiest way to check for the little buggers is to grab a limb and shake it. If there are any whiteflies, they will fly from under leaves. Whiteflies look like a small, white moth about 0.04-inch (1 mm) long. Adult whiteflies have wings. They usually appear near the top of the weakest plant first. They will move downward on the plant or fly off to infest another plant. Eggs are also found on leaf underside, where they are connected with a small hook.
    Damage: Whiteflies, like mites, may cause white speckles, stipples, on the tops of leaves. Loss of chlorophyll production and plant vigor diminishes as infestation progresses.
    Cultural and physical control: Mites are difficult to remove manually because they fly. Adults are attracted to the color yellow. To build a white-fly trap similar to flypaper, cover a bright, yellow object with a sticky substance like Tanglefoot™. Place the traps on the tops of the pots among the plants. Traps work very well. When they are full of insects, toss them out.
    Biological: The wasp, Encarisa formosa, is the most effective whitefly parasite. The small wasps only attack whiteflies, they do not sting people! All toxic sprays must be washed completely off before introducing parasites and predators. Since the Encarsia formosa is a parasite, about 0.125 inch (3 mm) long, smaller than the whitefly, it takes them much longer to control or even keep the whitefly population in check. The parasitic wasp lays an egg in the whitefly larva that later hatches and eats the larva alive, from the inside out–death is slow. If you use them, set them out at the rate of two or more parasites per plant as soon as the first whitefly is detected. Repeat every two to four weeks throughout the life of the plants.
    The fungus Verticillium lecanii AKA Cephalosporium lecanii, trade name Mycatal®, is also very effective in whitefly control.
    Sprays: Easily eradicated with natural sprays. Before spraying, remove any leaves that have been over 50 percent damaged and cure with heat or burn infested foliage. Homemade sprays applied at five- to ten-day intervals work well. Insecticidal soap applied at five- to ten-day intervals. Pyrethrum (aerosol) applied at five- to ten-day intervals.

Whiteflies can be seen in between yellowish aphids. Dark spots are honeydew that has started to mold.
Fungi and Diseases
    Fungi are very primitive plants and do not produce chlorophyll, the substance that gives higher plants their green color. Fungi reproduce by spreading tiny microscopic spores rather than seeds. Countless fungal spores are present in the air at all times. When these microscopic-airborne spores find the proper conditions, they will settle, take hold, and start growing. Some fungi, such as bud-rotting gray mold (Botrytis) are so prolific that they can spread through an entire crop in a matter of days! In fact, one grow room was located near a swamp and Botrytis spores were omnipresent in the environment. Buds and stems contracted gray mold quickly and were often reduced to a wisp-of-powdery-foliage in short order. The grower lost four consecutive crops. Finally, the grower moved to greener pastures and had no trouble with mold. Unsterile, soggysoil, coupled with humid, stagnant air, provides the environment most fungi need to thrive. Although there are many different types of fungi, they are usually prevented with similar methods.

A good vent fan is essential to control humidity indoors.

In general, most fungus does not grow or grows poorly when relative humidity stays between 40 and 50 percent
Prevention
    Prevention is the first step and the true key to fungi control. The section “Setting up the Grow Room” instructs growers to remove anythingcloth curtains, clothes, and other debris-that might attract, harbor, and spread fungi. Cover the carpet with white Visqueen® plastic. If mold should surface on the walls, spray with fungicide. Wash walls with a five percent bleach solution or Pinesol® (made from natural pine oil) and apply paint that contains a fungus-inhibiting