1 Viewed from Centre of Eternity 615.552.5747 -+- The Merry Pranksters from Menlo Park -+- 10.1990.01.01.24 Marijuana Grower's Handbook - part 24 of 33 by pH Imbalance "Pests" from Marijuana Grower's Handbook [Indoor/Greenhouse Edition] Ed Rosenthal When plants are grown outdoors, pests and insects are ever-present but most of the time they are kept in check by the forces of nature. The wind, rain, changes in temperature, predators and diseases work as a system of checks and balances to keep the populations down despite a phenomenally high theoretical reproductive capacity. Indoors, invading plant pests discover an ideal environment, with few of the hazards they would find outdoors and with an abundance of food. Within a few weeks of invasion the implications of the pests' theoretical multiplication rate are evident and the plants may suffer the ravages of the attack. For this reason, any pest invasion is treated very seriously and quickly. Every insect invasion to the garden has a cause. Most of the time, the pests were carried into the garden by the gardener. Less frequently, pests enter through the windows, cracks, or through the ventilation system. Cautious growers never go into the indoor garden after working outdoors or being in an outdoor garden. They never work on healthy plants after being around or working on infected ones. In some commercial greenhouses, workers change clothing in a dressing room before entering from outside. One grower keeps a plastic dishpan filled with salt water at the entrance to his grow room. As he enters the room he dips the soles of each shoe in the water. This kills any pests which might be riding on the undersides of his shoes. To get a close look at insects, it is a good idea to get a photographer's loop magnifying glass or a portable low-power microscope. Even the most inexpensive ones are adequate. There are six pests that are most likely to attack marijuana indoors: aphids, mealybugs, mites, whiteflies, scale, and caterpillars. A few others sometimes invade greenhouses. These include caterpillars, cutworms, grasshoppers and leafhoppers. APHIDS Aphids are usually found on the undersides of leaves and on stems, though they are sometimes found on the leaf tops. The adults are about 1/32 to 1/16 of an inch long and are oval, almost egg shaped. They have two protrusions from their rear which look like pipes and may or may not have wings. They are usually found in dense colonies with an adult surrounded by a cluster of young. They are usually pale green or yellow, but sometimes are brown, black or red. They molt leaving a white shell. They secrete "honeydew" which is shiny and sticky and is found on infested foliage. Honeydew isa concentrate of the sugars the animal has sucked out of the plant and discarded in its search for protein. Aphids are frequently found together with ants which farm them for their honeydew by carrying them from plant to plant. Infested plants weaken from the insects' constant sucking of sap which they eat by penetrating the deep tissue. Older leaves curl and younger ones grow deformed. Mold sometimes forms on the honeydew. Within weeks the plant may wither. Aphids are carriers of molds and viruses. Indoors, aphids reproduce parthenogenetically; that is, all the insects are females and they can reproduce without being fertilized. They bear live young, which may actually carry embryos of their own before they are born. They can reproduce when they are 6 days old. Luckily, aphids are not difficult to control. Action is taken at the first sign of infection. First, the garden is checked for ants. Any colonies are eliminated using ant bait, ant stakes or boric acid. Then all visible aphids are wiped off the plants using a sponge and soapy water, a soapy water spray or insecticide. A soapy water spray is made by mixing 1.5 tablespoons Ivory Snow Flakes or any other soap without detergent in a gallon of water. Some growers reported success using Dr. Bronner's Eucalyptus or Mint liquid soaps (these are often found in health food stores) at the rate of 1 tablespoon per gallon. This will eliminate most of the pests so that the grower has some breathing space. However, even the most thorough spraying or sponging does not eliminate all of the pests, and since they reproduce parthenogenetically, even one remaining insect can restart the colony. If the plants are not flowering, then spray can be used every 2 or 3 days for several weeks. Thorough sprayings may eventually destroy the colony. They certainly keep it in check. Another convenient spray is available commercially. Pyrethrum is a natural insecticide found in chrysanthemum-family plants. It has not been found harmful to warm-blooded animals but is toxic to aphids, among other insects. Pyrethrum may be purchased as a powder, a liquid concentrate, in a pump or aerosal spray. Usually growers with small gardens choose the aerosols for convenience, while those with large gardens find the concentrates or powders much less expensive. [pH:I wonder what, if anything, adding this to the water for the plant would do to the aphids? If it kills them, this would be a good way to kill them if the plants are flowering.] Some benign insects like to eat aphids and are convenient to use in a greenhouse or grow-room situation. Ladybugs and green lacewings are predators which eat aphids. They can be purchased commercially from insectiaries. These insects also go through a rapid lifecycle and may eat hundreds of aphids as they grow to adults. The insects come with instructions for their use. People are sometimes a little queasy about bringing beneficial insects indoors because they are afraid they will escape into unwanted areas. However, for the most part these insects stay where they belong as long as there is food for them to eat. Adult beneficials sometimes fly directly into metal halide lamps and die instantly. One grower placed a glass reflector around his lamps. The trick is to get the adult beneficials to lay eggs because the predators are most voracious during their immature stages. Given enough food (aphids) this presents no problem. Once the predators become established they keep the pest population at a negligible level, but never eliminate their source of food. MEALYBUGS Mealybugs are light-colored insects which exude a white, waxy cotton-looking substance in which they nestle or which covers their body. They are usually found on the undersides of the leaves and in the joints between the leaves and stems. The adults are from 1/16 to 1/8 inch long. They suck juices from the plant and exude honeydew. Their breeding rate is much slower than many other pests; a generation takes a month or more. A small mealybug infection may be eliminated by using a sponge to wipe the creatures off the plants. They can also be destroyed using a cotton swab dabbed in alcohol, which kills them instantly. More serious infestations may be controlled using a soapy water solution or pyrethrum. As well as eating aphids, green lacewings also eat mealybugs. MITES Mites are the most dangerous pest that can enter a garden. They are not insects, but an arachnid, which is the class of animals that include spiders. Mites are tiny and may not be noticed until they have developed into a serious infestation. There are many species of mites. However the one most likely to attack the garden is the 2 spotted mite, which has two spots on its back which can be seen under a magnifying glass. The first indication that a grower may have mites is seeing pinpoint yellow spots on fan leaves. These spots are located above the points where the mites have pierced the tissue to suck out the plant juices. Mites are very small, measuring only 3-6 thousandths of an inch. They look like small dots colored black, red or brown. Mites' maturity and reproductive rates are affected by temperature. A female lays about 100 eggs during her lifetime, but at 60 degrees she produces 20 offspring, at 70 degrees she and her offspring number 13,000 and at 80 degrees she represents a potential 13,000,000 individuals over a single month. Under ideal conditions mites reproduce a week after hatching. [pH:I have friends who have lost entire plants to these things.] As the mite population rises, the plants weaken. Infested leaves curl under and spider-like webbing is spun which covers the plants and is used by the pests to move from plant to plant. Mites also walk down stems, across medium and across dry space in search of new plants to colonize. [pH:To boldly go where no mite has gone bePO;5bMSB/|.8*zw4r9.Gw-}72rR}`_"|fw%;70n6'0q^$P 8ycZj=lp_X[8$%H$->#o;]KO?GP??{\CSRvf7rnhw}}SC (5~d$a$<