При обрезке центральной точки роста растение ветвится больше

 

Глава 24. Pests

 

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 pest's 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 in- doors: aphids, mealybugs, mites, whiteflies, scale, and caterpillars. A few others sometimes invade greenhouses. These include cater- pillars, cutworms, grasshoppers and leafhoppers.

 

 

По часовой стрелке: тля, белокрылка, червецы, мучнистый червец

 

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 is a 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 1½ 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 I 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 aerosol spray. Usually growers with small gardens choose the aerosols for convenience, while those with large gardens find the concentrates or powders much less expensive. 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 un- wanted 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.

 

 

Тля на листе

 

Mealybugs

 

Mealybugs are light-colored insects which exude a white, waxy cottony-looking substance in which they nestle or which covers their body. They are usually found on the underside of the leaves and in the joints between the leaves and stems. The adults are from 1/16 to 1/6 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 lace- wings also eat mealybugs.

 

Mites

 

Mites are the most damaging 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 pin- point 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. As the mite population rises, the plants weaken. Infested leaves curl under and spider4ike 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. Besides the leaf spots and curling, infested leaves sometimes also bronze and/or develop necrotic brown spots. Most growers do not notice mites until the infestation has been well established and there has been damage to plants. The situation calls for immediate action. First, after careful examination, infested plants are separated from the uninfested ones. Lightly infested plants may be separated from heavily damaged plants. (Physical barriers such as sticky tape are placed around the heavily infested plants, pots or the garden perimeter to prevent migration of mites. Tops are separated so that the mites cannot walk from plant to plant via foliage.) Mites suck juices, so they must evaporate large quantities of water. This is easier for them to do in a dry environment. Humid environments slow down their metabolism, life span, and reproductive rate. Mites may be controlled somewhat by lowering the temperature, thus slowing the insects' life processes considerably. Even if this is done only during the dark cycle, when it is easier to lower temperatures, the progression rate of the infection is slowed significantly. Mites tend to congregate on the leaves rather than the buds, although, as their populations increase, they can start colonizing the buds as well. They can be washed off the leaves using a strong water spray. Growers sometimes use a soapy water spray from a small gauge directional nozzle. Medium pressure can be used. The floor and container surfaces are covered with newspaper or other throwaways so that the mites can be removed by the spray. Buds within 2 weeks of harvest should not be sprayed with soap.

 

Other possible sprays include wetting agents, which interfere with the mites' water-holding ability, flour or starch (½ cup flour, ½ cup milk in a gallon of water) which trap and kill the mites as the mixture dries into a thin film, and an anti-transpiration product, “Wilt- Pruf”® which is sold in many nurseries. It is a chemical which is used to slow down the rate at which plants lose water through their leaves and works by partially coating the leaf's pores. It is frequently used when transplanting and during dry, hot, or sunny periods. Wilt-Pruf also traps mites in its thin film. When these products are used, individual leaves are sprayed using a hand trigger bottle. Some growers “homebrew” a miticide using common spices such as garlic, cayenne pepper, onion, cloves or their combinations soaked in water. Recipes call for either grinding the raw spices or boiling them. One gallon of water is mixed with one or more of the following: ½– 1 ounce garlic, 2–3 ounces of onion, ½ ounce cloves, ½-i ounce cayenne pepper. Before spraying all the plants with a homebrew, try it on a few leaves to make sure that the plants are not adversely affected and the mites are killed. Insectiaries advertise predatory mites for the control of mites. There are several varieties that attack two-spotted mites. Choice of variety of predator mites depends on greenhouse temperature. Some growers have reported great success using these predators, while others report that they have been unsuccessful at getting them to take. When they get established they are effective, but sometimes they seem to disappear in the marijuana garden never to be seen again. Meanwhile, the mites continue to multiply at a geometric rate. On May 23rd, 1986, the New York Times reported on Kelthane, the popular miticide and insecticide. Growers have often reported its effectiveness in eliminating pest problems. However, it turns out that one of the reasons for its effectiveness is that it contains DDT. You say that can't be: DDT was banned from use in 1972. Rohm & Haas Company of Philadelphia, which distributes the product manufactured overseas, has agreed to reduce the level in this product from 2.5% to 1/10th of 1 percent on December 31,1988. Yes, that's right, 1988. The stocks will be in stores well after that date. DDT damages the reproductive systems and nervous systems of mammals. For your own sake, please don't use Keithane or any other miticide-insecticide-containing dicofol. Since mites have a short regeneration cycle, for sprays to be effective they must be used often enough to kill each new generation before it has a chance to reproduce. To prevent buildup of resistance, different sprays are alternated. Several growers have reported eliminating mites using “Holiday Foggers” 3 times a day at S day intervals. Smart growers cover their bodies and wear respirators when working with harmful chemicals. Exposed clothing and underwear is removed immediately after the operation is ended and is washed separately or disposed of. One grower used disposable paper jump suits he found at an army surplus store. Another used clothing one step away from the garbage. After removing clothing, the exposed individual showers well with strong soap. Mites are difficult to eliminate or even control, but it can be done. The means of control depends upon the stage of the plants' life cycle and the degree of infestation. Gardens with a minor infection which are near harvest may be protected simply by lowering the temperature, or by using a quick knockdown spray. Growers sometimes find it more convenient to destroy young plants with a mite infection than to try to combat it. Plants which are nearing the end of the vegetative stage may never flower well if the infection is severe, so that growers try to keep the population down on plants older than 2 months. Growers sometimes start the flowering cycle early when they detect mites. That way temperatures are lowered because of the longer darkness cycle, and the mites do not have as long to build up their population.

 

Whiteflies

 

Whiteflies look like flies except that they are all white. The adults are about 1/16th of an inch long. They can be seen flying off foliage when it is shaken. They lay large white eggs which can be seen on the undersides of the leaves they inhabit. They suck sap from the leaves and leave spots of honeydew. Whiteflies spread black soot, molds and other diseases. Whiteflies undergo four stages of development once they hatch from eggs. Each stage is called an instar. Their life cycle is strictly regulated by temperature. As temperatures increase from 55 to 85 degrees the number of days from egg to adult decreases from 103 to 18 days. However, the adult's life span also decreases. At 55 degrees, the adult lives over 60 days. At 85 degrees it lives fewer than 7 days. At 65 degrees it produces more than 300 eggs over its lifespan, at the rate of more than 8 eggs per day. As the temperature increases, total egg production decreases to less than 30 and the rate of production goes down to fewer than 5 per day. The whitefly population must increase to tremendous numbers before there is any apparent damage to plants directly. However, the honeydew dropped by whiteflies becomes an incubation spot for mold. Whiteflies are easy to control. If there only seem to be a few, they can be pinched off the leaves by hand. Their metabolism is a factor of temperature; at cool temperatures in the low 60's, they are sluggish and easily trapped. They are susceptible to spice sprays and pyrethrum, but the easiest way to deal with them is using Encarsia Formosa, the whitefly parasite. This small non-social wasp is about 1/32nd of an inch long, about the same size as a mite. It lives entirely on whiteflies. The adults eat the eggs and the first and second in- star. They lay their eggs in the third instar. As the wasp embryo develops in the whitefly instar, the egg, which was a pale green or tan, turns black. Encarsia formosa development is also regulated by temperature. At 55 degrees it takes 30 days to reach adulthood, but at 85 degrees it requires only about 10 days. At 65 degrees the adults live about 30 days, but only 8 days at 80 degrees. However the number of eggs laid by females, about 30, does not vary much. They just lay them over a shorter period of time. Insectiaries usually suggest that whitefly parasites be released several times over a 3 week period allowing several generations of whitefly instars to be parasitised, assuring control of the problem quickly. However, experienced growers have found that only 1 release is required, although control takes a while longer. By the third generation the parasites achieve virtual control of the plant eaters and while they do not eliminate them, they keep the whiteflies down to a negligible level and prevent large outbreaks from occurring. Whiteflies are attracted to certain shades of yellow. Nurseries sell cards which are either pre-glued or which can be coated with oil. Any whiteflies which fly to the card are trapped. One grower uses a vacuum cleaner to collect whiteflies from his plants. He says that it is best to do this early in the morning when it is still cool and the insects are sluggish. He says that the vacuum is also effective against aphids.

 

Scale

 

Scale are insects which attack the stems and undersides of leaves. There are two kinds of scale: armored and soft-bodied. Armored scale are 1/6–1/12 inch long and are usually brown, grey or red- dish. They secrete a waxy or cottony substance which shapes a shell to protect their bodies. Soft-bodied scale are usually brown, black or mottled. Their skin is smooth and shiny. Both types are mobile only when they are young. Usually they lose their legs after the first or second moult. The males regain their legs as well as wings at the final moult and spend their short adult life in search of females to inseminate. Scale females can produce up to 5,000 offspring over a lifetime, but they have a relatively slow rate of growth so that it takes a while for them to build a large population. Scale suck sap, leaving little residue. Sometimes immature scale, which are mobile, excrete honeydew. Their saliva may be toxic to the plant. Leaves or branches will turn yellow and die. Scale often look like nodes or blemishes on a stem. They are easily scraped off the plant using fingernails. They do not often attack marijuana; however, some cases have been reported. There are number of effective methods of controlling scale. Since they reproduce slowly, scraping the adults off the leaves and stems may be an effective control. Garlic-cayenne sprays may eliminate them. Finally, there are a number of parasites which at- tack the insects in their immature stages. Predators are often specific to a particular variety of scale, so it's best to send samples of the infection to insectiaries when buying them. Scale can also be killed using a cotton swab dipped in alcohol.

 

Caterpillars

 

Caterpillars are a threat to all gardens. A single moth or butterfly can lay hundreds of eggs, and caterpillars have an enormous appetite. They can devastate a garden of sprouts overnight and can inflict severe damage to mature plants. Species vary as to tastes and habits. Some just munch on the leaves or buds, while others bore into the stems and eat out the plant's stem. The caterpillars which remain on the surface are the easiest to locate and destroy. Once a caterpillar has burrowed into the plant it can be very difficult to find. Sometimes they can be located by looking for the characteristic burrowing hole at its usual location. There are several ways to eliminate caterpillars. Handpicking can be very effective in a small garden. There are several natural insecticides which seem to be harmless to warm-blooded animals and which are lethal to these chewing pests. Bacillus thurengensis (BT) is a bacteria which causes plague in caterpillars. It is available commercially as a powder or spray and can eliminate pests within days. It remains effective until washed away by water. Pyrethrum is also effective against caterpillars. This insecticide is derived from the pyrethrum plant, a relative of the chrysanthemum. When caterpillars have already burrowed into the stem, they must be sought out and destroyed or they will kill the plant. Some growers try to locate the burrow holes and then use a wire or flexible tool to squash the insect in its path. The stems can also be split with a sharp, clean knife or razor and then after the pest is killed the stem is sealed with grafting wax and bound with tape and reinforced with a brace.

 

Глава 25. Цветение

 

Способ, которым конопля определяет время своего цветения был описан выше (см. гл. 3). Она чувствует начало осеннего периода, определяя длительность темного времени суток. Когда ночь становится достаточно длинной – растение зацветает. Этот порог отличается у разных сортов, например Equatorial Sativa начинает цвести при 12-часовом периоде темноты. Большинство разновидностей Indica зацветают при увеличении темного периода с 8 до 12 часов. Мужские растения зацветают раньше женских, и чувствительны к свету только частично. У некоторых разновидностей мужики зацветают после нескольких месяцев роста независимо от режима освещения.

 

Так как женские растения полностью следуют режиму то при использовании искуственного освещения можно заставить растения цвести простым щелчком таймера. После начала цветения конопля быстро вырастает еще на 1–2 фута, поэтому стоит вызывать цветение до того как она станет слишком высокой. Есть несколько слегка различных способов сделать это. Можно при переходе с 18...24-часового светлого периода резко уменьшить его до 12..14 часов. Этот крайне простой способ подвергает растения неоправданному шоку и происходит одно из двух – или они так и не могут до конца от него оправится, или, наоборот, начинают интенсивно расти. Можно наоборот, постепенно снижать длительность светлого периода в течении нескольких недель. После 4–5 недель мощного цветения можно уменьшить «день» на один час, подождать месяц, и опять уменьшить-подождать. Это может быть особенно полезно для некоторых тропических разновидностей, которые не достигают полной зрелости до середины «зимы» (настоящей зимы в тропиках, как известно, нет).