Successful cannabis agri-business require healthy plants that are free from pests and diseases. As plants are grown from seed or clone, have a short life cycle, and are often raised in grow rooms rather than greenhouses, it is possible to maintain an almost entirely pest-free growth environment. However, almost always, pests including insects, mites, and pathogens do sometimes find their way into growth facilities. Early recognition, treatment, and continuous monitoring are important to preventing a pest outbreak from getting out of control.
A controlled growth environment with plants that are not excessively stressed is essential for research and healthy yield production of cannabis. Insect pests, pathogens and molds can cause subtle changes in gene expression or plant metabolism that affect research and plant yields.
Therefore, regular inspections for infestations, frequent cleaning of plant growth areas, proper disposal of dead or diseased plant material, and controlled access to the growth rooms will help to make research more reproducible and plant yields more healthy and reliable.
Check out our Cannabis and Hemp growers protocol below for more information.
Plants grow slowly and lack robustness when fungus gnat larvae chew their roots. Seedling and early-rosette-aged plants are the most vulnerable. Small round holes will appear on leaves touching the soil surface where the larvae
have sampled leaf tissue. Seedlings are extremely vulnerable to fungus gnat larvae. With severe infestations, whole seedlings can be devoured overnight. If suspected fungus gnat holes are seen, carefully lift up the leaf and look for whitish translucent larvae with black heads. The larvae will avoid light, and usually respond by burrowing into the soil.
Yellow sticky cards (Whitmire Micro-Gen) hung throughout the growth area will catch adult gnats. These cards work only as a monitoring device and not a control method. Count the number of gnats on each card and keep records as a quantitative measure of the severity of the infestation. Continue monitoring after treating the soil and plants with Rhizosphere AG for the gnats to determine the efficacy of the treatment- spray on the plant and the soil underneath the plant to visible wet.
Cut a small (half-inch) plug of raw potato and place this on the soil surface on random or plants that are suspect. After one day, lift the plug and look for larvae feeding on the potato. This is also a good technique to use for monitoring the success of soil treatment, or as part of a regular inspections of the growth facility. Mark the positions where the potato plugs are and check them every few days. They will need to be replaced as they dry out or become moldy.
Fungus Gnat Treatment
Treatment should be targeted at the larval stage. It difficult to control adults because they hide in places where they are not easily reached by pesticides. Fungus gnat larvae live near the soil surface, so BAC should be applied to the upper inch of the soil. This can be done using a spray nozzle on a coarse setting and spraying the material onto the soil, or by carefully watering the solution onto the growing containers. Eggs and pupae are generally not susceptible to pesticides, so it will be necessary to repeat applications, every 5 to 7 days until the infestation is eliminated.
BAC is not only a good preventive treatment for fresh soil, but also a good pesticide to use on existing fungus gnat infestations. Additionally, application of PreVasive Rhizosphere organic kelp and concentrate manure enzyme and bacteria for soil will increase soil health, create soil fertility and allow the plant to grow faster, stronger and resistant to pests and pathogens.
In addition to B. t. israelensis bio-control, the predatory mite Hypoapsis miles and the predatory nematode Steinernema feltiae can be used on Arabidopsis for biological control of fungus gnats with good results. Both of these organisms need to be incorporated into the soil at planting time. The nematodes are sold under many brand names and, to ensure obtaining viable nematodes, it is best to purchase them through a reputable
biological control supplier. A list of biological control suppliers in North America can be found at the Web Site:www.cdpr.ca.gov/docs/ipminov/ben_supp/contents.htm 
Typically thrip damage will be seen before the insects themselves are detected. Thrips scrape the leaf tissue and then consume the plant juices, which results in silvery-white patches that are usually seen at leaf edges, or near the center of the rosette. Sometimes the white patches will be covered with black dots of thrip frass. Distorted expanding leaves are often caused by thrip damage.
Adult thrips are tiny, slender, and difficult to see. They are 1 to 2 mm long and resemble a small sliver of wood.Larvae of thrips are slightly smaller, but can also be seen. If thrip damage is discovered, blow on the plant gently and then look at the damaged area with a magnifying lens. In response to the CO2 in your breath, the adult and larval thrips are likely to come crawling out from the center of the rosette where they are hiding. Applying the BAC to the plant will be helpful in preventing, repelling and reducing thrip infestations.
Tap plants, especially flowering or aging plants, over a piece of white paper, and thrips will be seen crawling on the paper. Thrips are often found when harvesting plants and seeds.
Thrip Treatment
• Thrips can be suppressed with PreVasive’ Botanical Thyme (BAC) and will not damage leaves. Try minimal concentrations at first dilute ready to use by half for first application.
• Thrips are known to readily develop resistance to several pesticides. For this reason it is important to rotate concentrations from ½ to full every 7 days, also can use 1oz per gallon with BAC on plants.
• Treat all plants in the infested growing area. Adult thrips fly, and can also be transported on clothing
1. Aphids can be found on flower stalks, on young leaves in the rosette center, and on the undersides of leaves.Winged aphids. are highly mobile and typically can be found on the rosette leaves. They are often trapped on the yellow sticky cards used to monitor fungus gnats.
2. A sticky, moist “honey dew” will coat the plant surfaces when aphid infestations are severe.Sometimes this honey dew will turn black with sooty mold. Application of BAC at 1 oz per gallon, is a good prevention tool.
Aphid Treatment Suggestions
As with any chemical treatment of cannabis it is always a good idea to do a test spray on a few plants first. BAC to the plant will be helpful in preventing, repelling and reducing aphid infestations. 
1. All life stages of spider mites are usually found on the undersides of leaves, which makes early detection difficult.Once established, however, they can sometimes be seen crawling across the leaf surface or near the center of the rosette.
2. Mite feeding causes a stippling effect, in which the leaves become covered with white or yellow chlorotic spots.In early infestations, the stippling tends to be more concentrated near the leaf margins.
3. When the infestation becomes severe, spider mites will spin threadlike webbing that covers the inflorescences. Mature flowering plants and senescing plants are especially vulnerable.
Spider Mite Treatment
Only adult spider mites and feeding nymphs are susceptible to PreVasive’ Botanical Thyme BAC. The eggs and dormant nymphs will not be harmed by chemical treatment. Therefore, it is important to plan on multiple applications 5 to 7 days apart. 
Whiteflies will hide underneath your cannabis leaves much as the spider mite and can be just as detrimental. They are teeny tiny and spread diseases as they munch on one plant then move to another. Worse, they traverse afar and spread plant diseases in exponential proportions. To check for whiteflies, all you need do is shake your plant.If you see a swarm of what looks like white dust with wings once disturbed, you have discovered one of the most damaging bugs to your cannabis crop.
Whiteflies feed on the leaves and stems of plants, including cannabis. They excrete honeydew, much as the aphid and also spread diseases. They are one of the most damaging pests to food crops. Since cannabis is consumed or used by humans, it falls under this category when considering harmful pests. Whiteflies are mostly immune to pesticides which makes them a formidable foe. They appear in masses making them hard to control. The best
most effective control method for repelling the whitefly is prevention.
White Fly Prevention
Another natural solution to ridding your cannabis of whiteflies is to apply the BAC on the plants by fogging, spraying or electra-static machine. The BAC is an excellent bug repellant! Apply spray to the plants thoroughly, paying attention to the undersides of the leaves. Spray your plants twice per week until you no longer see them.
DISEASES
In cannabis growth conditions, fungal and bacterial pathogens typically occur in situations where there is high humidity, poor air circulation, or continuously wet soil. Viruses are usually spread either by insects or when plants are propagated from cuttings. However, Erysiphe sp. (powdery mildew) and Botrytis cinerea (gray mold), two fungal pathogens that are familiar in cannabis settings, do occasionally cause spontaneous infections, and are described below.
On the other hand, it is likely that many cases of pathogens infecting cannabis remain unidentified, because it is often easier to dispose of a set of sick-looking plants and start over, rather than trying to identify the potential microbial agent causing the problem. We know from studies of plant–pathogen interactions that cannabis is
susceptible to many pathogens, including a variety of viruses, bacteria, and both necrotrophic and biotrophic fungi. Almost everyone working with cannabis has encountered unexplained symptoms such as wilting, yellowing of the entire plant, chlorosis of leaves, anthocyanin accumulation, or general lack of vigor. Often, this is attributed to a “bad batch of soil,” but it is possible that these sickly plants are infected with an unidentified organisms. PreVasive’ botanical thyme is a antimicrobial cleaner and can prevent many of these unexplained pathogenic issues if utilized with proper cleaning, disinfecting, proper greenhouse methods and PreVasive product system. 
1. White patches of mildew will first become visible at the tips of the upper surfaces of older rosette leaves. When the powdery mildew infection is advanced, cauline leaves, stems, and siliques will also show these patches.
2. Powdery mildew is most easily detected on plants that have reached the large-rosette stage. Plants that are much younger and otherwise appear to be healthy can still have a powdery mildew infection that has not yet reached the reproductive phase and is thus invisible to the naked eye.
Powdery Mildew Treatment
1. Early treatment is important because the airborne spores are easily spread. Avoid spreading powdery mildew by not entering other plant growth areas after exposure to infected plants. 2. When powdery mildew is first discovered, cover the affected plant with BAC at 1 oz per gallon dampened paper towel and clean off the mold.This will reduce the spread of the spores. Spraying plants or moving infected plants drives spores onto
neighboring plants. After cleaning apply the PreVasive’ Botanical thyme to all plants in the room. 