Although cultivating marijuana is not difficult, it’s helpful to know about the most prevalent insect and disease issues. Indoor growths occur in a completely controlled environment, so while the danger of pests is lower than in an outside grow, the likelihood of developing difficulties remains a concern and something to monitor. This article will cover how to recognize common cannabis pests and illnesses, the best ways to prevent them (natural and chemical pest and disease management methods), and tips for keeping bugs away from your weed plants to maintain a healthy grow space.
Here are the most common cannabis pest and disease issues you may encounter and ways to address them and their impact.
Cannabis pests may be controlled if detected in time. Pests prefer establishing themselves in your grow room, causing more significant difficulties. Some of the most challenging pests and how to deal with them are detailed below.
Russet mites are the most common cause of crop damage and often live on a plant’s lower branches and the undersides of leaves. As the infection spreads, it moves higher the plant. Because of their minuscule size (0.1mm to 0.2mm), infestations can go undetected until well established. Unfortunately, since russet mites are so small, detecting them without a magnifying glass is impossible. If your cannabis plants show indications of nutrient insufficiency or pH imbalance, check for a russet mite infestation. The indicators are sometimes mistaken for the other.
Spider mites have earned the name “the Borg” as one of the most annoying pests a cannabis producer may encounter. They are arachnids, similar to spiders, and may weave protective webs that cover plants. Spider mites may infest both indoor and outdoor crops and breed rapidly, wreaking havoc on your plants and adversely affecting your entire harvest.
They are resistant to chemical pesticides and may appear to be gone before reappearing with a vengeance. For minor outbreaks, trim damaged plants or entirely remove strongly afflicted plants. You may also add natural predators like ladybugs, lacewings, and predatory mites.
Fungus gnats frequently emerge from your soil after hatching their eggs. Soils containing compost from wood chips appear particularly susceptible to fungus gnats. Some indoor cultivators specifically use wood-free soil preparations to reduce the likelihood of fungus gnats, which may cause substantial damage to root systems and limit development. UVB supplementary lights have a satisfyingly destructive impact on gnats and other insect pests.
Rolls of sticky fly tape are also helpful. Diatomaceous earth forms a barrier, preventing many larvae from emerging from the soil. Many producers encounter fungus gnats during the growing season; while a low-level presence does not guarantee crop failure, it may affect plant health and growth rates.
Once established, broad mites become a serious nuisance. They are so tiny that you may not spot them even with a magnifying glass. The tormented leaves seem twisted, droopy, shiny, blistering, and sickly. Growers frequently mistake the infestation of broad mites for pH, heat stress, or nutritional issues, aggravating the situation.
Specialist chemical sprays (known as miticide sprays, such as ‘Forbid, Avid, and IC’) can be employed; however, they are not always preferred by cannabis farmers. Instead, use neem oil and soap sprays. Mite predators like Neoseiulus are beneficial. Diatomaceous earth is also useful.
Leafhoppers come in a bewildering variety of colors. Their significant problem-causing activity is draining sap from your plants, leaving white, brown, or yellow stains behind. They have wings and six legs and are capable of jumping. They are especially problematic in hot, dry conditions since they require the most moisture or sap.
Specialist insecticidal treatments are available, but few producers prefer to apply pesticides on their buds that they would subsequently vape. Many growers prefer using neem oil and beneficial predators, including ladybirds, lacewings, and parasitic wasps.
Springtails are little hexapods found in soil, leaf litter, and other wet areas. These arthropods, which are only a few millimeters long, can propel themselves into the air using a spring-like appendage called a furcula. Springtails consume decomposing organic materials, fungi, algae, and bacteria found in the soil.
This implies that opportunistic pests can attack delicate marijuana seedlings, especially their sensitive tap roots. Springtail feeding can cause stunted growth, root damage, and lower nutrient uptake, all of which have a detrimental influence on your cannabis plants’ general health. Furthermore, these pests are generally harmless, although their numbers may become a nuisance if left unchecked.
Cannabis illnesses and infections typically cause the most severe problems for your plants. They are generally more difficult to cure than pests. Plant diseases are often classified as either fungal or bacterial. Fungal illnesses are frequently induced by too-wet or humid settings and areas with poor ventilation. Fungal spores float around in the air, seeking a suitable moist location to root, and if the conditions are good, that right wet area may be your plant.
Bacterial infections are generally more subtle and difficult to detect. They can be transmitted by insects, people, rain, and dirty soil or substrate. Bacteria can sometimes enter a plant and leave it relatively unharmed unless it is weakened by external pressures, in this case, they can swiftly destroy the entire cannabis plant. Here are some of the man cannabis diseases you can encounter in your grow:
Bud rot is one of the most devastating illnesses that may affect cannabis plants. It consumes the entire plant without distinguishing between buds, flowers, stalks, and stems. The illness may spread quickly, so you should prevent gray mold from taking root in your plant’s surroundings. Bud rot also loves a cool, moderately humid environment. Thus, maintaining a temperature above 70 degrees Fahrenheit in your grow chamber will assist and regularly monitoring the humidity to ensure it does not become too damp. To develop healthy cannabis plants despite moisture stress, use seeds with good genetics.
They usually do well in tough conditions. You can find numerous grow sets that feature everything you need to grow healthy plants from seed to harvest! Another step is to change clothes or put on protective gear before entering your grow area. The spores can cling to clothes fibers and then be released in the grow chamber if the conditions are favorable.
This is a spore-based fungal disease found in both cannabis indoor and outdoor gardens. The spores are airborne, making them difficult to guard against your plants. It’s also a highly sneaky fungus since the spores may remain latent in the soil until the conditions are ideal for them to begin growing.
Typically, this occurs when the atmosphere is warm and humid. It also happens frequently when cannabis plants are too close together, and there is insufficient ventilation. An overloaded grow area poses an unnecessary risk to your plants. Powdery mildew can also be identified by its white hue covering the marijuana plant’s leaf, inhibiting photosynthesis.
Root rot is a fungus that lives on the plant’s roots developing both inside and when growing marijuana outdoors and in a broad range of substrates, including water in hydroponic systems. Initial signs include plant withering and leaves becoming brown or yellow. Since a variety of issues can cause these indications, it’s necessary to investigate the roots themselves to determine the source. This is because when a cannabis plant becomes infected with pythium, the roots begin to change color, and finally, the outer covering of the roots is removed, revealing a stringy, weak inner core.
You may assist in preventing root rot in your weed plants by thoroughly cleaning the hydroponics system and ensuring that the substrate drains correctly. Remember, preventive care is essential!
Damping off of cannabis seedlings is not a disease; instead, it is a plant’s response to the presence of illness. When you witness damping, the plant appears to be withering; this may mimic overwatering, but it is actually the roots that are creating the problem. Damping off is typically seen in cannabis seedlings. The plant will acquire lesions before it dies totally. Again, preventive treatment is the most effective strategy to address damping off and other fungal disease-related issues.
Cannabis plants usually cannot recover from damping off; thus, it is the grower’s responsibility to prevent it from developing in the first place.
White spots on fan leaves during blooming may be a severe issue for any marijuana producer. Their appearance is mostly caused by both cannabis pests and diseases such as fungus gnats, thrips, spider mites, and powdery mildew. Therefore, every grower must grasp how and why cannabis pests and illnesses affect plants.
Growers can look for white spots on the fan leaves of their plants by paying attention to other visual indicators like yellowing or wilting leaves. In addition, growers can check the plant for any indicators of cannabis pest infestations or diseases. For instance, look for spider webs, droppings, or any signs of mold or mildew growth.
Root-bound cannabis develops when the plant outgrows the container, leaving the roots with little area to increase and resulting in a thick root ball. This is a common issue that can create various cannabis issues for your plants, including stunted growth, nutritional deficits, low yield, and even death. Luckily, root-bound cannabis is easy to avoid with a few simple steps: pick the appropriate container size, consider using cloth pots, and transplant your plant on time. If you still have root-bound cannabis, transplant it to a larger container, being sure to clean the roots and make them less thick throughout the process.
Harvesting a dense canopy of healthy buds entails a lot of troubleshooting, ranging from nutritional deficits to insect infestations. Dry, crunchy leaves are one of the potential issues. This occurs when weed plants lose moisture, coil up, and become brittle and crunchy to the touch.
Several environmental factors contribute to cannabis leaves drying up conditions, including nutritional deficiencies, an abundance of water, and excessive heat. However, do not be alarmed if you observe your fan leaves growing crispy and dried. Take a level-headed approach to the problem: identify it and apply the appropriate solution. If you respond quickly, you’ll be able to save your plants, solve the problem, and improve your gardening skills all at once.
While red or purple stems are occasionally a natural and harmless aspect of cannabis plants, they can also signify issues like environmental stress, nutritional deficits, or insect and disease infestations. It is critical to regularly monitor your plants and check for any further symptoms or indicators of distress. Worry about cannabis purple stems if:
With numerous insect and fungal species eager to infest a cannabis plant, preventative steps are essential. The first step is cannabis strain selection. Choose mold-resistant strains that are good for your environment. Second, consider the surroundings. Reigning in unregulated relative humidity levels, improving ventilation, and generally modifying the local environment will make it unfriendly to unwanted visitors.
In addition, you can use IPM methods. Since cannabis is inhaled and consumed, producers must mitigate the hazards posed by conventional pesticides. It’s why IPM approaches, organic solutions, and biological controls are prioritized. Only after you’ve exhausted all other possibilities should you contemplate using chemical pesticides. If you decide to use allowed cannabis-specific pesticides and fungicides, check with your local legislation.
Organic cannabis pest management employs natural approaches to manage cannabis pests and illnesses. These strategies include cultural controls like correct diet and water management, physical controls like barriers and traps, and biological controls like beneficial insects and fungi. Some of the best organic methods for pest and disease control in marijuana plants are:
Choose a nutrition program and feeding protocol that meets your cannabis plant needs according to its growing situation to limit nutrient imbalances or overload. An effective nutrition management strategy should deliver a balanced supply of critical nutrients throughout the growth cycle, with nutrient ratios varying based on the development stage. Today, you can find numerous sample nutrition regimens and schedules online or design your own based on your experience. The best way to provide your plants with the proper nutrients is to use a high-quality cannabis-specific fertilizer that has the appropriate NPK ratio and micronutrient content for each stage. Furthermore, an excellent general guideline is to start with only slight amounts of cannabis nutrients and boost them gradually as your crop matures.
Some of the essential tools for monitoring and detecting cannabis pests early include:
There are several beneficial insects that can help protect your cannabis plants from common pests, such as:
Cannabis deficiencies affect the plant’s health due to a lack or excess of certain nutrients. Some of the primary cannabis deficiencies are:
Nitrogen toxicity or deficiency
Nitrogen is a macronutrient responsible for photosynthesis, cell and tissue development, and chlorophyll creation. The first indicator of nitrogen deficit in weed plants is slowed growth, which leads to smaller plants and reduced yields. As the deficit advances, the leaves may become yellow, most visible on the bottom ⅔ of the plant. Too little nitrogen causes the bottom cannabis leaves to become light yellow, wither, and finally die. Conversely, too much nitrogen causes leaves to develop a deeper green with downward-facing tips that resemble claws.
Phosphorus is a mobile macronutrient essential for development, photosynthesis, and energy transmission. A phosphorus shortage can be mistaken with copper, nitrogen, or sulfur deficiencies; therefore, be cautious when diagnosing cannabis phosphorus deficiency and other nutritional deficiencies. When identifying this shortage, look for lower or older plant leaves that have become dark green or yellow with brown bronze or somewhat blue splotches.
Calcium is a crucial secondary nutrient for your marijuana plants since it promotes stress tolerance and cell wall strength and controls water absorption and metabolism. A calcium deficit is a relatively common issue in marijuana plants, and it can last for weeks before indicators appear. Some of the main signs of this deficiency are leaf edges turning brown or drying out and plants failing to reach average height.
Copper is a micronutrient that aids in photosynthesis, respiration, and the metabolization of sugars and proteins. It also promotes overall health and normal growth. Copper deficiencies are uncommon, although they can occur at any plant’s life cycle stage, notably during blooming in specific cannabis strains. The leaves at the top of your cannabis plant will darken with blue or purple overtones, while the tips and margins will become bright yellow or white.
Iron is essential for the plant’s general health but can be challenging to detect because it is sometimes mistaken for calcium and magnesium shortages. Since iron is required for chlorophyll formation, the most obvious indicator is yellowing of the leaves. Yellowing is a signal of many plant issues, so keep an eye out for a nearly white yellowing on new or upper leaves, which indicates iron deficiency.
Zinc is utilized in weed plants to manufacture enzymes required for growth and development. This micronutrient is specifically employed to produce enzymes needed for glucose, protein, and chlorophyll formation. When a plant’s zinc levels are low, its development slows and eventually stops. Zinc deficiency signs include slower new growth, shorter distances between nodes, and wrinkled, yellow leaves. New leaves will eventually become yellow and have rust-colored tips.
Silicon is a micronutrient that helps produce stronger stems, withstand droughts, and combat pests and illnesses. It also increases photosynthesis and flower output. Silicon shortage is uncommon; however, it can occur if the plants are cultivated in soil-free media or if the water pH is too high or too low. Silicon deficiency indicators usually include browning and withering of the leaves, weak and brittle stems and branches, stunted growth, and a greater susceptibility to fungal and bacterial diseases.
Keeping your grow space clean and tidy is the most straightforward preventative measure. Clean up and eliminate dead leaves, stems, substrate, and water from the floor and grow area. Pests and illnesses are hunting for homes, so restricting their possibilities is a simple protective approach. Any plant material that has been cut from plants must be removed from the grow room once the chores are completed. Green waste and rubbish should be placed outside the grow chamber to maintain a clean growing environment. Tools should be stored on a workbench or wall, not on the floor. In addition, keep a sterilizing solution of isopropyl alcohol accessible and advise personnel to sanitize instruments before and after use.
Some of the critical steps to implement quarantine measures in cannabis cultivation are:
Incorporating beneficial insects into your growth isn’t the most straightforward process. Remember that while the cannabis pests on your plant require specific conditions, so do the beneficial insects. It is pretty simple for your beneficial insects to die or not fight the pests strong enough, so you’ll have to conduct your research for it to work well. Once you’ve put the beneficial insects in your grow area, you will need to keep an eye on them and be patient when it comes to their growth. The destructive weed insects won’t disappear straight away; it may take a while so they might be fighting it out for days. Furthermore, if you use this technique, you should avoid using insecticides or preventive measures unless the cannabis-beneficial insects are capable of resisting the treatment (which is extremely unlikely).
Proper irrigation and ventilation play a crucial role in the health and vitality of cannabis plants. Here’s why:
Biological pest control is highly successful in controlling cannabis pests, as it eliminates rather than prevents them. When you introduce beneficial insects into your cannabis grow, you must do so after the infestation has begun because they will only survive if they have other insects to feed on. If you have a large number of plants and can afford them, experts recommend introducing new cannabis-beneficial insects every 20 days.
Regular plant inspections are an essential aspect of monitoring for insects and illnesses. Knowing which section of your cannabis plants are prone to insects and diseases might help you prioritize inspections. Diagnosing plant problems is an excellent step-by-step technique for identifying issues and taking orderly notes in a record book. At least once a week, a portion of the plants should be inspected by flipping them over and checking the undersides of the leaves, stems, and roots.
You can also turn your marijuana plants upside down and tap them against a white sheet of paper to remove insects. This will aid in identifying insect hot spots, which may be marked with a flag or tape for closer monitoring or spot treatment. Regular checks of arriving plant materials are also necessary for detecting any issues that may arise with the new plants. If plant issues are not caused by insects or diseases, pH and nutrition testing is highly recommended.
Pesticide applications are a crucial part of cannabis growing. It helps to protect plants against pests and diseases, but it must be done correctly to prevent causing harm to the plants or the environment. It also needs careful planning and execution. Here are a few tips for appropriate pesticide use on cannabis plants:
Crop rotation is the practice of not cultivating the same plants in the same spot in consecutive years. By avoiding growing the same plants in the same location year after year, you may prevent pests and illnesses from building up in the soil. If you relocate the crop, the insect or disease loses its host. For example, soil-borne illnesses can accumulate over years of cultivating the same plants in the same location. Crop rotation may not solve all your disease concerns, but it can make a difference. Crop rotation is used not just to minimize insect issues but also to improve soil health and provide nutrients that various plants require.
Companion planting provides various benefits in an organic approach to cannabis disease control. It encourages biodiversity, attracts beneficial insects, and deters detrimental pests. Furthermore, it can promote soil conditioning, nitrogen fixation, and nutrient absorption. Marigolds placed near cannabis can help repel pests like nematodes and whiteflies. When choosing plants for companion planting, you should also examine their growing tendencies. Plants with comparable heights, space needs, and growth rates will compete less for resources and help each other thrive. Companion planting may improve plant health and create a sustainable landscape with proper design.
Cannabis plants have natural genetic differences that influence their resistance or susceptibility to pests. These genetic changes affect the plant’s capacity to protect itself from pests and illnesses. Some cannabis strains have natural adaptive characteristics, such as dense trichomes, greater resin production, or natural repelling chemicals. These characteristics serve as natural insect deterrents and strengthen the plant’s resilience. Conversely, certain strains may have unique defensive systems that help them to reject, resist, or tolerate pests more successfully than others.
Environmental variables inside each growing area might either hinder or speed up disease transmission. The degree to which you can precisely manage temperature, humidity, light, and airflow determines your ability to influence microbial sporulation, pest mating cycles, and the efficiency of your IPM treatments. The main variables growers need to control inside their growing space are:
Temperature and humidity levels in your growth environment significantly impact insect prevalence and growth. Pests like spider mites have higher metabolic rates in a high-temperature grow environment. This causes them to reproduce more quickly, resulting in rapid population growth. In particular, spider mites have been shown to develop and hatch more frequently in warmer environments, exacerbating infestations. Furthermore, high humidity creates an excellent setting for cannabis pests such as fungus gnats, whose larvae flourish in damp soil. High humidity can also encourage the development of certain diseases, such as mold and mildew, attracting additional pests that feed on these fungi. Conversely, very low humidity can stress cannabis plants, leaving them more vulnerable to infestations as their natural defensive systems deteriorate.
The lighting parameters in a cannabis grow room, including the light intensity and photoperiod, substantially impact insect behavior and lifecycle. Altering the delicate light cycle might upset the breeding cycles of some pests. For example, certain marijuana pests have evolved reproductive systems that need precise light cycles. Disrupting these cycles by varying light duration might interfere with mating and egg-laying habits, lowering their numbers. Furthermore, some pests are more active in specific lighting settings. Certain pests, for example, might prefer lower light intensities and become more frequent if the grow room is not adequately lighted. Optimizing light conditions not only promotes plant development but also aids in pest management.
Adequate air circulation and ventilation in a marijuana grow room are critical for controlling insect infestations. Good air circulation regulates temperature and humidity levels, preventing pest-friendly microclimates from forming. For instance, stagnant air and heated places can hasten bug reproduction and spreading. Furthermore, significant air circulation can physically discourage bugs, making them less likely to settle on plants. Proper ventilation also decreases the possibility of mold and mildew growth, which may attract and support a variety of pests. Maintaining regular fresh air flow can thus be a useful method for reducing the likelihood of bug infestations in grow spaces.
Remo “Urban Remo” Colasanti is world-renowned for his growing skills, and over the past two decades he has helped thousands of people learn how to achieve their garden’s maximum growth potential. He has created a complete system of vitamins, minerals, and extracts – everything your plants need and nothing they don’t. As well as offering Remo Nutrients, Urban Remo also has a whole lot of knowledge in his head that can definitely benefit growers of all levels. Get the chance to learn from the legend himself in the articles below.