Coco Academy v1.0 Beta

Plant Defenses: Diagnosis & Management

Understanding common plant problems is crucial for a successful grow. This section helps you identify, prevent, and treat issues, categorized by their severity and commonness.

Integrated Pest Management (IPM): Your First Line of Defense

Quick Overview:

How Much Time: Ongoing (Proactive)

First Thing to Do: Implement daily monitoring and cleanliness routines.

What to Watch For: Any new spots, discoloration, or tiny insects on leaves/stems.

IPM is a holistic strategy to prevent and manage pests with minimal chemical intervention. It's about proactive measures and early detection.

Key Principles:

  • Prevention: Maintain a clean grow space, sterilize equipment, use filtered air intake, and inspect new plants/clones thoroughly.
  • Monitoring: Regularly inspect plants (especially undersides of leaves) for signs of pests. Use yellow sticky traps to catch flying insects early.
  • Identification: Accurate identification is crucial for effective treatment. Use a jeweler's loupe or microscope.
  • Intervention: Start with the least harmful methods.

Consistency in monitoring and cleanliness is your best defense against infestations.

Point of No Return: IPM is about continuous prevention; there's no 'point of no return' for the strategy itself, but failing to implement it can lead to problems becoming untreatable.

Fungus Gnats: The Annoying but Manageable Pest

Quick Overview:

How Much Time: Days to a week

First Thing to Do: Allow top layer of medium to dry out completely.

What to Watch For: Small, dark flying insects near soil; stunted growth in seedlings.

Fungus gnats are small, dark flying insects often seen hovering around the soil surface. Their larvae can cause minor root damage, leading to stunted growth or yellowing, especially in seedlings.

Symptoms:

  • Small, dark flying insects near medium surface.
  • Slowed growth or slight yellowing in young plants.

Causes:

  • Overwatering, consistently wet top layer of medium.
  • High humidity and poor air circulation at the base of plants.

Treatment:

  • Allow topsoil to dry out: This is the most effective first step.
  • Yellow sticky traps: Catch adult gnats.
  • BTI (Bacillus thuringiensis israelensis): Apply as a drench (e.g., Mosquito Bits/Dunks) to kill larvae.
  • Beneficial nematodes: Introduce *Steinernema feltiae* to prey on larvae.
Point of No Return: Fungus gnats are rarely fatal to mature plants. However, severe infestations in seedlings can cause significant stress. The 'point of no return' is generally when root damage is so extensive that the seedling cannot recover, but this is uncommon if addressed promptly.

Spider Mites: The Tiny Destroyers

Quick Overview:

How Much Time: Hours to a day

First Thing to Do: Isolate affected plants and begin physical removal (wiping leaves, water spray).

What to Watch For: Tiny white/yellow dots (stippling) on leaves; fine webbing on undersides.

Spider mites are tiny arachnids that feed on plant sap, causing widespread damage. They reproduce incredibly fast, making them one of the most feared pests.

Symptoms:

  • Tiny white or yellow dots (stippling) on the upper surface of leaves.
  • Fine, silken webbing on the undersides of leaves or between branches in severe infestations.
  • Overall dull, unhealthy appearance of the plant.

Causes:

  • Warm, dry conditions (they thrive in low humidity).
  • Infested new plants or clones introduced without quarantine.

Treatment:

  • Increase Humidity: Temporarily raise RH to deter them.
  • Physical Removal: Wipe leaves, spray with strong water jets.
  • Predatory Mites: Introduce natural predators like *Phytoseiulus persimilis*.
  • Insecticidal Sprays: Insecticidal soap, neem oil, pyrethrins (use with extreme caution, especially in flower). Requires multiple applications.
Point of No Return: Spider mites reproduce exponentially. If webbing is widespread and plants are severely weakened, recovery can be very difficult, especially in flowering. The 'point of no return' is when the infestation is so severe that the plant's ability to photosynthesize is critically compromised.

Powdery Mildew (PM): The White Scourge

Quick Overview:

How Much Time: Hours to a day

First Thing to Do: Isolate affected plants, remove visible spots, and improve airflow/reduce humidity.

What to Watch For: White, powdery spots on leaves, stems, or buds, resembling flour.

Powdery Mildew appears as white, powdery spots on leaves, stems, and eventually buds. It's a fungal disease that can rapidly spread and significantly reduce yield and quality.

Symptoms:

  • Distinct white, powdery patches on leaf surfaces, resembling flour.
  • Can spread to stems and buds, impacting photosynthesis and bud quality.

Causes:

  • High humidity, poor air circulation, and stagnant air.
  • Fluctuating temperatures between day and night.

Treatment:

  • Improve Airflow & Reduce Humidity: Essential preventative and treatment steps.
  • Remove Affected Leaves: Carefully prune and dispose of infected foliage.
  • Fungicidal Sprays: Diluted milk, potassium bicarbonate, or organic fungicides (e.g., neem oil, sulfur burner in veg only).
Point of No Return: PM is highly treatable in the vegetative stage if caught early. In the flowering stage, especially as buds swell, it becomes very difficult to treat without affecting the final product. The 'point of no return' is when PM has colonized a significant portion of the buds.

Nutrient Deficiencies & Excesses: Reading Your Plants

Quick Overview:

How Much Time: Days

First Thing to Do: Check and adjust pH of your nutrient solution and runoff.

What to Watch For: Specific patterns of yellowing, browning, spots, or burnt tips on leaves.

Nutrient imbalances are common and often confused with other issues. Correctly diagnosing them requires understanding which nutrients are mobile vs. immobile in the plant.

Symptoms & Causes:

  • Deficiencies: Yellowing, browning, curling, or spotting of leaves, often in specific patterns (e.g., interveinal chlorosis for Mg on older leaves, general yellowing of new growth for Iron). Caused by insufficient nutrient supply or nutrient lockout due to incorrect pH.
  • Excesses (Nutrient Burn): Dark green leaves, burnt leaf tips ("nutrient burn"), clawing. Caused by too high nutrient concentration.

Treatment:

  • Check & Adjust pH: This is the first step. Incorrect pH is the most common cause of nutrient lockout.
  • Flush the medium: If excess nutrients or lockout is suspected, flush with pH-adjusted plain water.
  • Adjust Nutrient Ratios/Strength: Based on plant stage and observed symptoms.
Point of No Return: Most nutrient issues are fixable if caught early. The 'point of no return' is when a deficiency or excess has caused widespread necrosis (tissue death) across a significant portion of the plant, making recovery impractical.

Environmental Stress: When Conditions Go Wrong

Quick Overview:

How Much Time: Hours to a day

First Thing to Do: Check temperature, humidity, and light distance/intensity.

What to Watch For: Leaves curling (tacoing), drooping, bleaching, or burnt tips.

Plants thrive within optimal environmental ranges. Deviations in temperature, humidity, light intensity, or airflow can lead to significant stress and visible symptoms.

Common Types & Symptoms:

  • Heat Stress: Leaves curl upwards (tacoing), yellowing/browning at edges, stunted growth.
  • Cold Stress: Purpling of stems/leaves, slowed growth, drooping.
  • Light Burn: Bleaching or yellowing of top leaves closest to light, often without other deficiency symptoms.
  • Wind Burn: Clawing, curling, or tearing of leaves from excessive airflow.

Causes:

  • Incorrect temperature/humidity settings.
  • Lights too close or too intense.
  • Fans too strong or directed directly at plants.

Treatment:

  • Adjust temperature, humidity, and light distance/intensity.
  • Ensure proper air circulation without direct blasting.
Point of No Return: Most environmental stress is reversible if corrected quickly. Prolonged severe stress (e.g., extreme heat/cold, severe light burn) can cause permanent damage to affected leaves or even kill the plant. The 'point of no return' is when the plant's metabolic functions are irreversibly compromised.

Bud Rot (Botrytis): The Silent Killer

Quick Overview:

How Much Time: Immediate (Hours)

First Thing to Do: Immediately remove and destroy affected buds. Do NOT try to save them.

What to Watch For: Individual sugar leaves yellowing/browning within a bud, soft/mushy internal bud tissue, gray mold.

Bud rot, caused by the fungus *Botrytis cinerea*, is a devastating disease that attacks dense buds from the inside out. It's often undetectable until it's too late, and it spreads rapidly.

Symptoms:

  • Individual sugar leaves within a bud start to yellow or brown, then pull out easily.
  • Buds become soft, mushy, and discolored (brown/gray) internally.
  • Gray, fuzzy mold may become visible on the surface.

Causes:

  • High humidity (above 60% RH) within the canopy, especially during flowering.
  • Poor air circulation around dense buds.
  • Physical damage to buds (e.g., from handling, pests).

Treatment:

  • Prevention is PARAMOUNT: Maintain low humidity (below 55% in flower), ensure excellent airflow, and prune dense foliage.
  • Immediate Removal: If found, immediately cut out the affected bud section (cut well into healthy tissue below the visible rot) and dispose of it carefully to prevent spore spread.
  • No Cure: Once established, bud rot is generally untreatable. Sprays are ineffective as the rot is internal.
Point of No Return: Bud rot is almost always past the point of no return once symptoms are clearly visible within a bud. The 'point of no return' is essentially the moment the fungus has successfully colonized the internal structure of the bud.

Root Rot: The Hidden Threat

Quick Overview:

How Much Time: Immediate (Hours)

First Thing to Do: Stop watering immediately and inspect roots. Improve drainage and airflow.

What to Watch For: Sudden, unexplained wilting; yellowing/browning leaves; foul odor from root zone; slimy, brown roots.

Root rot is a devastating condition where roots decay due to lack of oxygen, often caused by overwatering or poor drainage. It's hard to spot early and can quickly kill a plant.

Symptoms:

  • Sudden, unexplained wilting or drooping of the entire plant, even if the medium seems wet.
  • Yellowing and browning of leaves, mimicking nutrient deficiencies.
  • Stunted growth, lack of vigor.
  • Foul, stagnant odor from the root zone (in severe cases).
  • Roots appear brown, slimy, or mushy instead of white and firm.

Causes:

  • Consistent overwatering, leading to anaerobic (oxygen-deprived) conditions.
  • Poor drainage in the growing medium or container.
  • High water temperatures in hydroponic systems.

Treatment (Difficult):

  • Immediate Action: Stop watering, improve drainage, and increase air circulation around the roots.
  • Hydrogen Peroxide (H2O2): Diluted solution can provide oxygen and kill anaerobic bacteria.
  • Beneficial Microbes: Introduce beneficial bacteria/fungi (e.g., *Trichoderma*, *Bacillus*) to outcompete pathogens.
  • Repotting: In soil/coco, carefully remove affected roots and repot into fresh, well-draining medium.
Point of No Return: Root rot is very difficult to recover from once it's widespread and severe. The 'point of no return' is typically when a significant portion of the root system has turned brown and mushy, and the plant shows severe, irreversible wilting and collapse.

Viral Infections: The Ultimate Loss

Quick Overview:

How Much Time: Immediate (for prevention of spread)

First Thing to Do: Isolate and immediately remove the infected plant. Sterilize all tools.

What to Watch For: Mosaic patterns on leaves, distorted/crinkled leaves, stunted growth, unusual yellowing/streaking not related to nutrients.

Viral infections (e.g., Tobacco Mosaic Virus - TMV) are systemic and incurable. They can stunt growth, cause deformities, and reduce yields significantly.

Symptoms:

  • Mosaic patterns (light and dark green patches) on leaves.
  • Distorted or crinkled leaves.
  • Stunted growth and overall weak plant vigor.
  • Yellowing, streaking, or necrosis that doesn't resemble nutrient issues.

Causes:

  • Transmitted mechanically (e.g., from contaminated tools, hands, or tobacco products).
  • Can be seed-borne in some cases.

Treatment:

  • No Cure: There is no known treatment for viral infections in cannabis.
  • Immediate Removal: Infected plants should be immediately removed from the grow space and destroyed to prevent spread to healthy plants. Do NOT compost.
  • Sterilization: Thoroughly sterilize all tools, equipment, and surfaces that came into contact with the infected plant.
Point of No Return: Viral infections are inherently untreatable. The 'point of no return' is the moment of infection. Once a plant contracts a virus, it is compromised, and the safest action is immediate removal to protect the rest of your crop.