Trichoderma and Cucumber Damping-Off

ISEF Category: Plant Sciences

Subcategory: Pathology  ·  Difficulty: Advanced  ·  Setup: University Lab  ·  Time: Full Year

The Hook

Young seedlings can collapse overnight from damping-off, a disease that hits right when plants are most vulnerable. Tiny fungi can act like bodyguards, or like hidden troublemakers. Your project asks whether a fungus from forest leaf litter can help cucumbers survive that early danger. That gives you a real plant disease problem with clear yes-or-no outcomes.

What Is It?

Endophytes are microbes that live inside plant tissue without causing obvious harm. Think of them like roommates that can be neutral, helpful, or harmful. Trichoderma is a group of fungi known for helping plants in some cases because it can outcompete other fungi, trigger plant defenses, or change the root zone around a seedling.

Damping-off is a common seedling disease. The stem thins near the soil line, then the plant falls over. In simple terms, your project asks whether Trichoderma from forest leaf litter can act like a shield for cucumber seedlings. You are testing a biological control idea, which means using one living thing to reduce damage from another living thing.

Why This Is a Good Topic

This is a strong science fair topic because you can measure a clear outcome, seedling survival or collapse, and compare treated and untreated groups. It connects to real plant disease control, which matters in agriculture, greenhouse production, and home gardening. You can learn fungal culturing, experimental controls, and basic statistics, all from one project. The topic also leaves room for a real discovery if your isolate works better than expected, or if it only helps under certain conditions.

Research Questions

• How does exposure to endophytic Trichoderma from forest leaf litter affect cucumber seedling survival under damping-off pressure?
• What is the effect of Trichoderma-treated rice grains on the rate of seedling collapse compared with untreated controls?
• Does the source of leaf litter change how well the Trichoderma isolate reduces damping-off?
• To what extent does the amount of Trichoderma inoculum change cucumber germination and early survival?
• Which cucumber variety shows the greatest reduction in damping-off after Trichoderma treatment?
• How does the timing of Trichoderma application affect protection against damping-off?

Basic Materials

• Cucumber seeds
• Rice grains or rice-based culture medium
• Zip-top bags
• Sterile petri dishes or clean shallow containers
• Distilled water
• Spray bottle
• Disposable gloves
• Alcohol wipes
• Permanent marker
• Paper towels
• Potting soil or seed-starting mix
• Small planting trays or cups
• Ruler
• Digital balance
• Smartphone camera
• Notebook or data sheet.

Advanced Materials

• Trichoderma isolate from leaf litter
• Autoclave or pressure cooker for sterilizing media
• Laminar flow hood or clean bench
• Petri dishes
• Potato dextrose agar or another fungal medium
• Incubator or temperature-controlled growth area
• Compound microscope
• Hemocytometer or spore-counting chamber
• Hemostatic forceps or sterile tools
• Balance with milligram precision
• Image analysis setup for seedling scoring
• Fungal identification reagents or DNA extraction kit
• PCR access, if you plan to confirm species identity.

Software & Tools

• ImageJ: Measures seedling height, lesion size, and collapse scores from photos.
• Google Sheets: Organizes treatment groups, survival counts, and basic graphs.
• R: Runs survival analysis, t tests, or ANOVA for group comparisons.
• PubMed: Helps you find review articles and primary studies on Trichoderma and damping-off.
• NIH PubChem: Helps you look up any chemical or stain used during fungal identification.

Experiment Steps

1. Define the exact biological question you will test, then pick one cucumber outcome you can score consistently.
2. Plan how you will isolate or source Trichoderma, and decide how you will confirm that your culture is not a mix of different fungi.
3. Design treatment and control groups so you can separate the effect of the fungus from the effect of the rice medium or the soil.
4. Build a scoring system for damping-off, germination, and early growth so your results become numbers, not guesses.
5. Decide how you will randomize trays or seedlings, and plan how many replicates you need for a fair comparison.
6. Choose the statistics you will use before you start, so you know how you will compare survival, growth, and disease severity.

Common Pitfalls

• Using a mixed fungal culture, which makes it impossible to know whether Trichoderma caused the effect.
• Letting the rice medium change the soil conditions, which can mask or fake a disease-control result.
• Scoring damping-off by eye without a fixed rubric, which makes results inconsistent between seedlings and days.
• Packing seedlings too tightly, which increases humidity and creates disease pressure that overwhelms your treatment effect.
• Skipping replication, which leaves you with too few seedlings to tell real protection from random variation.

What Makes This Competitive

A competitive version of this project would go beyond a simple treated-versus-untreated test. You could compare multiple Trichoderma isolates, quantify disease severity with a clear scoring system, and track both survival and growth. Strong projects also control for contamination, randomize plants, and use statistics that fit survival data. If you add species confirmation or compare responses across cucumber varieties, the project starts to look much more like real plant pathology research.

Project Variations

• Test whether Trichoderma helps a different crop, such as beans or tomatoes, under the same damping-off setup.
• Compare forest leaf litter isolates with compost-derived isolates to see whether source habitat changes biocontrol strength.
• Measure whether Trichoderma treatment changes root length, not just seedling survival, after damping-off exposure.

Learn More

• USDA ARS fungal biology resources: Search the USDA Agricultural Research Service site for Trichoderma, fungal biocontrol, and plant disease pages.
• PubMed: Search for review articles on Trichoderma as a biocontrol agent and damping-off in seedlings.
• NCBI Bookshelf: Look for free plant pathology and mycology chapters that explain fungal disease and biocontrol.
• NOAA Climate Data Online: Check local temperature and humidity patterns if you want to connect disease pressure to environment.
• American Phytopathological Society education resources: Read free plant disease primers and pathology background material on the APS website.