Scientists have developed a simple laboratory method to test how effectively a fungus called Fusarium eumartii infects young tomato plants. The technique involves growing tomato seedlings on special nutrient plates and then exposing them to fungal spores suspended in water, allowing researchers to measure how much damage occurs and how much fungus remains in the plant tissue. This method can be used to quickly test whether different compounds, like chitosan, can prevent fungal infections or help plants defend themselves naturally. The straightforward approach makes it useful for farmers and researchers developing better ways to protect tomato crops from fungal diseases.