The percentage of light used in photosynthesis by a tomato plant decreases when the plant is diseased (Botrytis). It became clear in an experiment at Delphy, using photosynthesis sensors from Sendot, that this can be measured in real time.

In the experiment, two sensors were placed at different ends of the greenhouse. On one side, the tomato plants were affected by Botrytis, while on the other side, the plants were healthy. Although the sensors initially measured the same light utilization on both sides, the light utilization of the infected plants decreased by 10% during the disease, which corresponds to about a 25% reduction in production. This demonstrates the significant impact diseases can have on the most essential processes of a plant. Below you can see the light use efficiency of the plant. The blue represents a healthy plant, and the yellow represents a sick plant.