Which management practice is effective against Gray mold?

The correct choice emphasizes the importance of sanitation in managing Gray mold, which is caused by the fungus Botrytis cinerea. This pathogen thrives in environments where decaying organic matter, such as old fruit and plant debris, is present. By removing old fruit and plants, you reduce the sources of inoculum that can lead to new infections. Effective management of Gray mold requires disrupting the conditions that favor its growth, and cleaning up the surrounding area eliminates potential sites for the fungus to overwinter or reproduce.

Increasing humidity promotes the conditions that Gray mold prefers, as it thrives in moist environments. Applying high amounts of nitrogen can stimulate plant growth, which in turn might provide more succulent tissues for the pathogen to infect. Frequent irrigation can lead to excess moisture on plant surfaces and in the root zone, creating an environment conducive to Gray mold development. Thus, these practices do not help control the disease and may even exacerbate the problem.