Providing adequate drainage primarily helps reduce disease infestations.

• A. Insects
• B. Disease
• C. Thatch
• D. Weeds

Answer: (B)

Providing adequate drainage lowers soil moisture and reduces leaf wetness duration, which are the conditions pathogens need to cause disease. When the root zone stays waterlogged, roots and plants become stressed and more vulnerable to soil-borne diseases; damp conditions also favor fungi and oomycetes that attack foliage and stems. By improving drainage, foliage dries more quickly after rain and standing water is minimized, cutting down the opportunities for disease organisms to thrive. Insects, thatch, and weeds are influenced by moisture in various ways, but drainage targets disease pressure most directly—insects aren’t primarily controlled by drainage, thatch is an organic buildup that drainage doesn’t remove, and weeds depend on many factors beyond soil moisture.