How does Cucumber mosaic cucumovirus affect plant growth?

Cucumber mosaic cucumovirus (CMV) is known to negatively impact plant growth, primarily by causing symptoms such as mottling, yellowing, and distortion of leaves. When a plant is infected with CMV, it typically exhibits retarded leaf growth, which can lead to a reduction in overall plant vigor. The virus disrupts normal cellular processes and can interfere with photosynthesis, leading to stunted growth and failure to reach typical size or productivity levels.

In contrast, the other potential effects listed—encouraging rapid growth, promoting larger fruit size, and increasing flowering—do not align with the known actions of CMV. Instead, the virus is detrimental to plant health and can cause reduced yields and poor quality in crops such as cucumbers, melons, and other susceptible species. Therefore, the condition described in the correct answer accurately reflects the influence of CMV on plant growth.