Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Diagram showing how a leaf is covered by randomly distributed circular lesions. Sleaf, leaf surface; Scovered, leaf surface covered by lesions; σlesion, potential size of a lesion without competition; Slesion, actual size of a lesion with competition.
