The picture you had was of maize. Did you mean to ask about Maize?
I can still answer the question about cassava. Sometimes leaves on diffeerent parts of the plant are diseased when the disease is a virus and it is not spread to all leaves equally. Many viruses are injected into the plants by insects and they might feed on one place. Or the virus is present when you planted but it has not spread around equally.
Hope that helps
Posted by: David Hughes
Posted: July 28, 2021