Students will research the cause of citrus greening disease and the different methods that are being used to control the disease. Background information is found on p.56-57 and the answer keys are found on p.104-106. This plant lesson and videos illustrate how a disease can spread rapidly through a population using vectors, viral and bacterial reproduction and adaptation, and asymptomatic hosts, much like human diseases. This would be a good introduction lesson to help students understand how COVID-19 spread so rapidly.