Many of Texas’ commercial citrus groves are being quarantined to help prevent the spread of a disease that is killing millions of citrus trees around the world.

The state Department of Agriculture recently expanded the citrus quarantine areas to cover Hidalgo and Cameron counties, leaving only small amounts of citrus trees outside of the quarantine zone.

The quarantine allows for strict rules and restrictions about the moving and growing of citrus trees and fruits. The disease was first found in San Juan in 2012 and quickly spread to citrus groves throughout the state of Texas.

The disease is spread between trees by a small bug called a Asian citrus psyllid. These bugs first appeared in Florida in the late 90’s and soon found their way to Texas. The bugs carry a bacteria that is spread through the trees vascular system. An infected tree may stop growing fruit or the fruit it grows may be smaller than normal and fall off of the tree before it is ready.

The disease is not dangerous for humans, but if it continues to spread to more citrus trees, the citrus yield could be less than usual. The bugs that carry the disease can not travel long distances, but they can destroy tree nurseries and stow away in citrus shipments.

Infected trees may not show signs up the disease for months and could spread it to uninfected trees. In 2013 Texas officials passed a law that requires all nurseries to grow new citrus trees indoors to prevent them from being exposed to the psyllids and the disease.

Infected trees are destroyed and new ones are planted in their place. Many nurseries are working to replace the diseased trees’ with healthy ones and are hoping the new trees will not become infected as well.

Image via Wikimedia Commons