Dr. Glenn Wright, an extension specialist in tree fruits at the Yuma Ag Center is the director of the citrus screen house program in Yuma, Arizona. He states that there are about 50 different varieties of citrus and about 70 different trees in this screen house.
It's called a ‘screen house’ because the entire house is surrounded by a special screen to keep insects and disease out. The goal is to grow citrus trees with no disease for their budwood.
"The main insect this particular screen house is trying to keep out is the Asian Citrus Psyllid. The insect carries Citrus Greening Disease which is a devastating disease affecting the Florida citrus industry and is also found in Los Angeles and we don’t want it here," Wright said.
Wright explains what all of these trees are being used for: "For example, if we have a nursery person that wants some budwood from this particular tree so that he or she could make more trees then they will call me and I will clip budwood from this tree. We are assured that budwood from this tree is free of disease.”
A citrus tree is two different trees
When you buy a citrus tree, it's two different trees. The bottom part is called the root stock and it provides the tree with certain disease resistances. You can then graft a seed into the root stock and from there the rest of the tree grows. This helps the tree to start growing fruit in about three years.
Kyma.com also explains how two interesting fruits being grown in the citrus screen house are the Nagomi Cucuiat Kumquat and the Australian Finger Lime.