Bitter Orange Trees Taste Yucky To Bugs

The Asian citrus psyllid spreads the bacteria that cause huonglongbing, also known as citrus greening. Now scientists have engineered citrus trees to have a medicinal, sour taste that naturally repels the insects. First confirmed in Florida in 2005, the disease has spread to all citrus growing counties in the state. Citrus growers have faced a costly regime of cutting out dying trees and spraying insecticides to reduce the psyllid populations. To find a solution, scientists turned to a model system: tomatoes. Plant pathology and plant-microbe biology experts identified a handful of naturally occurring insecticides produced by bacteria, fungi and plants known to fend off other types of insects.

Image credit: USDA