Asian citrus psyllid

Description

Diaphorina citri, the Asian citrus psyllid, is a sap-sucking, hemipteran bug in the family Liviidae. It is one of two confirmed vectors of citrus greening disease. It has a wide distribution in southern Asia and has spread to other citrus growing regions. The Asian citrus psyllid originated in Asia but it is now also found in parts of the Middle East, South and Central America, Mexico, and the Caribbean. In the United States, the psyllid was first detected in Florida in 1998 and is now also found in Louisiana, Georgia, Arizona, South Carolina, Texas, and since 2003 in California. In Southern California, the San Joaquin Valley, and Central Coast counties, such as San Luis Obispo, an eradication program has been instituted in an attempt to prevent it from becoming established. In the whole of the United States and its territories, areas where this psyllid are found are under quarantine restrictions. The adult psyllid is about four millimetres long with a fawn and brown mottled body and a light brown head. It is covered with a whitish, waxy secretion which makes it look dusty. The forewings are broadest at the back and have a dark edging around the periphery with a pale gap near the apex. The antennae are pale brown with black tips. These features distinguish it from the superficially similar African citrus psyllid. It typically adopts a head down, tail up posture as it sucks sap. Aphids are often also present on citrus and psyllids can be distinguished from them by being more active, jumping insects, whereas aphids are sedentary. In addition, the antennae of a psyllid has ten segments whereas those of aphids usually have four or six segments. Most aphids have cornicles on the abdomen and psyllids lack these. The psyllid nymph moults five times. It is a yellowish-orange color and has no abdominal spots. The wing pads are prominent, especially in the later instars. The eggs are approximately 0.3 millimeters long, almond-shaped, thicker at the base and tapering toward the top. They are at first a pale color but turn yellow and later orange before they hatch. The long axis is placed vertical to the surface of the leaf. Eggs are laid on the tips of growing shoots, between and near the unfolding leaves. A female may lay up to 800 eggs during her lifetime which may be several months. The whole development cycle takes from two to seven weeks depending on the temperature and the time of year.