Cicadas are the largest known vectors of Xylella fastidiosa, but there are only two brief published reports of cicadas transmitting this bacterium. One from California using grapevines, and another from Brazil using citrus. Only one of twelve adult Diceroprocta apache collected from grapevines in Coachella Valley, California transmitted X. fastidiosa from grape to grape in lab tests, but the bacterium was detected in one other of the adult cicadas (Krell, R. K. et al. 2007, Am. J. Enology and Viticulture 58: 211-16). Another brief report of cicada transmission of X. fastidiosa was from Brazil (Paiao, F. G. et al. 2002. Fitopatologia Brasileira (suppl.) 27:67).
Cicadas are difficult to test as vectors because they are difficult to capture, and so far impossible to rear in captivity. Furthermore, their behavior in captivity makes manipulating them in transmission trails challenging. Cicadas insert their eggs into woody tissues of twigs or branches in trees or bushes. The nymphs that hatch from the eggs fall to the ground and tunnel down to feed on tree roots. Nymphs can require from 1 to 17 years to develop into adults, depending on the cicada species. The final nymphal stage emerges from underground to molt into an adult, typically on a tree trunk. The newly emerged adults locate mates using their loud air-borne calls. Females use a blade-like appendage to cut a slit for inserting an egg. Like nymphs, adult cicadas feed on xylem sap. Adults can live as long as several months, although most species live only a few weeks.