Effects of Temperature on the Flight Activity of <I>Graphocephala atropunctata</I> (Hemiptera: Cicadellidae)

Abstract

Graphocephala atropunctata (Signoret) is the principal vector of Xylella fastidiosa (Wells, Raju, Hung, Weisberg, Mandelco-Paul and Brenner), the bacterium that causes Pierce's disease of grapevine in coastal California. Monitoring the activity of C. atropunctata in the early spring is important for timing insecticide sprays and assessing the potential for disease spread to adjacent vineyards. Trapping studies with yellow sticky traps over 3 yr in Napa Valley, CA, established a significant correlation between early spring trap catch and temperature. Sticky trap catches of G. atropunctata occurred in the springs of 1996-1998 only when temperature was greater than or equal to 14.5 degrees C. In 1997 and 1998, the degree-hours (> 14.5 degrees C) per day from sunrise to sunset during March and April, but not in May, correlated significantly with trap catches. The temperature threshold of 14.5 degrees C in the early spring can be used to improve the timing of insecticidal applications aimed at reducing C. atropunctata populations in vineyards affected by Pierce's disease.

Comparative Dispersal ofHomalodisca coagulataandHomalodisca liturata(Homoptera: Cicadellidae)

“…Based on information from other sharpshooters it is likely that the threshold for ßight is near this temperature. Temperature strongly inßu-enced ßight activity in the blue-green sharpshooter, Graphocephala atropunctata (Signoret) (Feil et al 2000). The derived minimum temperature for ßight was estimated to be 14.5ЊC.…”

Seasonal and Daily Movement of <I>Scaphoideus titanus</I> Ball (Homoptera: Cicadellidae)

“…Movement was higher when daily minimum and maximum temperatures increased, but no thresholds for ßight were detected. Among leafhoppers, a threshold of 14ЊC for take off was detected for G. atropunctata in California (Feil et al 2000). However, G. nigrifrons is more likely to move when average temperatures at dusk are above 18ЊC (Rodriguez et al 1992).…”

“…Studies of daily movement are known for other vectors such as Frankliniella occidentalis (Pergande) (Pearsall 2002), Circulifer hematoceps (Mulsant et Rey) (Kersting and Baspinar 1995), Paraphlesius irroratus (Say) (Larsen and Whalon 1987), Bemisia tabaci (Gennadius) (Blackmer and Byrne 1993), and aphids (Wiktelius 1981). The inßu-ence of temperature on movement behavior and the occurrence of temperature thresholds for the initiation of ßight have been studied for some leafhoppers such as Graphocephala atropunctata (Signoret), a vector of grapevine PierceÕs disease (Feil et al 2000). The objectives of this research were to investigate the seasonal and daily ßight behavior of S. titanus in northern Italy and to determine if and how its ßight activity is inßuenced by temperature and relative humidity.…”

Genetic Structure of Graphocephala atropunctata (Hemiptera: Cicadellidae) Populations Across Its Natural Range in California Reveals Isolation by Distance

“…Much of the research conducted on G. atropunctata regarding life history, disease transmission, and control strategies has focused on populations from northern California (Severin 1949, Purcell 1976, Feil et al 2000 with the assumption that results apply to all populations found throughout California. However, G. atropunctata occupies a northÐsouth latitudinal range of Ϸ1,000 km across California and has limited natural dispersal abilities (Severin 1949).…”