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The glassy-winged sharpshooter, Homalodisca coagulata (Say). Photo by Jack Kelley Clark, courtesy UC Statewide IPM Program. 

The glassy-winged sharpshooter, Homalodisca coagulata (Say). Photo by Jack Kelley Clark, courtesy UC Statewide IPM Program. 

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The glassy-winged sharpshooter, Homalodisca coagulata (Say), is a major pest of agricultural, ornamental, and native plants. It is native to the southeastern United States and northeastern Mexico. Homalodisca coagulata was first recorded in Tahiti (French Polynesia) in 1999. It reproduced and spread rapidly in French Polynesia and is currently foun...

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... glassy-winged sharpshooter, Homalodisca coagulata (Say) ( Figure 1), is native to the southeastern United States and northeastern Mexico (Triapitsyn and Phillips 2000). In the late 1980s this insect invaded California in the United States (Sorensen and Gill 1996), and by the mid-1990s populations in Southern California had become widespread and extremely pestiferous in agricultural and urban areas (Pilkington et al. 2005). Homalodisca coagulata exhibits high invasion potential, having become successfully established in the Pacific islands: French Polynesia in 1999 (Secretariat of the Pacific Community 2002), Hawai‘i in 2004 (Hoover 2004), and Easter Island in 2005 (Sandra Ide, 2005, pers. comm.). Climate match modeling suggests that many other areas of the world are highly vulnerable to invasion by H. coagulata (Hoddle 2004). Homalodisca coagulata is xylophagous. Xy- lem fluids lack defensive secondary chemicals that require detoxification, and this may ac- count for the extreme polyphagy of this insect (Raven 1983). Due to the low nutri- tional value of xylem, xylophages need to in- gest large quantities of fluid. Consequently, H. coagulata can consume up to 100 times its body weight per day (Brodbeck et al. 1993), and copious amounts of watery excreta are produced and continuously discharged as a result of prolific feeding. Females lay eggs within plant tissue on the underside of leaves. Adults and the five nymphal instars can feed on more than 150 plant species in 34 plant families (Hoddle et al. 2003). In its home range and invaded areas, the major threat posed by H. coagulata to agricultural crops and ornamental and native plants is its ability to vector a xylem-dwelling bacterium, Xylella fastidiosa (Wells et al. 1987), which causes a variety of lethal scorchlike diseases in susceptible hosts (Hopkins and Purcell 2002). In French Polynesia, H. coagulata was first reported in July 1999 on the windward island of Tahiti in the Society Islands archipelago (Secretariat of the Pacific Community 2002). Nymphs and adults were found on one speci- men of Lagestroemia speciosa in a private gar- den in the town of Arue, part of the metropolitan area of Papeete in the north of Tahiti. In an attempt to prevent the spread of this pest, the infested tree was treated with broad-spectrum insecticides before it was cut down and destroyed. Homalodisca coagulata was not observed again in Tahiti until July– August 2001, when large populations were detected on numerous plant species in many different places in the metropolitan area of Papeete. The French Polynesian Plant Protection Department was alerted after numerous public complaints about the large quantities of H. coagulata excreta raining from infested trees. Two possibilities exist for the discovery of this later infestation: (1) H. coagulata was not eradicated in July 1999, or (2) subsequent accidental introductions led to the 2001 outbreak. These hypotheses are not mutually exclusive and are difficult to distinguish without detailed genetic studies (Davies et al. 1999 a,b ). It appears most likely that a permanent population of H. coagulata was established in Tahiti in 1999 or earlier, probably due to infested ornamental plants bearing egg masses (this life stage is relatively immune to insecticide applications) imported from California. Since it became established, H. coagulata has spread rapidly within the Society Islands. In 2001 it was found in Raiatea (Leeward Islands), in 2002 in Moorea, and small incipient populations of H. coagulata were discovered in the Leeward Islands of Huahine and Bora Bora in 2003 and in Tahaa and Maupiti in 2005. At the end of 2004 and the beginning of 2005, populations of H. coagulata were discovered outside the Society Islands in two other archipelagos of French Polynesia substantially distant from Tahiti: the Australs, where two islands were infested (Rurutu and Tubuai) ( January 2005, French Polynesian Department of Agriculture observations), and the Marquesas, where one island was found infested (Nuku Hiva) (November 2004, French Polynesian Department of Agriculture observations). On these recently infested islands, numerous nymphs and adults were found; therefore, the dates mentioned do not correspond to the arrival of H. coagulata but likely indicate that this pest had been present for several weeks or months and was noticed only after populations reached high densities. It is possible that H. coagulata is present on other islands in French Polynesia and has not yet been discovered. It is currently unknown if H. coagulata has invaded the Tuamotu group. Continued spread of H. coagulata in French Polynesia is probably due to insuffi- cient quarantine measures to prevent un- wanted movement between infested and uninfested islands. Movement of plant material is not controlled between islands within the Windward Islands of Tahiti and its close island neighbor Moorea, which explains why H. coagulata spread quickly from Tahiti to Moorea. Plants that are shipped from Tahiti to other more ...

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... Xylella fastidiosa can be transmitted without strain specificity by many vector species, primarily sharpshooter leafhoppers (Cicadellidae: Cicadellinae) and spittlebugs (Aphrophroidae) (Almeida 2016b). Xylella fastidiosa can arrive inside invasive vectors like the glassy-winged sharpshooter, Homalodisca vitripennis (Germar), as occurred in Hawaii and French Polynesia (Grandgirard et al. 2006, Mizell et al. 2008). More commonly, however, X. fastidiosa invades via contaminated host plant material; subsequently, the bacterium co-opts competent native vectors in the invasion area. ...
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... This species is native to southeastern USA (Young, 1958;Turner and Pollard, 1959) and colonised California in the 1990's (Phillips et al., 2001) and the French Polynesia in 1999 (CABI, 2018). The expansion in the geographical range of H. vitripennis has not been associated with the spread of X. fastidiosa (Sorensen and Gill, 1996;Grandgirard et al., 2006): It is generally considered that the main long distance dispersal pathway for the pathogen is the movement of infected, and potentially asymptomatic, plant material from areas where the pathogen occurs (EFSA PLH Panel, 2015Almeida and Nunney, 2016); however, infective insect vectors as hitchhikers could also play a role (EFSA PLH Panel, 2015. ...
... For such a mobile group of insects, hitchhiking could also provide a pathway for entry (EFSA PLH Panel, 2015). However, as stated earlier, there is evidence that the expansion in the geographical range of the only invasive vector of Xylella spp., H. vitripennis, has not been associated with the spread of the bacterium (Sorensen and Gill, 1996;Grandgirard et al., 2006). ...
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... In the United States, one of the principal vectors of X. fastidiosa is the glassy-winged sharpshooter (Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae)). The glassy-winged sharpshooter is native to the southeastern United States and northeastern Mexico, and in the last 40 years has expanded its range to include the western United States, Hawaii, and French Polynesia (Sorensen and Gill 1996, Grandgirard et al. 2006, Stenger et al. 2010 The glassy-winged sharpshooter is polyphagous and consumes xylem sap from a wide range of plant species (Hoddle et al. 2003). Females emerge as adults without mature eggs (Sisterson 2008), and adult feeding is required to produce mature eggs (Sisterson 2012). ...
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... Chemical and biological control of H. vitripennis has been tested using a variety of agents, including pesticides, predation, and parasitic wasps (Triapitsyn et al., 1998;Bethke et al., 2001;Grandgirard et al., 2008;Guiterrez et al., 2011), and efforts have even included attempts to inoculate the insect with benign strains of X. fastidiosa (Hopkins, 2005). The economic burden of these efforts is significant, in California alone the annual cost of monitoring, control and research is approximately US$50 million per year, and despite this effort H. vitripennis causes direct loses of an estimated US$60 million per year (Alston et al., 2013;Tumber et al., 2014) (Grandgirard et al., 2006;Gunawardana et al., 2008;Petit et al., 2008). In warmer climates, H. vitripennis flourishes, displaying an increased rate of feeding (Johnson et al., 2006) and mating more frequently (Blua et al., 1999;Grandgirard et al., 2006), making it capable of achieving a much greater population density than that observed in California Wistrom et al., 2010). ...
... The economic burden of these efforts is significant, in California alone the annual cost of monitoring, control and research is approximately US$50 million per year, and despite this effort H. vitripennis causes direct loses of an estimated US$60 million per year (Alston et al., 2013;Tumber et al., 2014) (Grandgirard et al., 2006;Gunawardana et al., 2008;Petit et al., 2008). In warmer climates, H. vitripennis flourishes, displaying an increased rate of feeding (Johnson et al., 2006) and mating more frequently (Blua et al., 1999;Grandgirard et al., 2006), making it capable of achieving a much greater population density than that observed in California Wistrom et al., 2010). Environmental modelling has suggested that H. vitripennis is capable of surviving in any climate that supports grape production, including that of Australasia (Hoddle, 2004;Rathé et al., 2012). ...
... Environmental modelling has suggested that H. vitripennis is capable of surviving in any climate that supports grape production, including that of Australasia (Hoddle, 2004;Rathé et al., 2012). It has been speculated that the accidental transport of plants carrying H. vitripennis eggs was the original source of its introduction into California, French Polynesia, and Rarotonga (Sorensen & Gill, 1996;Grandgirard et al., 2006;Gunawardana et al., 2008;Petit et al., 2008), and this mode of spread is considered the likeliest source of an incursion into Australasia (Grandgirard et al., 2006;Rathé et al., 2012). ...
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... To our knowledge, there is only one example of an X. fastidiosa vector being considered invasive, spreading over vast geographical distances and reaching large populations at various environmental conditions (Grandgirard et al. 2006;Petit et al. 2008). Homalodisca vitripennis (Cicadellidae, Cicadellinae) is native to the southeastern United States (Turner and Pollard 1959;Young 1958) and invaded California sometime in the late 1980s (Stenger et al. 2010) but was not detected until 1990 (Sorensen and Gill 1996). ...
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... However, a single stopover can extend this flight time to 17 or more hours (Webjet 2014). Dead H. vitripennis adults have been found in aircraft in Cairns, Australia, that have flown from Tahiti and unofficial reports suggest H. vitripennis adults have survived the flight from Tahiti to Japan (Grandgirard et al. 2006). Studies have indicated that H. vitripennis may be able to survive much longer than was previously thought (over 24 h) without a food source (Phillips 2004;Son et al. 2009), although exactly how long appears to be dependent on temperature. ...
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... During the past 120 years, more than 5000 biological introductions of approximately 2000 different species of natural enemies of arthropods have been carried out to control the population density of pest species (i.e., classical biological control) (Roderick and Navajas 2003; van Lenteren et al. 2006a; Cock et al. 2010). However, only 16% of all those introductions have established and resulted in the successful control of the target pest (Caltagirone and Doutt 1989; Bellows 2001; Roderick and Navajas 2003; Grandgirard et al. 2006 ). This low success rate of man-made introductions of biological controllers has been explained, in part, as the result of (i) the introduction of agents poorly adapted to local environmental conditions, (ii) the ...
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... Twice yearly oviposition has been reported in California (Blua et al. 1999), with a partial third egg-laying period possible in some regions (Hummel et al. 2006). Six to eight overlapping generations have been estimated to occur per year in Tahiti (Grandgirard et al. 2006), and a single mating is sufficient to fertilise an entire complement of eggs that can then be oviposited throughout an individual's lifetime (Sisterson 2008). ...
... Symptomless host plant material from the United States, Central America, South America (which has the strain of X. fastidiosa causing citrus variegated chlorosis) (Hopkins & Purcell 2002;Chung & Brlansky 2005), Taiwan and Kosovo may also contain the pathogen. Inadvertent introduction of X. fastidiosa into Australia may have already occurred and there is a possibility that the pathogen is harboured in symptomless hosts that are currently present in Australia (Hoddle 2004 (Grandgirard et al. 2006). Dead H. vitripennis adults have been intercepted in planes in Cairns, Australia that had flown from Tahiti via New Caledonia (Grandgirard et al. 2006), illustrating that unintentional transport to Australia may be possible. ...
... Inadvertent introduction of X. fastidiosa into Australia may have already occurred and there is a possibility that the pathogen is harboured in symptomless hosts that are currently present in Australia (Hoddle 2004 (Grandgirard et al. 2006). Dead H. vitripennis adults have been intercepted in planes in Cairns, Australia that had flown from Tahiti via New Caledonia (Grandgirard et al. 2006), illustrating that unintentional transport to Australia may be possible. Almost 100 flights a day arrive in Sydney from areas infested with H. vitripennis indicating a high number of opportunities for this pest and X. fastidiosa to arrive each day, in just one Australian city that has a suitable environment (Table 2). ...
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The glassy-winged sharpshooter, Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae), is an important insect vector of the xylem-limited plant pathogen Xylella fastidiosa Wells et al. that causes diseases in numerous plant species including food and feedstock crops, ornamentals and weeds. Both the pathogen and the vector are native to the Americas, and H. vitripennis has demonstrated high invasive ability but to date neither has been detected in Australia. The Australian wine grape, table grape, peach, plum, nectarine and citrus industries are particularly concerned about the arrival of X. fastidiosa and H. vitripennis because of the potential economic impact on these important commodities. Other commodity producers in Australia should also be concerned about this vector-pathogen, in particular the ornamental plant, avocado and olive industries. Past interceptions of H. vitripennis and the potential for X. fastidiosa to be moved in live plant material or within live vectors indicate the need for rapid detection of an incursion in areas considered at high risk. This requires identification of regions that have climatic and environmental conditions conducive to X. fastidiosa and H. vitripennis establishment as well as a detailed knowledge of their respective potential host plant ranges in new areas. These climatic regions and host plant species can then be targeted for monitoring in order to detect an incursion at an early stage. CLIMEX modelling has shown that much of coastal Australia has temperatures suitable for survival of both the vector and pathogen. A range of other requirements in addition to suitable climate must, however, be satisfied for an incursion to lead to establishment, proliferation and spread. This review article provides information that shows that the Australian environment is suitable for the establishment of H. vitripennis and that Australian native plant species are likely to serve as X. fastidiosa hosts and subsequent pathogen sources, and highlights future research directions.
... The establishment of H. vitripennis in California represents a serious threat due to its ability to vector Xylella fastiodosa Wells et al., a xylem-limited bacterium that causes Pierce's Disease in grapes (Davis et al., 1978), almond leaf scorch disease (Mircetich et al., 1976; Davis et al., 1980), and many other diseases in economically important woody crops. Since its initial detection, H. vitripennis has expanded its range in Southern California and can also be found in southern portions of the San Joaquin Valley (Blua et al., 1999) and Pacific islands such as French Polynesia, Hawai'i, and Easter Island (Grandgirard et al., 2006). q Mention of proprietary or brand names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval to the exclusion of others that also may be suitable. ...
Article
The glassy-winged sharpshooter, Homalodisca vitripennis (Germar), is native to the southeastern United States and northeastern Mexico. It was detected in southern California in the late 1980s and in the San Joaquin Valley in 1999, where it transmits the bacterium Xylella fastidiosa to grapevines and other crops. The reproductive success of hybrid and pure line H. vitripennis from two geographically separated populations in California (Riverside (RIV) and Bakersfield (BAK)) was evaluated under identical conditions. The RIV and BAK populations had different preoviposition periods that persisted through the second generation of each lineage. From adult molt, the preoviposition period in both female generations was significantly shorter for RIV (F₀ = 28.2 days and F₁ = 62.3 days) than BAK females (F₀ = 46.1 days and F₁ = 170.4 days). After a 21-day mating period, F₀ and F₁ females deposited on average 391 (range, 21-967) and 196 (range, 0-755) eggs, respectively, without significant differences in fecundity among the F₀ and F₁ mating pair treatments. Egg accumulation rates among F₁ treatments showed that females in the RIV groups rapidly deposited their eggs within the first 120 days after adult molt while BAK females maintained a steady accumulation rate during their life. The performance of both hybrid lines was intermediate between the pure lineages. The F₀ mating pairs: ♀RIV × ♂RIV, ♀RIV × ♂BAK, ♀BAK × ♂RIV, and ♀BAK × ♂BAK produced on average 185, 94, 79, and 0 viable eggs, respectively, which suggested a delayed sexual maturity of BAK males and females. The proportion of viable eggs deposited decreased gradually, which suggests that females completely exhausted sperm reserves. From a management perspective, delayed reproductive maturity and polyandry are weak links in H. vitripennis' biology that may be exploited through mating disruption or insect sterilization strategies to reduce population growth and augment pressure by natural enemies.
... (2007), most likely via the movement of ornamental plants. In the absence of the mymarid egg parasitoid Gonatocerus ashmeadi, dense leafhopper populations developed and retarded plant growth and fruit yields, and produced copious watery excreta (Grandgirard et al., 2006). Nymphs and adult leafhoppers were toxic to some generalist predators, in particular native spiders (Suttle and Hoddle, 2006). ...