AWA: Academic Writing at Auckland

Management recommendations report

Compiled by Stephanie Morton

Incursion details:

Two live adult Homalodisca vitripennis (common name: Glassy-winged sharpshooter) have been captured in Villa Maria Estate vineyard located at 118 Montgomerie Rd, Mangere, Manukau just north of Auckland international airport (see figure 1). Positive identification was made by taxonomists from the Ministry of Primary Industries on the 20^th of July 2017 and an incursion response team has been appointed.

Figure 1. Incursion location 118 Montgomerie Rd, Mangere, Manukau.

Incursion Location (indicated exactly with an arrow in the assignment)  

 

Species description

Homalodisca vitripennis (also known as Homalodisca coagulate) is a leaf hopping insect belonging to the family Cicadellidae, originating from the south-eastern borders of the United States and Northern Mexico (Takiya, McKamey, & Cavichioli, 2006). Adult Individuals are approximately 14mm in length with dark brown/black colouration, a mottled yellow upper head, and semi-transparent wings with reddish veins (Ministry of Primary Industries, 2017; University of California Television, 2008). They are generalist feeders with >130 different host plants including; grape, citrus, almond, pine, oleander, eucalyptus, Leptospermum spp., and Hebe spp. (Daane & Johnson, 2003; Hoddle, Triapitsyn, & Morgan, 2003; University of California Television, 2008). They feed with sucking mouth parts that can inject both woody and soft tissue plant stems and leaves (Hummel, Zalom, & Peng, 2005). They excrete a waste that, once evaporated, crates a white film that can be seen on leaves where it falls (University of California Television, 2008).

There are three life stages:

• Eggs- Between 3-28 eggs are laid within the soft tissue of leaves, making them very inconspicuous to find (Tipping et al., 2005; Varela, Hashim-Buckey, Wilen, & Phillips, 2016). In California the glassy-winged sharpshooter (GWSS) lay 2 generations per year that hatch within 10-14 days (Varela et al., 2016).
• Nymphs- Nymphs feed on plant xylem. They move by crawling or hopping (up to 40cm in third instars, and up to 1m in fifth instars) preferably across connecting plant canopy’s (Tipping, Mizell, & Andersen, 2004). Development from nymph to adult is dependent on plant host nutrient quality, temperature, and light/dark cycles (Krugner, 2010; Mizell et al., 2008; Son et al., 2010). It can take around 40 days to reach full maturity on Vitis vinifera in California, and up to 70 days on Leptospermum species (Manuka genus) in Australia (Rathé et al., 2014).
• Adults- Adults feed on plant xylem, and often host switch for different nutrient sources(Northfield et al., 2009). Consumption rates of xylem can be up to 100 times dry body weight per day and are at their highest during midday (Brodbeck, Mizell, & Andersen, 1993). Adults crawl, hop or fly from plant to plant (Brodbeck, Andersen, & Mizell, 1995). Preferred migration is through plant corridors where they have shown to move up to 150m in 72 hours (Blackmer, Hagler, Simmons, & Henneberry, 2006). Adults are also strong flyers and been seen to fly up to 100m from their host plant in order to find a new food resource (Northfield et al., 2009).

Status

Legal status: Notifiable Organism  (Ministry of Primary Industries, 2017)

The GWSS is a major agricultural pest in North America, Tahiti, French Polynesia and surrounding islands, due to its role as a prolific plant disease vector (Grandgirard, Hoddle, Petit, Roderick, & Davies, 2008; Ministry of Primary Industries, 2017; University of California Television, 2008).

Potential damage: Facilitates the transfer of Xylella fastidiosa bacteria (NOT currently present in New Zealand) causing Pierces disease in grape vines, almond leaf scorch, oleander leaf scorch, cherry plum leaf scorch, phony peach disease, plum leaf scald, sycamore leaf scorch, oak leaf scorch, and variegated citrus chlorosis (Mizell et al., 2008; University of California Television, 2008; Varela et al., 2016). It is expected to also affect plant exports with quarantine restrictions (Petit, Hoddle, Grandgirard, Roderick, & Davies, 2008).

The current incursion is located on grape vine species, a known plant host, which can support all three life stages, and support nutritional requirements during wintering periods with over 90% survival rates (Almeida, Wistrom, Hill, Hashim, & Purcell, 2005; Hummel et al., 2005). This is a high priority organism located in a potentially ideal habitat for establishment.

 

Extent of infestation  

Site notes: 45 Ha estate with 22,987 grape vines planted over 9.93 Ha (B. Donaldson, personal communication, August 2, 2017). Vines have already lost their foliage and partially undergone cordon pruning reducing some vines to solitary trunks (B. Donaldson, personal communication, August 2, 2017). Vines are planted 1-1.5m apart. There are vegetation corridors around the perimeter of the property and a few vegetation corridors running along properties outside of Villa Maria estate. These include potential hosts; Grevillea sp. (Silky Sheoak), Metrosiderous sp. (Pohutakawa), Salix sp. (Willow tree), Alder sp. (Flax), Prunus sp. (stone fruit trees) (B. Donaldson, personal communication, August 2, 2017, California Department of Food and Agriculture, 2017). Average temperature for July 2017 is 11.5°C, and light dark cycles 10:14 (Light: Dark) (Brandolino, 2017).

GWSS ecology notes: If present GWSS will most likely be in a depressed state, juvenile instars will be relatively confined to one vine or row as 1m is the upper limit of their jumping capability (Tipping et al., 2004). Feeding rates will be reduced or possibly paused as feeding appears to cease around 10°C (Johnson et al., 2006). Adult females are likely to be in diapause which occurs at <13.5 :> 10.5 (Light: Dark) threshold (Mizell et al., 2008; Pollard & Kaloostian, 1961).

Delimiting survey:

• Local area survey- Sticky traps have been found to be the most successful monitoring technique for GWSS (Puterka, Reinke, Luvisi, Ciomperik, & Bartels, 2003) and are recommended for the delimiting survey. Finding both the outer limits of dispersal as well as the distribution gradient are important as clustering patterns can indicate the level of establishment (Petit et al., 2008). Therefore, yellow sticky trap boards should be placed across the Villa Maria estate and surrounding properties as displayed in figure 2. Sticky traps will be placed on every second vineyard bay (at approximately 2m high) around the perimeter of the vine blocks, alternating between the exterior row and second row in. Sticky bands will be placed on the vine trunks to catch any crawling nymphs as adults alone may be hard to detect in winter conditions (Pollard & Kaloostian, 1961). Sticky bands will also run along a central transect perpendicular to the rows, in each of the eight blocks of vines as nymph dispersal is generally along vegetation corridors, see figure 2 (Gunawardana, Ashcroft, Braithwaite, & Poeschko, 2008).

A second perimeter of yellow sticky traps will line the trees along the edge of the property to monitor if the GWSS has host shifted to the known species listed above (Brodbeck et al., 1995; Puterka et al., 2003). Lastly it is recommended any known or suspected host plant species located within 200m of Villa Maria estate will be surveyed with yellow sticky traps to monitor adult winged dispersal (Blackmer et al., 2006; Northfield et al., 2009).

Traps will be checked daily in late afternoon, after their most active period during the warmest part of the day, for the first week (Blackmer et al., 2006).

Visual inspections of vines and sweep net inspections on low shrubbery/grassy areas are also recommended within in the incursion zone for the first two days to supplement the sticky trap capture data for the delimiting survey (Blua, Redak, Coviella, & Akey, 2002).

• Pathways survey- Any locations that have received soil or plant materials from Villa Maria estate will be checked and surveyed with sticky traps, starting with records from the last 12 months and going back further if the delimiting determines an earlier establishment. Eggs have been known to attach to woody stems as well as leaf tissue and may have gone offsite with these materials (Varela et al., 2016).

Sticky traps will be placed on known plant hosts located within 200m of the airport. Live adults are frequently found in airplanes within French Polynesia (Petit et al., 2008). If incursion was through this pathway we will expect to observe populations of GWSS in this area.

All wineries in the Auckland region will be contacted and alerted to the incursion and asked to check their vineyards thoroughly for GWSS. Wineries often trade goods and purchase from the same suppliers, GWSS presence on other vineyards will indicate if the incursion has originated from a stock supplier and if this incident is isolated or not.

• Maximum potential migration area- With weather data from NIWA and the Temperature dependent survival model developed by (Son et al., 2010) we recommend mapping out the potential extent of migration from the Villa Maria estate and survey likely plant hosts in the perimeter of this region. If GWSS are detected in the boundary the region should be expanded and extensively surveyed at the perimeter again until the outer limits where no GWSS are detected is reached.

Management approach 

Highest priority: Eradication

 

There has been no known complete eradication of the GWSS after population establishment. However, small scale local eradications have been achieved in areas of the United States (Hix, Toscano, Gispert, & County, 2003; Rathé et al., 2012). The GWSS is highly polyphagous with a wide plant host range covering many of New Zealand’s plant species including ornamental garden plants (oleander, rose, birds of paradise), crop species (grape, citrus), and potential native species such as Leptospermum (Manuka) (Hoddle et al., 2003; Rathé et al., 2014). Countries of prior invasion have had significant losses in crops due to vectoring of disease causing bacteria with no known permanent control solutions. A  recent incursion in California resulted in 25% grape vine losses in some regions over the first 3 years of incursion (University of California Television, 2008).

CLIMEX modelling has shown GWSS is likely capable of surviving in New Zealand’s climate (Hoddle, 2004), and it is expected to become an agricultural pest within New Zealand should it establish. It is speculative as to whether X. fastidiosa/Peirce disease will survive in conjunction with GWSS; however, there remains the possibility of species adaptation (Grandgirard et al., 2008; Hoddle, 2004).

Eradication would involve the application of neonicotinoids; a common low risk pesticide type already used in many vineyard pest control schedules (Hix, Toscano, et al., 2003) (B. Donaldson, personal communication, August 2, 2017). Vines are also easily accessible at this time of year without any crop or foliage. Eradication techniques available should not have a significant impact on human health nor is expected to affect the land owner’s 2018 grape vintage.

Regional containment of GWSS is infeasible. Migration patterns are typically linked to human movement in agricultural and urban settings, mostly through plant translocations. New Zealand also has numerous present plant species that can provide migration bridges for the GWSS as well (Petit et al., 2008). Climate may restrict some movement or reduce fecundity of GWSS in colder areas and higher altitudes; however spread is highly likely through the warmer regions particularly in the upper North Island (Charles & Logan, 2013; Grandgirard et al., 2008). Containment practices are only recommended if X. fastidiosa is found. Areas of X. fastidiosa incursion will need restricted movement orders on soil and plant matter, all infected plants destroyed and local eradication of GWSS undertaken.

 

Long term management is estimated to have a significant financial impact on the New Zealand agricultural industry. For native plants, the impact is unknown. There is a possibility that GWSS will not spread far from suburban and agricultural landscapes, and have a relatively slower life history attributed to a cooler climate (Grandgirard et al., 2008; Johnson et al., 2006). However, this species has high plasticity and species adaptation over time is a real risk.  Long term management does appear to be achievable with chemical and biological control techniques, but should only be considered if GWSS density levels have superseded the initial establishment phase and eradication is no longer plausible (Grandgirard et al., 2008; Hix, Toscano, et al., 2003). Plenty of research is still required for long term management practices within New Zealand, and as a result agricultural, garden and native plants can be expected to take an initial hit until management tools are tested and made available.  

Control techniques

 

Establishment phase categorization:

Given the high plasticity of the GWSS niche, incursion management will be dependent on the level of establishment determined by the delimiting survey. According to Petit et al. (2008) establishment can be divided into three stages.

1. Initial establishment- The population is confined to one or a few urban areas, density is low (<15 nymphs found per minute of sampling), distribution is clustered with higher density centers.
2. Intermediate invasion- The population is wide spread across many urban and semi urban areas, density is higher (<50 nymphs found per minute of sampling) in urban areas than semi urban areas.
3. Invasive population- The population is wide spread and has uniform density in urban and semi urban areas at high levels (>100 nymphs found per minute of sampling). The population is also present in undeveloped/natural landscape areas at lower densities (<5 nymphs found per minute of sampling).

Eradication:

If it is determined that the GWSS is in the ‘Initial Establishment’ phase then we recommended an eradication program be undertaken by MPI.

• Movement restrictions- Quarantine restrictions will be placed on Villa Maria estate, and any other properties in the designated incursion zone. No soil or plant material (fruit, vines, garden plants) can be taken out of the zone.
• Host removal- Vines will be tested for fastidiosa. If this is present, any affected vines will be removed and burnt. If X. fastidiosa it is not present, vines will be treated in situ for GWSS (Bextine, Blua, & Redak, 2003; Hix, Toscano, et al., 2003).
• Chemical control- Eradication of the GWSS will involve an intensive ground spraying and root injections program for all vine trunks and shoots, and surrounding host plants with a neonicotinoid pesticide (Imidacloprid) (Toscano et al., 2004). This will be applied once to the vines and surrounding plants, then tested to ensure required uptake thresholds are met. A minimum of 39ng Imidacloprid per cm ² of leaf, or 10ppb of Imidacloprid in the xylem sap must be achieved (Byrne & Toscano, 2007; Toscano et al., 2004; Tubajika, Civerolo, Puterka, Hashim, & Luvisi, 2007; Van Timmeren, Wise, & Isaacs, 2012).

The same spraying and root injection techniques will be used on all garden plants and low trees in the 200m buffer zone (see results of the delimiting survey for the total incursion area). Root injection techniques only, will be used on the taller trees.

Any known plant hosts located within 200m of the GWSS invasion zone must also be sprayed and root injected to create a containment barrier and avoid adult host switching and dispersal flight. This must be done 48 hours prior to incursion zone spraying for the pesticide to take effect and create a barrier. 

These techniques and pesticides will affect the nymph stages of the GWSS but not the eggs, and has a limited impact on adults.  Treatment must be continued for a duration of 2 months after the last adult is recorded in the sticky traps to ensure all adults are eradicated and all remaining eggs have hatched (Byrne & Toscano, 2007; Varela et al., 2016).

Long term management:

If incursion of the GWSS has reached the ‘Intermediate Invasion’ or ‘Invasive Population’ phase eradication will no longer be feasible and other options will need to be investigated. It is recommended that MPI work closely with industry stakeholders and DOC to achieve efficient management.  

• Biocontrol- A host specific parasitoid Gonatocerus ashmeadi appear to be having the largest impact on GWSS invasions, and will be looked into for possible New Zealand biocontrol of GWSS. Unfortunately with New Zealand’s climate this is not a promising avenue and Integrated Pest Management (IPM) strategy’s will also need to be put in place as contingency plans (Charles & Logan, 2013).
• Chemical control- Annual chemical spraying appears to be the next most effective method of control. Toscano et al (2004) has shown that two applications of 1ltr/HA Imidacloprid per year is optimum for Californian grape vines to resist GWSS. Two application means that wintering months can be covered as well as summer which is important as GWSS often winters on Vitus spp. Spraying should be done just prior to egg laying season (usually spring) to kill GWSS as it hatches and avoid as much damage as possible. However, this must be researched further in the New Zealand context as Imidacloprid may cause harm to important biocontrol’s (native or exotic) for other pest species such as cottony cushion scale or mealy bug, and help increase these pest populations (Grafton-Cardwell, Lee, Robillard, & Gorden, 2008). It may also negatively affect honey bee populations (Han, Niu, Lei, Cui, & Desneux, 2010). Integrated Pest Management strategies will need to be developed for other effected plant species as well.
• Heat destruction- Immediate removal and burning of any plants found to harbor fastidiosa is recommended.
• Movement restrictions- Should be placed on transporting plant and soil materials within New Zealand from known fastidiosa infected sites.
• Border control- Closer inspections of nursery stock coming into New Zealand from locations of known GWSS and fastidiosa establishment including but not limited too; Cook Islands, French Polynesia, California, and Mexico.  

Much more research is required for long term management in New Zealand. See Research Required section for more details.

 

Monitoring

Sticky traps have been found to be the most effective monitoring technique for GWSS (Blua et al., 2002; Hix, McGuire, & Puterka, 2003; Puterka et al., 2003; Tipping et al., 2004). Yellow  25cm² plates placed 2m of the ground to catch flying adults and sticky strips around the trunks of plants to catch crawling nymphs will be used.

 

During eradication:

During eradication intensive monitoring by sticky traps and sticky bands will be done in and around the vine plots similar to that done for the delimiting survey. Sticky traps will be placed near all the potential host trees around the perimeter of the property and within a 200m radius surrounding Villa Maria estate. These traps will be checked weekly for GWSS. Once the eradication is considered complete (estimated 2-4 months) most traps will be removed leaving a couple for continued surveillance to be checked monthly for one year. If no GWSS are found in this time eradication can be declared. It is also recommended that samples of adult GWSS are frozen and stored so that if a future incursion should occur genetic testing can be run to determine if the populations originated from the same incursion or a new pathway.

Long term:

Long term management monitoring will involve surveying of native plant species likely to become hosts to the GWSS. This will involve using sticky traps attached to native trees over the summer months within the Auckland region, particularly around the network of native bush areas. The purpose will be to establish the effect (if any) the GWSS has on more vulnerable native flora and the surrounding ecosystems before it reaches population thresholds that force dispersal into the rural/native settings.

If parasitoid wasps are brought in for biocontrol more intensive surveying is recommended like that achieved by Grandgirard et al. (2008) in French Polynesia. Distributions will need to be modelled across urban and rural areas spanning from the coast to the inland to establish where GWSS is present. Density surveys in selected locations will need to be done prior to biocontrol commencement and these will need to be continually monitored yearly from the same locations to see if biocontrol methods are having an effect on GWSS densities. 

 

Pathways

There are two likely pathways for this incursion. The first and more likely, is through nursery stock trade. Many common ornamental plants are known hosts for the GWSS (California Department of Food and Agriculture, 2017), and egg cases are relatively inconspicuous because they are oviposited into the leaf tissue of plants (Tipping et al., 2005). The second possible pathway is the translocation of live adults through aeroplanes from the pacific islands. The GWSS has recently invaded French Polynesia and surrounding islands through human transport channels (Gunawardana et al., 2008; Petit et al., 2008). Flight times between New Zealand and the Cook Island is around 4.5 hours which is within the GWSS starvation period, and GWSS have frequently been found on aeroplanes between the islands (Petit et al., 2008). Both of these pathways indicate this may not be an isolated incursion and follow up investigation is required.

A supplier trace will be conducted on all plant material products brought onto the Villa Maria estate over the past two years e.g. vines, cuttings and garden plants. Any batches that can be traced to other locations should be surveyed with sticky traps, and similar management protocols to Villa Maria estate will be run if GWSS is detected.

A sticky trap survey of the New Zealand international airport is recommended to determine if populations originated from here. If GWSS is detected the eradication zone will be extended to the airport. Biosecurity restrictions should be placed on aeroplanes from pacific islands with known infestations of GWSS and further biosecurity management practices discussed with the effected countries.

 

Research required

There has been a lot of work done to date on the GWSS ecology, and on effective and appropriate management techniques. However most research has been based in tropical climates and thus much of this work needs to be tested for its validity within a New Zealand context. We recommend the following areas for further research:

 

GWSS: For effective pest management we need to understand the annual life cycle of the GWSS including the high and low activity periods, reproductive periods, average number of eggs laid, and survival rates of all life stages. Most research has been conducted in California, French Polynesia, and the Cook Islands where the temperature ranges are ideal for GWSS establishment as well as invasion. Some research has overlapped with New Zealand comparable conditions but this is not enough to determine the growth, consumption, and fecundity rates that we will expect to see in New Zealand. Nor does this allow us to determine if the GWSS is capable of becoming invasive here (Mizell et al., 2008; Pollard & Kaloostian, 1961).  This information can be determined through lab rearing of GWSS under New Zealand climate range simulation (temperature, humidity etc.).

Xylella fastidiosa: Temperature simulation experiments need to be run on X. fastidiosa to determine the survival rates within New Zealand climate ranges.

The disease vectoring potential of New Zealand insect species that are xylophagous including any members of the order Hemiptera will need to be tested in lab to establish if these species will also need to be targeted for eradications in early X. fastidiosa incursions.

New Zealand plants: Plant palatability needs to be tested with any of New Zealand’s potential native host species e.g. Manuka, Hebe, Pohutukawa etc., and determine if survivorship through all life stages of the GWSS is possible on those plants.

We also need to monitor the impact GWSS and X. fastidiosa will have on those native plants including determining the minimum density of GWSS required to cause plant health issues, and determine if X. fastidiosa causes any types of disease in those plants. Much of this testing can be completed in the Pacific Island and USA where the same species exist as natives or are accepted garden ornamentals, and where X. fastidiosa already exists.

Other plant diseases: A survey of vineyards and citrus orchards for the presence of common plant diseases known to be (or capable of being) vectored by GWSS should be undertaken. This includes diseases that may be not visibly identifiable, or are symptomless but may impact other species if a vector is present. If diseases are detected mitigation measures need to be established in consultation with NZ Wine Growers Association, NZ Citrus Growers inc, MPI, and any other stake holders during this time before any agricultural impact is felt.

Boarder control: Potential incursion pathways need to be understood and managed more carefully. There needs to be more education programs developed around identification of GWSS and X. fastidiosa on New Zealand boarders, and regulations put in place to better manage nursery stock imports from countries of known GWSS and/or X. fastidiosa establishment such as the United States, Taiwan, Kosovo, Cook Islands, and French Polynesia (Hoddle, 2004).  

IPM techniques: Once GWSS ecology under New Zealand climate is established, and we have a better understanding of the life cycle of GWSS on each crop variety, chemical management plans need to be developed and integrated into the relevant IPM programs for each crop species that will be affected for optimal chemical control.

Biocontrol: Biocontrol techniques should be looked into as they have proven useful in other countries. However the first thing that must be determined is if the host specific parasitoid species native to the USA and Mexico are capable of surviving and reproducing in a New Zealand climate. Similar simulations to that of the GWSS note above can be run for this. Host switching possibilities of the selected biocontrol agents must also be thoroughly tested with any New Zealand species sharing similarities in biology with the GWSS.

 

References

 

Almeida, R. P. P., Wistrom, C., Hill, B. L., Hashim, J., & Purcell, A. H. (2005). Vector transmission of xylella fastidiosa to dormant grape. Plant Disease, 89(4), 419-424.

Bextine, B., Blua, M. J., & Redak, R. (2003). Developing a method to detect Xylella fastidiosa in the glassy-winged sharpshooter. Paper presented at the Symposium Proceedings.

Blackmer, J. L., Hagler, J. R., Simmons, G. S., & Henneberry, T. J. (2006). Dispersal of Homalodisca vitripennis (Homoptera: Cicacellidae) from a Point Release Site in Citrus. Environmental Entomology, 35(6), 1617-1625. doi:10.1603/0046-225X(2006)35[1617:DOHVHC]2.0.CO;2

Blua, M. J., Redak, R., Coviella, C., & Akey, D. (2002). Relationship between total population counts of glassy-winged sharpshooter and numbers obtained from various sampling methods. Paper presented at the Pierce’s Disease Research Symposium.

Brodbeck, B. V., Andersen, P. C., & Mizell, R. F. (1995). Differential utilization of nutrients during development by the xylophagous leafhopper, Homalodisca coagulata. Entomologia Experimentalis et Applicata, 75(3), 279-289. doi:10.1111/j.1570-7458.1995.tb01938.x

Brodbeck, B. V., Mizell, R. F., & Andersen, P. C. (1993). Physiological and behavioral adaptations of three species of leafhoppers in response to the dilute nutrient content of xylem fluid. Journal of Insect Physiology, 39(1), 73-81. doi:http://dx.doi.org/10.1016/0022-1910(93)90020-R

Byrne, F. J., & Toscano, N. C. (2007). Lethal toxicity of systemic residues of imidacloprid against Homalodisca vitripennis (Homoptera: Cicadellidae) eggs and its parasitoid Gonatocerus ashmeadi (Hymenoptera: Mymaridae). Biological Control, 43(1), 130-135. doi:10.1016/j.biocontrol.2007.05.007

Charles, J. G., & Logan, D. P. (2013). Predicting the distribution ofGonatocerus ashmeadi, an egg parasitoid of glassy winged sharpshooter, in New Zealand. New Zealand Entomologist, 36(2), 73-81. doi:10.1080/00779962.2012.751776

Daane, K. M., & Johnson, M. W. (2003). Biology and ecology of the glassy-winged sharpshooter in the San Joaquin Valley. Paper presented at the Proceedings, Pierce’s Disease Research Symposium, M. Athar Tariq, S. Oswalt, P. Blincoe, R. Spencer, L. Houser, A. Ba, and T. Esser (eds.).

Grafton-Cardwell, E. E., Lee, J. E., Robillard, S. M., & Gorden, J. M. (2008). Role of Imidacloprid in Integrated Pest Management of California Citrus. Journal of Economic Entomology, 101(2), 451-460. doi:10.1603/0022-0493(2008)101[451:roiiip]2.0.co;2

Grandgirard, J., Hoddle, M. S., Petit, J. N., Roderick, G. K., & Davies, N. (2008). Engineering an invasion: classical biological control of the glassy-winged sharpshooter, Homalodisca vitripennis, by the egg parasitoid Gonatocerus ashmeadi in Tahiti and Moorea, French Polynesia. Biological Invasions, 10(2), 135-148. doi:10.1007/s10530-007-9116-y

Gunawardana, D., Ashcroft, T., Braithwaite, M., & Poeschko, M. (2008). Bio-control for glassy-winged sharpshooter in Cook Islands. Biosecurity Magazine, 85, 12-13.

Han, P., Niu, C. Y., Lei, C. L., Cui, J. J., & Desneux, N. (2010). Use of an innovative T-tube maze assay and the proboscis extension response assay to assess sublethal effects of GM products and pesticides on learning capacity of the honey bee Apis mellifera L. Ecotoxicology, 19(8), 1612-1619. doi:10.1007/s10646-010-0546-4

Hix, R. L., McGuire, M. R., & Puterka, G. (2003). Development of trapping systems to trap glassy-winged sharpshooter (Homalodisca coagulata) adults and nymphs in grape. Paper presented at the Proceedings of the 2003 PierceÕs Disease Research Symposium, 9Ð11 December.

Hix, R. L., Toscano, N. C., Gispert, C., & County, R. (2003). Area-wide management of the glassy-winged sharpshooter in the Temecula and Coachella Valleys. Paper presented at the Symposium Proceedings.

Hoddle, M. S. (2004). The potential adventive geographic range of glassy-winged sharpshooter, Homalodisca coagulata and the grape pathogen Xylella fastidiosa: implications for California and other grape growing regions of the world. Crop Protection, 23(8), 691-699. doi:http://dx.doi.org/10.1016/j.cropro.2003.11.017

Hoddle, M. S., Triapitsyn, S. V., & Morgan, D. J. W. (2003). Distribution and Plant Association Records for Homalodisca Coagulata (Hemiptera: Cicadellidae) in Florida. Florida Entomologist, 86(1), 89-91. doi:10.1653/0015-4040(2003)086[0089:daparf]2.0.co;2

Hummel, N. A., Zalom, F. G., & Peng, C. Y. (2005). Fecundity and success of progeny produced by Homalodisca coagulata (Hemiptera: Cicadellidae) on single host species. J. Agric. Urban Entomol, 22(3&4), 151-158.

Johnson, M. W., Daane, K., Groves, R., Backus, E., Son, Y., Morgan, D., & Lynn-Patterson, K. (2006). Spatial population dynamics and overwintering biology of the glassy-winged sharpshooter in California’s San Joaquin Valley. CDFA PierceÕs Dis. Res. Sym. Proc. 12-15.

Krugner, R. (2010). Differential reproductive maturity between geographically separated populations of Homalodisca vitripennis (Germar) in California. Crop Protection, 29(12), 1521-1528. doi:http://dx.doi.org/10.1016/j.cropro.2010.08.014

Ministry of Primary Industries, M. (2017, 12 June 2008). Pest and disease search-Glassy-winged sharpshooter. Retrieved from http://www.mpi.govt.nz/protection-and-response/finding-and-reporting-pests-and-diseases/pest-and-disease-search?article=1484

Mizell, R. F., Tipping, C., Andersen, P. C., Brodbeck, B. V., Hunter, W. B., & Northfield, T. (2008). Behavioral Model for Homalodisca vitripennis (Hemiptera: Cicadellidae): Optimization of Host Plant Utilization and Management Implications. Environmental Entomology, 37(5), 1049-1062. doi:10.1603/0046-225X(2008)37[1049:BMFHVH]2.0.CO;2

Northfield, T. D., Mizell, I. I. I. R. F., Paini, D. R., Andersen, P. C., Brodbeck, B. V., Riddle, T. C., & Hunter, W. B. (2009). Dispersal, Patch Leaving, and Distribution of Homalodisca vitripennis (Hemiptera: Cicadellidae). Environmental Entomology, 38(1), 183-191. doi:10.1603/022.038.0123

Petit, J. N., Hoddle, M. S., Grandgirard, J., Roderick, G. K., & Davies, N. (2008). Invasion dynamics of the glassy-winged sharpshooter Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae) in French Polynesia. Biological Invasions, 10(7), 955-967. doi:10.1007/s10530-007-9172-3

Pollard, H. N., & Kaloostian, G. H. (1961). Overwintering Habits of Homalodisca coagulata , the Principal Natural Vector of Phony Peach Disease Virus. Journal of Economic Entomology, 54(4), 810-811. doi:10.1093/jee/54.4.810

Puterka, G. J., Reinke, M., Luvisi, D., Ciomperik, M. A., & Bartels, D. (2003). Particle Film, Surround WP, Effects on Glassy-winged Sharpshooter Behavior and Its Utility as a Barrier to Sharpshooter Infestations in Grape. Plant Health Progress. doi:10.1094/php-2003-0321-01-rs

Rathé, A. A., Pilkington, L. J., Gurr, G. M., Hoddle, M. S., Daugherty, M. P., Constable, F. E., . . . Edwards, O. R. (2012). Incursion preparedness: anticipating the arrival of an economically important plant pathogenXylella fastidiosaWells (Proteobacteria: Xanthomonadaceae) and the insect vectorHomalodisca vitripennis(Germar) (Hemiptera: Cicadellidae) in Australia. Australian Journal of Entomology, 51(3), 209-220. doi:10.1111/j.1440-6055.2011.00856.x

Rathé, A. A., Pilkington, L. J., Hoddle, M. S., Spohr, L. J., Daugherty, M. P., & Gurr, G. M. (2014). Feeding and Development of the Glassy-Winged Sharpshooter, Homalodisca vitripennis, on Australian Native Plant Species and Implications for Australian Biosecurity. PLoS ONE, 9(3), 1-10. doi:10.1371/journal.pone.0090410

Son, Y., Groves, R. L., Daane, K. M., Morgan, D. J. W., Krugner, R., & Johnson, M. W. (2010). Estimation of Feeding Threshold for Homalodisca vitripennis (Hemiptera: Cicadellidae) and Its Application to Prediction of Overwintering Mortality. Environmental Entomology, 39(4), 1264-1275. doi:10.1603/EN09367

Takiya, D. M., McKamey, S. H., & Cavichioli, R. R. (2006). Validity of <I>Homalodisca</I> and of <I>H. vitripennis</I> as the Name for Glassy-Winged Sharpshooter (Hemiptera: Cicadellidae: Cicadellinae). Annals of the Entomological Society of America, 99(4), 648-655. doi:10.1603/0013-8746(2006)99[648:vohaoh]2.0.co;2

Tipping, C., III, R. M., Brodbeck, B. V., Andersen, P. C., Hunter, W. B., & Lopez-Gutierrez, E. R. (2005). A Novel Method to Induce Oviposition of the Glassy-Winged Sharpshooter (Hemiptera: Auchenorrhyncha: Cicadellidae). Journal of Entomological Science, 40(2), 246-249. doi:10.18474/0749-8004-40.2.246

Tipping, C., Mizell, R. F., & Andersen, P. C. (2004). DISPERSAL ADAPTATIONS OF IMMATURE STAGES OF THREE SPECIES OF LEAFHOPPER (HEMIPTERA: AUCHENORRYNCHA: CICADELLIDAE). Florida Entomologist, 87(3), 372-379. doi:10.1653/0015-4040(2004)087[0372:DAOISO]2.0.CO;2

Toscano, N., Byrne, F., Castle, S., Learned, M., Paso Robles, C., Gispert, C., . . . Temecula, C. (2004). LABORATORY AND FIELD EVALUATIONS OF IMIDACLOPRID (ADMIRE), THIAMETHOXAM (PLATINUM), AND ACETAMIPRID (ASSAIL) AGAINST THE GLASSY-WINGED SHARPSHOOTER. Paper presented at the Proceedings, Pierce’s Disease Research Symposium.

Tubajika, K. M., Civerolo, E. L., Puterka, G. J., Hashim, J. M., & Luvisi, D. A. (2007). The effects of kaolin, harpin, and imidacloprid on development of Pierce's disease in grape. Crop Protection, 26(2), 92-99. doi:10.1016/j.cropro.2006.04.006

University of California Television, U. (2008). The Glassy-Winged Sharpshooter [Video file]. University of California Division of Agriculture and Natural Resources. Retrieved from https://www.youtube.com/watch?v=IJF9BaxwXBI

Van Timmeren, S., Wise, J. C., & Isaacs, R. (2012). Soil application of neonicotinoid insecticides for control of insect pests in wine grape vineyards. Pest Manag Sci, 68(4), 537-542. doi:10.1002/ps.2285

Varela, L. G., Hashim-Buckey, J. M., Wilen, C. A., & Phillips, P. A. (2016). Pest Notes: Glassy-winged sharpshooter. UC ANR publications 7492 Retrieved from http://ipm.ucanr.edu/PMG/PESTNOTES/pn7492.html.