H. vitripennis is a large insect (about 13 mm). It is generally brown to black but the underside of the abdomen is whitish. The upper aspect of the head and thorax is brown or black with numerous ivory to yellowish spots. These spots allow H. vitripennis to be easily distinguished from its close relative, the native Californian smoke tree sharpshooter (Homalodisca lacerta), which has pale, wavy lines instead of the spots. The sausage-shaped eggs are laid side-by-side in masses averaging 10 to 11 eggs. The egg masses appear as greenish water blisters beneath the leaf. They are elongate, with the individual eggs running transversely across the mass. The nymphs are dark grey (first and second stage) to grey (third to fifth stage). The cast skin from the final nymphal moult to the adult often adheres to the stem or leaf surface (Phillips, 1998).
Yellow sticky traps are commonly used for surveillance and detection. Colour preferences for attraction to H. vitripennis are not well known, but it will fly to yellow. On warm nights it is attracted to black and incandescent lights. Active stages may be found by searching plant stems. Fresh egg masses are found on the underside of recently matured foliage (older foliage should be avoided). Active stages can be easily detected by placing a tarpaulin under the suspected host plant, at temperatures below 15°C, and striking the plant vigorously. A sweep net placed over the foliage can be used in a similar manner (Phillips, 1999a;Varela et al., 2001).
Related invasive species
- Homalodisca vitripennis
Related Farm Practice
- Damage
- Feeding
H. vitripennis is a stem feeder and leaves no visible symptoms of its feeding other than a white, powdery, dried excrement on plant surfaces.
Feeding causes no visible signs of damage, even though the insect consumes hundreds of times its body weight per day in xylem fluid. Most non-xylem-feeding leafhoppers produce a sugary or particulate excrement, but the excrement of xylem feeders is watery, high in ammonia and dries to a fine, whitish powder which can cover the stems, foliage and fruit when the insects are abundant (Phillips, 1998). High densities of feeding sharpshooters excrete enough waste product to cause a 'rain', which falls from the trees;this rain can easily be seen on sunny days and can be felt on the skin. This phenomenon is particularly acute in Tahiti where puddles form on roads and side walks as result of sharpshooter rain.
Egg masses are usually laid into recently expanded foliage. Older foliage will contain the distinctive scars left after the eggs have hatched. When populations are more abundant, egg masses can be laid into the rind of immature fruits of crops such as citrus and melon. Old hatched egg masses appear as grey or tan scars on surface of the rind (Blua et al., 1999).
As H. vitripennis continues to expand is range within California following its accidental introduction (ca 1989), both the ovipositional and feeding host lists continue to expand, primarily within ornamental plant species grown in nurseries or landscape gardens. As it is a xylem feeder, it circumvents secondary plant defence chemistry found in phloem sap and, as a result, it appears to be able to feed on most plant species. The high volume of xylem fluid intake required limits its survival to situations in which continued contact with a living host is possible. Only the egg stage is capable of survival for 2 or 3 weeks on excised plant foliage as long as it is kept fresh and moist.
H. vitripennis attacks plants in the following families: Aceraceae, Agavaceae, Amaranthaceae, Anacardiaceae, Apocynaceae, Aquifoliaceae, Araceae, Araliaceae, Asclepiadaceae, Asteraceae, Begoniaceae, Berberidaceae, Betulaceae, Bignoniaceae, Buxaceae, Caesalpiniaceae, Caprifoliaceae, Caprifoliaceae, Casuarinaceae, Celastraceae, Chenopodiaceae, Clusiaceae, Combretaceae, Convolvulaceae, Cupressaceae, Cycadaceae, Eleagnaceae, Ericeae, Euphorbiaceae, Fabaceae, Ginkoceae, Graminaceae, Hamamelidaceae, Iridaceae, Juglandaceae, Lamiaceae, Lauraceae, Liliaceae, Logaiaceae, Lythraceae, Magnoliaceae, Malvaceae, Meliaceae, Moraceae, Myoporaceae, Myrtaceae, Nyctaginaceae, Nyssaceae, Oleaceae, Onagaaraceae, Phytolaccaceae, Pinaceae, Pittospaceae, Platanaceae, Poaceae, Podocarpaceae, Polypodaceae, Proteaceae, Rosaceae, Rubiaceae, Rutaceae, Salicaceae, Sapindaceae, Sapotaceae, Saxifragaceae, Theaceae, Ulmaceae and Vitaceae.
H. vitripennis is native to the subtropical gulf states of south-eastern USA, in areas with a high water table where wild hosts produce the luxuriant growth necessary to sustain this prodigious xylem feeder. Its native range also includes the more arid regions of southern Texas and north-eastern Mexico, especially irrigated habitats such as landscape gardens and citrus orchards. After the recent introduction and spread of H. vitripennis in California, it has become extremely abundant on citrus and several ornamental and native plant species in southern parts of the state (Sorensen and Gill, 1996). Despite originating in a humid, subtropical region H. vitripennis can become abundant in Mediterranean climates if plants receive adequate irrigation and winter temperatures are not to severe.