Literature review: Impact of Chilean needle grass ... - Weeds Australia
Literature review: Impact of Chilean needle grass ... - Weeds Australia
Literature review: Impact of Chilean needle grass ... - Weeds Australia
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found in all mainland states, O. compositus is not known from Victoria or NSW. Other Pseudonampomyza spp. with angulate<br />
third antennal segments have host plants restricted to Poaceae, but no known <strong>Australia</strong>n hosts: P. probata Spencer, P. rara<br />
Spencer, P. salubris Spencer and P. pudica Spencer. Agromyza mellita Spencer and A. venusta, both known from northern<br />
Queensland have male genitalia with “the characteristic form <strong>of</strong> <strong>grass</strong>-feeders” (Spencer 1977 p. 122).<br />
Some Anthomyiidae (Diptera) also attack <strong>grass</strong>es including the wheat bulb fly Delia coarctata (Fallén), D. extreminata<br />
(Malloch) in Bromus in the USA, and Phorbia spp. mining stems and shoots (Ferrar 1987). Others are known to breed on<br />
Epichloe fungi on <strong>grass</strong>es (Ferrar 1987).<br />
Larvae <strong>of</strong> numerous Chloropidae species live in young shoots and stems <strong>of</strong> <strong>grass</strong>es and may feed largely on bacteria (Colless and<br />
McAlpine 1991) or be saprophagous rather than phytophagous (Ferrar 1987), however little is known <strong>of</strong> the biology <strong>of</strong><br />
<strong>Australia</strong>n species (Sabrosky 1989). Ferrar (1987) provided summary information on some pests <strong>of</strong> cereals and pasture <strong>grass</strong>es<br />
elsewhere in the world, plus a tabulation <strong>of</strong> the genera known from Poaceae. Most Chloropinae attack Poaceae or Cyperaceae, as<br />
do some Oscinellinae (Ferrar 1987). Some Oscinella species appear to be monophagous on particular <strong>grass</strong> species, while others<br />
have multiple known <strong>grass</strong> hosts (Ferrar 1987). Thirty-two Chloropidae spp., mostly endophages, have been collected from<br />
Phragmites, over 20 <strong>of</strong> which are monophagous (Witt and McConnachie 2004). Diplotaxa similis Spencer has been commonly<br />
found in the florets <strong>of</strong> Chionochloa spp. in New Zealand and has been viewed as the major seed predator, although they may<br />
actually <strong>of</strong>ten destroy the flower before seed formation, and there has been considerable confusion about whether the damage is<br />
caused by the chlropopid or Cecidomyiidae (Kelly et al. 1992). The wingless D. moorei (Salmon) Spencer is a predator <strong>of</strong><br />
Festuca novae-zelandiae author (Kelly et al. 1992).<br />
Some Ephydridae, mostly Hydrellini, attack <strong>grass</strong>es, and some are cereal pests, but most breed in aquatic situations or wet areas<br />
and feed on decaying matter, algae etc. (Ferrar 1987). Hydrellia spp. are recorded from Lolium, Poa, Pennisetum, Holcus,<br />
Panicum, Echinochloa and other <strong>grass</strong>es outside <strong>Australia</strong> (Ferrar 1987)<br />
Hemiptera<br />
Hemiptera also appear to have good representation on <strong>grass</strong>es. Specialist insects on Spartina alternifolia are mainly Hemiptera<br />
(Witt and McConnachie 2004). Among the Heteroptera, the Leptocorisini (Alydidae: Leptocorisinae) is closely associated with<br />
<strong>grass</strong>es and includes a number <strong>of</strong> rice pests, while the Stenodernini (Miridae) and Blissinae (Lygaeidae) are also <strong>grass</strong><br />
inhabitants (Ahmad 1965). Lygaeids are mostly seed eaters but the Blissinae (Chinch Bugs) feed on <strong>grass</strong> sap (Slater 1991).<br />
Subfamily Cyminae <strong>of</strong> Lygaeidae contains “small, brown bugs that live in seed heads and resemble seeds <strong>of</strong> various sedges and<br />
rushes” (Slater 1991 p. 502) and possibly includes some <strong>grass</strong> feeders. The pachygronthine Stenophyella macreta Horváth “is<br />
<strong>of</strong>ten common in seed heads <strong>of</strong> <strong>grass</strong>es” (Slater 1991 p. 502) and “appears to feed on a number <strong>of</strong> <strong>grass</strong>es even when they are<br />
completely dry” (Slater 1976 p. 135). Nabidae are predacious but oviposit in <strong>grass</strong> stems (Gross and Cassis 1991). Many <strong>grass</strong>feeding<br />
Homoptera have a narrow host range, but mealybugs Pseudococcidae and s<strong>of</strong>t scales Coccidae are generally<br />
polyphagous (Witt and McConnachie 2004).<br />
Farrow (1999) found that Cicadellidae (leafhoppers) were very numerous in <strong>grass</strong>lands in the <strong>Australia</strong>n Capital Territory and<br />
this family along with other planthoppers (Delphacidae, Eurymelidae, Flatidae, Membracidae, Ricanidae), froghoppers<br />
(Cercopidae), cicadas (Cicadidae) and allies, collectively classified in the suborder Auchenorryhncha, has been identified as a<br />
highly appropriate higher taxon for evaluation <strong>of</strong> the conservation significance <strong>of</strong> <strong>grass</strong>lands and monitoring environmental and<br />
habitat change, at least in Europe (Biedermann et al. 2005). They are diverse, with many rare species, wholy herbivorous, their<br />
numerical abundance supports higher trophic levels, and perhaps most importantly, rhey have high and rapid sensitivity to a<br />
range <strong>of</strong> disturbances (Biedermann et al. 2005). The European <strong>grass</strong>land fauna however is much better described than that <strong>of</strong><br />
<strong>Australia</strong>, baseline studies <strong>of</strong> whole faunas have been undertaken and some effects <strong>of</strong> <strong>grass</strong>land management on the faunas have<br />
been determined.<br />
Poaceae probably supports a higher diversity <strong>of</strong> <strong>Australia</strong>n cicadas (Cicadidae) than any other plant family, but few species<br />
inhabit the <strong>grass</strong>lands <strong>of</strong> the south-east (Moulds 1990). Nymphs <strong>of</strong> the <strong>grass</strong>-feeding species feed on <strong>grass</strong> roots, and the adults<br />
<strong>of</strong> some species oviposit in <strong>grass</strong> stems or leaves (Moulds 1990). Evans (1966) considered the cicadelloid fauna <strong>of</strong> <strong>Australia</strong>n<br />
<strong>grass</strong>es and herbs to be depauperate and <strong>Australia</strong>n <strong>grass</strong>lands to carry “a very small leafhopper population and ... even fewer<br />
cercopids” (p. 20) in comparison with other parts <strong>of</strong> the world. However Day and Fletcher (1994 p. 1119) noted that there had<br />
been “little systematic collecting” <strong>of</strong> Cicadelloidea in <strong>Australia</strong> and that distribution data was “very inadequate”. According to<br />
Evans (1966 p. 21) both Cicadelloidea and Cercopoidea were “not usually abundant on <strong>grass</strong>es” in <strong>Australia</strong>, and most <strong>grass</strong>frequenting<br />
species were introduced, but he acknowledged that records <strong>of</strong> food plants were very scanty. However Evans (1966 p.<br />
133) thought it “probable” that all species <strong>of</strong> Hecalini (Cicadellidae) are <strong>grass</strong>-feeders. Hecaleus arcuatus (Motschulsky) known<br />
from Queensland and outside <strong>Australia</strong> is recorded from T. triandra and Heteropogon (Day and Fletcher 1994). Day and Fletcher<br />
(1994) listed numerous species with known <strong>grass</strong> hosts in <strong>Australia</strong> but their designation <strong>of</strong> “host” is not rigorous; e.g. Evans<br />
(1966) stated that Mircrolopa minuta Evans was collected on <strong>grass</strong>es, which became in Day and Fletcher (1994 p. 1123):<br />
“Known hosts: Poaceae (Evans 1966: 87)”. Their host information “frequently reflects the plant species on which specimens<br />
were colleced and do not necessarily reflect the true hosts” (Day and Fletcher 1994 p. 1121).<br />
Hymenoptera<br />
Many ‘seed chalcids’ Eurytomidae (Hymenoptera) are host specific and different species develop in different positions within<br />
the culm (Witt and McConnachie 2004). They can cause major reductions in forage yield and seed weight, including a reduction<br />
<strong>of</strong> 60% in Heterostipa comata (Trin. and Rupr.) Barkworth, with consequent reduction in germinability (Witt and McConnachie<br />
2004). A Tetramesa sp. in Africa that bores in the stems <strong>of</strong> Sporobolus spp. was found to infest 33% <strong>of</strong> culms at one site.<br />
Infested culms were significantly shorter than uninfested and 60% had deformed infloresences (Witt and McConnachie 2004).<br />
The tribe Cephini <strong>of</strong> the sawfly family Cephidae consists <strong>of</strong> <strong>grass</strong>-mining specialists, a number <strong>of</strong> which are cereal pests, but is<br />
restricted to the Nearctic and Holarctic (Ivie 2001).<br />
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