Aconophora compressa is a gregarious, sapsucking insect that uses multiple host plant species. Nymphal host plant species (and variety) significantly affected nymphal survival, nymphal development rate and the subsequent size and fecundity of adults, with fiddlewood (Citharexylum spinosum) being significantly best in all respects. Nymphs that developed on a relatively poor host (Duranta erecta var ''geisha girl'') and which were moved to fiddlewood as adults laid significantly fewer eggs (mean ± SE = 836 ± 130) than those that developed solely on fiddlewood (1,329 ± 105). Adults on geisha girl, regardless of having been reared as nymphs on fiddlewood or geisha girl, laid significantly fewer eggs (342 ± 83 and 317 ± 74, respectively) than adults on fiddlewood. A simple model that incorporates host plant related survival, development rate and fecundity suggests that the population dynamics of A. compressa are governed mainly by fiddlewood, the primary host. The results have general implications for understanding the population dynamics of herbivores that use multiple host plant species, and also for the way in which weed biological control host testing methods should be conducted.
Frankliniella occidentalis (Pergande), western flower thrips (WFT), is a major worldwide pest of vegetables and ornamental crops. The biology of WFT was examined on gerberas, chrysanthemums and roses in relation to plant stage (flowering and non-flowering), pupation site, soil moisture and plant parts often inhabited by adult and immature thrips. Four foliage thrips predators (Transeius montdorensis (Schicha), Orius armatus (Gross), Mallada signata (Schneider) and Neoseiulus cucumeris (Oudemans)) and three soil predators (Geolaelaps aculeifer (Canestrini), Steinernema feltiae (Filipjev) and Dalotia coriaria (Kraatz)) were studied to determine their ability to reduce the numbers of WFT on gerberas, chrysanthemums and roses. There was no difference in the number of adults that emerged from growing media of high or low moisture content on any host plant. There were also no differences in the total numbers of WFT recaptured from flowering gerberas, chrysanthemums or roses. However, about seven times the number of thrips were collected from flowering chrysanthemums compared with non-flowering chrysanthemums, indicating that the flowering plants were more suitable hosts. Of all thrips recollected, the greatest percentage was immature (larval and pupal) thrips (70%, 71% and 43%) on the flowers for gerberas, chrysanthemums and roses, respectively. The mean percentage of thrips that emerged as adults from the soil was very low (5.3 Ϯ 1.2, 8.5 Ϯ 2.9, 20.5 Ϯ 9.1 and 28.2 Ϯ 5.6%) on gerberas, flowering and non-flowering chrysanthemums, and roses, respectively. Simultaneous release of foliage and soil predators did not reduce the number of thrips beyond that caused by foliage predators alone. Of the foliage predators, T. montdorensis, O. armatus and N. cucumeris performed best, significantly reducing the numbers of adult and immature thrips on flowers and foliage by 30-99%. Further research is required to determine the most cost-effective rates of release in cut flower crops.
Weed biocontrol relies on host specificity testing, usually carried out under quarantine conditions to predict the future host range of candidate control agents. The predictive power of host testing can be scrutinised directly with Aconophora compressa, previously released against the weed Lantana camara L. (lantana) because its ecology in its new range (Australia) is known and includes the unanticipated use of several host species. Glasshouse based predictions of field host use from experiments designed a posteriori can therefore be compared against known field host use. Adult survival, reproductive output and egg maturation were quantified. Adult survival did not differ statistically across the four verbenaceous hosts used in Australia. Oviposition was significantly highest on fiddlewood (Citharexylum spinosum L.), followed by lantana, on which oviposition was significantly higher than on two varieties of Duranta erecta (''geisha girl'' and ''Sheena's gold''; all Verbenaceae). Oviposition rates across Duranta varieties were not significantly different from each other but were significantly higher than on the two non-verbenaceous hosts (Jacaranda mimosifolia D. Don: Bignoneaceae (jacaranda) and Myoporum acuminatum R. Br.: Myoporaceae (Myoporum)). Production of adult A. compressa was modelled across the hosts tested. The only major discrepancy between model output and their relative abundance across hosts in the field was that densities on lantana in the field were much lower than predicted by the model. The adults may, therefore, not locate lantana under field conditions and/or adults may find lantana but leave after laying relatively few eggs. Fiddlewood is the only primary host plant of A. compressa in Australia, whereas lantana and the others are used secondarily or incidentally. The distinction between primary, secondary and incidental hosts of a herbivore species helps to predict the intensity and regularity of host use by that herbivore. Populations of the primary host plants of a released biological control agent are most likely to be consistently impacted by the herbivore, whereas secondary and incidental host plant species are unlikely to be impacted consistently. As a consequence, potential biocontrol agents should be released only against hosts to which they have been shown to be primarily adapted.
Alstroemeria (Liliales: Alstroemeriaceae) is a plant genus native to South America with many interspecific hybrids cultivated as ornamentals worldwide. Several yellow larvae of an undescribed gall midge (Diptera: Cecidomyiidae) were found feeding inside flower buds of Alstroemeria plants grown in production greenhouses in South Australia in 2013; Queensland, Australia, in 2015 and the Netherlands in 2016. Infested buds became malformed, did not produce flowers and turned necrotic later. In Queensland and the Netherlands, the necrotised buds became additionally infected by a saprophytic fungus Cladosporium sp. With up to 80% of flower buds infested, the new gall midge decreased the value of plants aimed for the cut flower market and reduced seed of reproduction plants. The new species, named Contarinia jongi Kolesik sp. nov., is described, and a segment of its Cytochrome Oxidase unit I mitochondrial gene is sequenced. This is the first gall midge known to feed on a host plant from the family Alstroemeriaceae. Previously, Alstroemeria cut flowers imported from Australia and New Zealand to Japan were found to contain viable larvae of the new species, demonstrating that the new species can spread with the flower trade. It is possible that Contarinia jongi is native to South America, the homeland of its host plant.
Vital for a game of cricket or golf and enjoyable when picnicking in the park, turfgrass provides a wide range of aesthetic and recreational benefits. However, managed turfgrass is prone to damaging outbreaks of insects and mites. Pest Management of Turfgrass for Sport and Recreation is the first comprehensive work on the plant-eating insects and mites of the grass and non-grass species currently maintained as ornamental lawns and turfgrass playing surfaces throughout Australia, the South Pacific and South-East Asia. This book provides an industry reference for the identification of pests affecting the roots, stems and leaves of turfgrass and control of these species through integrated pest management. It contains information on the distribution, ecology and biology of pests and how to monitor them. The integrated pest management approach outlined in the book includes natural environmental controls, beneficial and predatory species of arthropods, resistant cultivars and insecticidal and miticidal pesticides. Pest Management of Turfgrass for Sport and Recreation is an essential manual for managers of sportsgrounds, bowling greens, lawn tennis courts, golf courses, racecourses, ornamental landscapes, amenity parklands, public reserves and turfgrass production farms.
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