Lloyd, R.J. and Franzmann, B.A. and Zalucki, M.P. (2007) Seasonal incidence of Stenodiplosis sorghicola (Coquillett) (Diptera: Cecidomyiidae) and its parasitoids on Sorghum halepense (L.) Pers. in south-eastern Queensland, Australia. Australian Journal of Entomology, 46 (1). pp. 23-28.
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Article Link(s): http://dx.doi.org/10.1111/j.1440-6055.2007.00577.x
Publisher URL: http://www3.interscience.wiley.com/cgi-bin/home
To quantify the role of Johnson grass, Sorghum halepense, in the population dynamics of the sorghum midge, Stenodiplosis sorghicola, patterns of flowering of Johnson grass and infestation by sorghum midge were studied in two different climatic environments in the Lockyer Valley and on the Darling Downs in south-eastern Queensland for 3 years. Parasitism levels of S. sorghicola were also recorded. In the Lockyer Valley, Johnson grass panicles were produced throughout the year but on the Darling Downs none were produced between June and September. In both areas, most panicle production occurred between November and March and infestation by S. sorghicola was the greatest during this period. The parasitism levels were between 20% and 50%. After emergence from winter diapause, one to two generations of S. sorghicola developed on S. halepense before commercial grain sorghum crops were available for infestation. Parasitoids recorded were: Aprostocetus diplosidis, Eupelmus australiensis and two species of Tetrastichus. Relationships between sorghum midge population growth rate and various environmental and population variables were investigated. Population size had a significant negative effect (P < 0.0001) on population growth rate. Mortality due to parasitism showed a significant positive density response (P < 0.0001). Temperature, rainfall, open pan evaporation, degree-days and host availability showed no significant effect on population growth rate. Given the phenology of sorghum production in south-eastern Queensland, Johnson grass provides an important bridging host, sustaining one to two generations of sorghum midge. Critical studies relating population change and build-up in sorghum to sorghum midge populations in Johnson grass are yet to be performed.
|Business groups:||Agri-Science, Crop and Food Science|
|Additional Information:||© Department of Primary Industries and Fisheries. © Australian Entomological Society.|
|Keywords:||Johnson grass; parasitoid; sorghum; sorghum midge.|
|Subjects:||Science > Zoology > Invertebrates > Insects|
Plant culture > Field crops > Grain. Cereals
Plant pests and diseases > Individual or types of plants or trees
Science > Biology > Ecology
|Deposited On:||25 Feb 2009 04:03|
|Last Modified:||25 Oct 2011 05:21|
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