caa a22 4500 388105240 CHVBK 20180307125335.0 cr unu---uuuuu 161130e199912 xx s 000 0 eng 10.1017/S1742758400018932 doi S1742758400018932 pii (NATIONALLICENCE)cambridge-10.1017/S1742758400018932 Origin of Outbreaks of Austracris guttulosa (Walker) in Australia and Nomadacris septemfasciata (Serville) in Southern Africa and Its Implications for Their Management [Elektronische Daten] Austracris guttulosa in northern Australia is similar to Nomadacris septemfasciata in the southern half of Africa in having one generation per year, mainly in tall grass plains that are seasonally flooded by rainfall and flooding rivers. Locusts survive the dry season as adults and after the early rains of the wet season, oviposit in bare areas. Young offspring nymphs hatch out and feed on adjacent short ephemeral grasses while older nymphs and young adults are in taller vegetation. While locusts usually do not breed well outside tall grass plains of the source area, rain is critical to overall population increase of A. guttulosa, allowing egg and nymphal survival in the normally dry open plains south of the source area. When such rain falls, a preventive control programme is instituted, which begins with forecasts of population increase in areas receiving rain for offspring survival; any high populations found are delineated for control. While swarms within the source areas are often not controlled, those further south nearer cropping areas usually are. Austracis guttulosa does not form bands, so control is usually left until the adult stage when swarms form. Current practice involves the use of chemical insecticides, though promising research indicates that the entomopathogenic fungus Metarhizium anisopliae may form part of an integrated pest management programme in the future. With N. septemfasciata, outbreaks seem to be related to dry periods, but the precise factors leading to outbreaks are not well understood. Until further research that allows accurate forecasting is undertaken, regular monitoring of outbreak areas and control of any bands and swarms that form will be an essential part of any preventive control programme. Both bands and swarms are present for long periods, giving ample opportunity for preventive control particularly in localities where crops are grown near outbreak areas. Copyright © ICIPE 1999 pullulation nationallicence le criquet à gorge éperon nationallicence Austracris guttulosa nationallicence le criquet nomade nationallicence Nomadacris septemfasciata nationallicence outbreak nationallicence spur-throated locust nationallicence Austracris guttulosa nationallicence red locust nationallicence Nomadacris septemfasciata nationallicence Hunter D. M. Australian Plague Locust Commission, GPO Box 858, Canberra, A.C.T Australia 2601 Spurgin P. A. Australian Plague Locust Commission, GPO Box 858, Canberra, A.C.T Australia 2601 International Journal of Tropical Insect Science Cambridge University Press 19/4(1999-12), 307-311 1742-7584 19:4<307 1999 19 JTI https://doi.org/10.1017/S1742758400018932 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S1742758400018932 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Hunter D. M. Australian Plague Locust Commission, GPO Box 858, Canberra, A.C.T Australia 2601 NATIONALLICENCE 700 1- Spurgin P. A. Australian Plague Locust Commission, GPO Box 858, Canberra, A.C.T Australia 2601 NATIONALLICENCE 773 0- International Journal of Tropical Insect Science Cambridge University Press 19/4(1999-12), 307-311 1742-7584 19:4<307 1999 19 JTI CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge