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Field trials with a presistent stomach insecticide against populations of the red locust, Nomadacris Septemfasciata (Serv.), in an outbreak area

Published online by Cambridge University Press:  10 July 2009

G. J. W. Dean
G. J. W. Dean
Affiliation:
International Red Locust Control Service, Abercorn, Northern Rhodesia.
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Extract

In its potential outbreak areas in Northern Ehodesia and Tanganyika, sexually immature populations of adults of Nomadacris septemfasciata (Serv.) tend to concentrate in the islands of grass that remain unburnt after the annual fires that occur during the dry season. The locusts use the tall grasses as roosting sites and descend in the daytime to feed on adjacent short grasses, where these occur as constituents of an internal mosaic within the islands, or, in the case of islands composed wholly of tall grasses, on the fresh grass-shoots on the burnt-over ground surrounding them.

Two methods are described whereby emulsified solutions of dieldrin were applied in the Central Bukwa plain, Tanganyika, in 1960 as a stomach poison at dosages of 2·9 and 4·5 oz. active ingredient per acre from aircraft to the whole of individual islands showing the internal mosaic pattern (4 trials) or at 2·9, 4·5 and 8·2 oz. per acre to a swath 20 or 40 yd. wide around the perimeter of tall-grass islands (8 and 4 trials, respectively). Results were assessed by counting the numbers of locusts flushed by a vehicle driven along strips parallel to one another and 0·1 mile apart, and checked by counts of dead locusts. Mortality reached at least 90 per cent, within four days, at either dosage, following the first method, and 21–89 per cent, within 14 days following the second, being significantly greater at the higher dosages but not with the wider swath.

These results are compared with those obtained in preceding years by the standard method of applying DNC from aircraft at 20 per cent, in oil as a contact insecticide; in the latter case, the cost of insecticide was more per acre sprayed, but less per 1,000 locusts killed because the density (5 locusts per sq. yd. of grass island) in the trials was greater than in those using dieldrin (1 per 3 sq. yd.). Even so, when dieldrin was used, many more locusts were killed per sortie flown, and the total cost (of flying plus insecticide) per island was much less, and per 1,000 locusts killed very much less, than in the standard method, which nevertheless has to be used against mobile swarms because DNC is quick acting.

Type
Research Paper
Information
Bulletin of Entomological Research , Volume 54 , Issue 2 , August 1963 , pp. 349 - 359
Copyright
Copyright © Cambridge University Press 1963

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References

Albrecht, F. O. (1955). La densité des populations et la croissance chez Schistocerca gregaria (Forsk.) et Nomadacris septemfasciata (Serv.); la mue d'ajustement.—J. Agric. trap. Bot. appl. 2 pp. 109–192.Google Scholar
Burnett, G. F. (1951). Field observations on the behaviour of the red locust (Nomadacris septemfasciata Serville) in the solitary phase.—Anti-Locust Bull. no. 8, 36 pp.Google Scholar
Chapman, R. F. (1955). A laboratory study of roosting behaviour in hoppers of the African migratory locust (Locusta migratoria migratorioides R. & F.). —Anti-Locust Bull. no. 19, 40 pp.Google Scholar
Chapman, R. F. (1957). Observations on the feeding of adults of the red locust (Nomadacris septemfasciata (Serville)).—Brit. J. Anim. Behav. 5 pp. 60–75.CrossRefGoogle Scholar
Chapman, R. F. (1959). Field observations on the behaviour of hoppers of the red locust (Nomadacris septemfasciata Serville).—Anti-Locust Bull. no. 33, 51 pp.Google Scholar
Dean, G. J. W. & Maccuaig, R. D. (1961). Experimental spray trials, North Eukwa, June-July 1961.—A.L.R.U./Porton Rep. no. 3/61, 14 pp., multigraph. (Unpublished.)Google Scholar
Lea, A. & Webb, D. Van V. (1939). Field observations on the red locust at Lake Rukwa in 1936 and 1937.—Sci. Bull. Dep. Agric. S. Afr. no. 189, 81 pp.Google Scholar
Lloyd, J. H. (1959). Operational research on preventive control of the red locust (Nomadacris septemfasciata Serville) by insecticides.—Anti-Locust Bull. no. 35, 65 pp.Google Scholar
Pielou, E. C. (1952). Notes on the vegetation of the Rukwa Rift Valley, Tanganyika.—J. Ecol. 40 pp. 383–392.Google Scholar
Rainey, R. C., Waloff, Z. & Burnett, G. F. (1957). The behaviour of the red locust (Nomadacris septemfasciata Serville) in relation to the topography, meteorology and vegetation of the Rukwa Rift Valley, Tanganyika.— Anti-Locust Bull. no. 26, 96 pp.Google Scholar
Symmons, P. M., Dean, G. J. W. & Stortenbeker, C. W. (1963). The assessment of the size of populations of adults of the red locust, Nomadacris septemfasciata (Serv.), in an outbreak area.—Bull. ent. Res. 54 pt. 3.CrossRefGoogle Scholar
Vesey-Fitzgerald, D. F. (1955). The vegetation of the outbreak areas of the red locust (Nomadacris septemfasciata Serv.) in Tanganyika and Northern Ehodesia.—Anti-Locust Bull. no. 20, 31 pp.Google Scholar
Yates, F. (1949). Sampling methods for censuses and surveys.—318 pp. London, Griffin.Google Scholar