Rensburg, N.J. Van (1978) The effect of foliar sprays with broad spectrum organophosphates on the coccinellid and syrphid predators of grain sorghum aphids. Journal of the Entomological Society of Southern Africa, 41 (2). pp. 305-309.
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Abstract
Foliar sprays of methyl-demeton-S or methyl-demeton-S with parathion applied to fields of grain sorghum in South Africa in 1971 killed more than 99% of the aphids (Schizaphis graminum (Rond.) and Melanaphis sacchari (Zhnt.)) and 88-100% of the mobile instars of the (unspecified) coccinellid and syrphid predators present. The mortality of coccinellid eggs was 11-21% and pupae 0-16%, but the larvae from surviving eggs died from starvation, cannibalism or toxic residues. Adults from surviving pupae were not killed by the residues and dispersed from the fields. It is suggested that the longer spraying with broad-spectrum insecticides can be delayed the better, because predators, including their pupae, will become progressively more numerous relative to the surviving aphid populations. Preventive treatments before aphid colonies are in evidence are considered to be worse than useless
| Item Type: | Article |
|---|---|
| Author Affiliation: | Plant Protection Research Institute, Pretoria 0001, South Africa |
| Subjects: | Environmental Science |
| Divisions: | Sorghum |
| Depositing User: | Ms K Syamalamba |
| Date Deposited: | 16 Mar 2012 04:58 |
| Last Modified: | 16 Mar 2012 04:59 |
| URI: | http://eprints.icrisat.ac.in/id/eprint/3903 |
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