Roome, R.E. (1975) Field trials with a nuclear polyhedrosis virus and Bacillus thuringiensis against larvae of Heliothis armigera (Hb.) (Lepidoptera, Noctuidae) on sorghum and cotton in Botswana. Bulletin of Entomological Research, 65 (3). pp. 507-514.
![[img]](http://eprints.icrisat.ac.in/style/images/fileicons/application_pdf.png) |
PDF
Restricted to ICRISAT researchers only |
Abstract
Six trials in Botswana in which an unpurified suspension of the local nuclear polyhedrosis virus (NPV) attacking Heliothis armigera (Hb.) was tested against larvae of this species on sorghum (five trials) and on cotton (one trial) during 1971-73 are described. A commercial preparations of the NPV of H. zea (Boddie) and one containing Bacillus thuringiensis were included in two of the trials. H. armigera NPV was as effective as a standard insecticide in preventing losses of sorghum in one trial. Lowering the rate of NPV reduced the control of H. armigera larvae. There was no difference in control achieved by spraying in the morning or in the evening. Spraying every second or every third row (relying on natural spread of the virus) reduced control. Low concentrations of molasses (0.6%) made control by 100 larval equivalents (L.E.) per hectare as good as that by 200 L.E. per hectare without molasses. Neither the commercial H. zea NPV nor the Bacillus preparation was as effective as the local virus. The local virus was reasonably effective against H. armigera on cotton at very high rates and with molasses. It was not as damaging as carbaryl to populations of egg parasites and predators, but the predators did not control injurious populations of aphids and Jassids on the virus-sprayed plots.ADDITIONAL ABSTRACT:H. armigera nuclear polyhedrosis virus (NPV) was applied in 5 trials to sorghum and in 1 trial to cotton in 1971-3. Control of H. armigera larvae in sorghum with doses of more than or equal to 100 larval equivalents (LE) of virus/ha was comparable with control by the standard insecticide, carbaryl. Lowering the rate of NPV or spraying every 2nd and 3rd row reduced control but control by 100 LE virus/ha + 0.6% molasses was comparable with control by 200 LE virus/ha. Commercial preparations of H. zea NPV and B. thuringiensis were not as effective as the local virus. The local virus gave reasonable control in cotton at 400-2000 LE/ha + molasses. Sorghum grain yields were increased from 2.5 t/ha in the untreated control to 3.4 t with 190 LE virus/ha and 3.1 t with 1.1 kg carbaryl/ha; seed-cotton yields increased from 0.02 t/ha in the untreated control to 0.7 t with NPV + molasses and 1.2 t with 0.5 kg carbaryl/ha
| Item Type: | Article |
|---|---|
| Author Affiliation: | Centre for Overseas Pest Research, London W8 5SJ, UK |
| Subjects: | Plant Protection |
| Divisions: | Sorghum |
| Depositing User: | Ms K Syamalamba |
| Date Deposited: | 20 Sep 2012 09:06 |
| Last Modified: | 20 Sep 2012 09:07 |
| Official URL: | http://dx.doi.org/10.1017/S0007485300006179 |
| URI: | http://eprints.icrisat.ac.in/id/eprint/8006 |
Actions (login required)
 |
View Item |
