Biology, economic importance and management of sugar cane armyworms (Mythimna spp.) in Mauritius
| MSI05P4169 | |
| Ganeshan, S. | |
| University of London, London, GB | |
| Biology, economic importance and management of sugar cane armyworms (Mythimna spp.) in Mauritius | |
| Thesis, Ph.D. | |
| Thesis | |
| 2005 | |
| 161 pp.,35 figs, 30 tbls, 6 pl. | |
| En | |
| Every year, outbreaks of Mythimna spp. occur in young regrowths of machine-harvested sugar cane fields where trash-blanketing (the practice of leaving in situ the cane tops and dry leaves) is practised. The species composition of field populations was studied and five species were identified namely Mythimna pseudoloreyi, M. loreyi, M. insulicola, M. phaea and M. pyrausta. The first-named represented more than 76 per cent of the moths reared from field-collected larvae. The fecundity of M. pseudoloreyi averaged 668.4 and the adult female life span was 10.2 days. Moths fed on 10 per cent honey solution had a higher fecundity than those fed on 10 per cent sucrose solution. Water alone was unsuitable to sustain adult life. The incubation period was on average 3.5 days. The life cycle (from egg until death of the adult) was 50.0 days for males and 46.5 days for females. Trials indicated that fields damaged prior to October could recover. However, fields damaged after October did not recover and cane height was reduced by up to 16 per cent in totally defoliated plots. No significant decrease in cane height was observed in trials simulated in September. Trash removal and insecticide application to eliminate residual larval population did not have any positive effect on cane regrowth after damage. Indoxacarb, cyhalothrin L and thiodicarb proved to be effective for controlling the sugar cane armyworm. However, the chemicals affected two species of trash caterpillars Athetis ignava and Simplicia pannalis which feed on dry cane leaves. Larval parasitism was very high and the fungal pathogens Metarhizium anisopliae and Paecilomyces sp. were encountered on a few larvae and pupae. With the increasing machine-harvested area, the incidence of sugar cane armyworms is likely to increase. A sound pest management strategy should therefore be adopted so as not to antagonise the well-established biological control of sugar cane pests through injudicious application of insecticides. This strategy could comprise use of insecticides in fields damaged after October, application of insecticides only to cane rows at early stages of infestation after sampling for the presence of the pest. | |
| SUGARCANE PESTS MYTHIMNA Armyworms | |
| MAURITIUS | |
| Pests, pest control and management | |
| Insect pests: Armyworms | |
| 2005-07-01 | |
| En | |
| Mauritius Sugar Industry Research Institute | |
| 1 | |
| ENTO |