Intercrops, Cicadulina spp., and maize streak virus disease
ABSTRACT Intercrops of bean and finger millet were tested as a possible means of controlling maize streak virus disease (MSVD) in maize by disrupting the mating behaviour of the insect vectors of the maize streak virus, Cicadulina mbila and C. storeyi. A series of three trials were done. In the first, MSVD incidence 2 months after sowing was reduced to 14.9% and 17.4% in millet and bean intercrops compared to 29.5% in the pure maize stand. The number of male Cicadulina spp. caught on sticky pole traps was also significantly reduced relative to the control, but there was little effect on the catch of females. There was no significant yield penalty for the millet intercrop but maize yield was 49% lower in the bean intercrop treatment than in the pure stand. In the second trial, there were two millet and two bean intercrop treatments and a maize only control. Fewer male Cicadulina spp. were caught in the intercrop treatments relative to the control but MSVD incidence was reduced in one millet intercrop treatment only for which the associated maize yield penalty was 89%. In the final trial the bean intercrop was again tested but it had no effect on MSVD incidence. These experiments demonstrated that intercropping maize with bean or millet decreased vector activity and/or vector numbers. Vector catches were predominantly male, and catches of males but not females were reduced in the intercrop treatments compared with pure stands. However the lower vector catch was not consistently associated with a significant reduction in MSVD incidence, and when it was there was often an associated yield penalty in the maize due to the intercrop.
- [show abstract] [hide abstract]
ABSTRACT: The effect of population density of Cicadulina spp. in maize on the epidemiology of maize streak disease was investigated for irrigated crops planted in March or July at Salisbury, Rhodesia, from 1967 to 1969. Experimental plots of maize were invaded for 2–3 months following germination by Cicadulina adults leaving drying veld grasses. When there were few immigrant leaf-hoppers, incidence of maize streak increased arithmetically through transient settling and feeding of previously infective adults. Infection rates increased when infected plants were removed daily, presumably because of the disturbance of vectors.By comparison, large immigration populations (one leaf-hopper per three maize plants) resulted in an exponential increase in the incidence of maize streak infection.Aldicarb granules (10%) at 38 g per 12 m row length, applied into a furrow before planting the maize, gave almost complete protection from infection.Annals of Applied Biology 03/2008; 76(2):199 - 207. · 2.15 Impact Factor
- Journal of Insect Behavior 01/1997; 10(5):753-760. · 0.90 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: The probing activities of the most important leafhopper vector of maize streak virus, Cicadulina mbila (Naudé) (Hemiptera: Cicadellidae) were studied on different host-plants. Host preference was determined by giving the insects a choice of six plants, Digitaria sanguinalis, Zea mays, Zea perennis, Paspalum conjugatum, Oryza sativa and Saccharum officinarum (all Gramineae). Cicadulina mbila showed a strong preference for D. sanguinalis. Histological examination of plant tissues for salivary sheaths was used to reveal the preferred tissue. Cicadulina mbila tended to ingest from the phloem of its preferred hosts, and switch to mesophyll or xylem tissue on less preferred hosts. The suitability of each host was assessed by measuring the weight gain and amount of honeydew produced on each host by newly emerged adult females. Both parameters were greatest on the preferred host. Probing behaviour was also monitored electronically by recording the different waveform patterns produced when insects were probing, ingesting or not probing on the selected hosts. Cicadulina mbila probed less frequently, ingested longer and spent less time in non-probing activities on its preferred host, D. sanguinalis, although these responses were similar on maize and sugarcane. Rice induced poor probing responses and altered behaviour. This interpretation of the waveforms was supported by histological examination. As maize streak virus (MSV) is not found in phloem sieve elements, prolonged ingestion from sieve cells would not account for efficient acquisition from maize, which would require ingestion from other types of cells. D. sanguinalis was the host in which most ingestion from the phloem occurred, but it is the poorest source of MSV.Bulletin of entomological research 08/1995; 85(03):387 - 396. · 1.99 Impact Factor