Cicadulina mbila (Naude) - Maize Leafhopper

Summary

The maize leafhopper has been recorded in sub-Saharan Africa, the Middle East, West Asia and India . Both adults and nymphs (juveniles) feed on plant juices which they extract by piercing into the plant tissue. This is in itself fairly harmless, but the specimens can transmit maize streak monogeminivirus (MSV) disease which can cause dwarfing or even plant death.

Common Names

Maize leafhopper (English)

Synonyms

Balclutha mbila Naudé

Taxonomic Position

Phylum: Arthropoda; Class: Hexapoda (Insecta); Order: Hemiptera; Suborder: Auchenorrhyncha; Superfamily: Cicadelloidea; Family: Cicadellidae

Origin and Distribution

The maize leafhopper has been recorded in several countries in sub-Saharan Africa (which includeKenya, Tanzania and Uganda) but these records are likely to be incomplete. There are also records from the Middle East, West Asia and India.

Description

Eggs

The smooth creamy-white maize leaf hopper eggs are elliptical and narrow, and approximately 0.3 to 0.5 mm long by 0.1 mm in diameter.

 

Nymphs

Early instar nymphs are pale green-yellow and are up to about half the size of the adult. Later instars look more like the adult insect with darker coloration appearing.

 

Adults

Adult maize leafhoppers are mostly pale yellow-green and very small (about 3mm long). Two small brown or black spots are found between the eyes on the front margin of the crown of the head. These leafhoppers have two small black spots and brown marks behind the eyes extending along the body. They have brown lines along the wings. The pronotum (plate-like covering of front segment of the thorax) also has dark markings and the dorsal surface of the abdomen has lateral dark banding. Females are distinguished by a black-tipped ovipositor (organ for depositing eggs).

Similar Species

Very similar in appearance to other Cicadulina species. 

Life Cycle

Fecundity longevity and development time vary considerably depending upon temperature and host plant, and may also vary between populations of different geographic origin. The female inserts several eggs into living tissue of the host plant. Lifetime egg production is greatest at around 28°C and may average more than 100 eggs per female. Eggs either remain dormant for a period ranging from a month to over a year, or develop and hatch within a few weeks. Nymphs undergo five moults, reaching the adult stage in several weeks or months. The nymphs and adults suck juices from the leaves of their host plant. In laboratory cultures at around 25°C, eggs hatch after 7-10 days and nymphal development is completed in a further 14 to 20 days. Adults can mate from 2 to 6 days following the final nymphal moult, though there is typically a rather longer period before egg laying. Mean adult life span at 26°C of males and females ranges 8-28 and 14-33 days, respectively, depending on host plant. Adults can disperse through flight.

Pest Destructive Stage

Nymphs and adult. Adult and nymphs feed on plant juices which they extract by piercing into the plant tissue. This is in itself fairly harmless, but the specimens can transmit viruses while doing so.

Host Range

The major concerns expressed about the maize leafhopper relate to its impact on maize but this does not seem to be its preferred host. Other hosts include those listed below:  oats, finger millet, barley, rice, millets, sugarcane, sorghum and wheat.

Host Lifestage Affected

The entire vegetative growth stage of the host plant.

Host Plant Part Affected

Leaves and other vegetative plant parts.

Damage Symptoms

The feeding activities of the maize leafhopper do not cause much direct damage. It exerts its negative impact through its ability to transmit maize streak monogeminivirus (MSV) disease. This causes yellow streaks to appear on the leaf which can result in plant death, dieback or dwarfing. The main damage is to plants younger than six weeks. In severely affected plants, the plants appear pale green, yellow or white from a distance, and are stunted and produce small cobs with open husks.

Pest Management

Detection methods

Maize leafhoppers are tiny and present at low densities so are difficult to detect. They can be collected from the plant using a pooter (aspirator) and later identified by an expert. Detection is mainly through observation of MSV damage symptoms - pale/yellowish streaks in the leaves which are quite easily spotted.

Cultural control

Maize leafhoppers move from hosts when they dry out or become otherwise unfavourable so cultural control depends on minimising the movement from other hosts. The following are possible cultural control methods:

·        Planting maize well away from previously irrigated cereals or grassland maximises the distance the leafhopper needs to travel from another host.

·        Creating a barrier of 10 m of bare ground between maize fields and previously infested crops which can reduce leafhopper movement and hence MSV incidence.

·        Removal of MSV-infected maize plants (rogueing) at an early stage.

·        Planting a large area of maize all at once is likely to make the crop less vulnerable to maize leafhopper infestation than planting in a staggered sequence. 

·        Keeping the fields free from weeds, in particular grasses.

·        Removing residues of cereal crops since they serve as infection sources.

 

Biological control
The authors could find no information on biological control programmes for this species.

 

Host-plant resistance

Resistant hybrid maize varieties are available. When using such varieties it is important to use certified seed at each planting.

Chemical control

Effective chemical control of maize leafhopper can be achieved by using persistent systemic insecticides, generally carbamates, applied either as a seed dressing or soil application at planting. Low persistence insecticides will not be effective as each new migration of individuals makes the crop vulnerable to virus transmission.Pesticides are poisons so it is essential to follow all safety precautions on labels.

Sources of Information and Links

CABI. (2007). Cicadulina mbila (Naude) (Maize leafhopper) datasheet. Crop Protection Compendium, 2007 Edition. CAB International Publishing. Wallingford, UK.

Guthrie EJ, Woods RD, 1974. Purification of maize streak virus and its relationship to viruses associated with streak diseases of sugar cane and Panicum maximum. Annals of Applied Biology, 77(3):289-296.

Infonet-Biovision. http://www.infonet-biovision.org/default/ct/91/pests. Accessed on 28 Jan 2011.

PaDIL - Diagnostic methods for South African maize leafhopper Cicadulina mbila.

PaDIL - Plant Biosecurity Toolbox. http://www.padil.gov.au/pbt | South African Maize Leafhopper – Cicadulina mbila Accessed January 16, 2011.

Editors

Anne M. Akol, Makerere University; Maneno Y. Chidege, Tropical Pesticides Research Institute; Herbert A.L. Talwana, Makerere University; John R. Mauremootoo, BioNET-INTERNATIONAL Secretariat.

Acknowledgments

We recognise the support from the National Museums of Kenya, Tropical Pesticides Research Institute (TPRI) - Tanzania and Makerere University, Uganda. This activity was undertaken as part of the BioNET-EAFRINET UVIMA Project (Taxonomy for Development in East Africa).

Contact

BioNET-EAFRINET Regional Coordinator: eafrinet@africaonline.co.ke