Sugarcane
Sugarcane Scale
Melanaspis glomerata
Insect
In a Nutshell
- Drying of leaves and canes.
- Stunted growth.
- Stems and leaf midribs covered by circular, dark coloured scales.
Can also be found in
Sugarcane
Symptoms
Stems and leaf midribs are covered by circular, brown or greyish-black scales. Leaves of infested canes dry up at the tip, with an unhealthy pale green colour. The leaves later turn yellow with a continued infestation. The loss of sap also leads to the non-opening of the leaves, which ultimately turn yellow and dry up. Eventually, the cane dries up and appears brownish-red when slit opens. Infested canes become shriveled and the entire cane is covered with the pest forming encrustation on the stem in case of severe infestation. Due to its sedentary habits and minute size, the insect escapes the notice of the cane grower. Its existence is only revealed after severe damage has occurred.
Recommendations
Organic Control
Dip the setts in 1% fish oil rosin soap emulsion. Spray white oils (foliage and stalks), which show some effectiveness against young scales. Release Chilocorus nigritus or Pharascymnus horni egg card @ 5CC/AC. Introduce hymenopteran parasitoids such as Anabrotepis mayurai, Cheiloneurus sp. and predatory mites such as Saniosulus nudus and Tyrophagus putrescentiae, which can feed on the insect scale.
Chemical Control
Always consider an integrated approach with preventive measures together with biological treatments, if available. Soak setts in 0.1% of malathion solution before planting. Spray dimethoate @ 2ml/l or monocrotophos @ 1.6m/l after detrashing. Treat setts with acephate 75 SP @ 1g/l twice after detrashing, just before the initial appearance of the pest.
What caused it?
Damage is caused by the crawler's scales. Females are ovoviviparous - which means that the young ones are produced by eggs that are hatched within the body of the female. Upon hatching, the crawlers (young immature scales) wander about in search of a feeding site. They attach their needle-like mouthparts, extract the plant sap and do not move again. The infestation begins with the formation of the internodes and continues to increase as the cane plant grows. Plant sap is sucked by crawlers. In severe infestation, the leaf sheath, lamina, and midrib are also infested.
Preventive Measures
- Use resistant varieties such as CO 439, CO 443, CO 453, CO 671, CO 691 and CO 692.
- Cultivate the setts that are free from scale insects.
- Use clean planting materials to delay scale population build-up.
- Keep fields and bunds free from weeds.
- Drain stagnant water from fields.
- Monitor your field regularly for signs of infestation.
- Uproot and burn heavily infested sugarcane plants.
- Consider crop-rotation with a non-host crop (e.g.
- wheat).
- Detrash the crop at the 150th and 210th day of planting.
- Avoid repeated ratoons.
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