Scale Insects: Melanaspis glomerata
Symptom:
- The leaves of infested canes show signs of tip drying and unhealthy pale green colour and severe infestation causes yellowing.
- Severe decapping leads to non-opening of leaves, which also turn yellow and finally dry up.
- Infested crop losses its vigour, canes shrivel, growth is stunted and the internodal length is reduced drastically.
- Ultimately cane dries up. Such canes when slit open appear brownish red.
- Thick brown encrustations are seen on the nodal and internodal regions in severely affected canes.
Identification of pest:
- Nymph: Females multiply ovo-viviparously. The nymphs that hatch out from the eggs within the female’s body come out through the genital aperture. They are called ‘crawlers’. They settle after selecting a suitable site for feeding.
- Adult: Greyish black or brown circular scales, they cover the nodal region forming a thick encrustation.
Management:
Cultural method:
- Use resistant varieties like CO 439, CO 443, CO 453, CO 671, CO 691 and CO 692
- Select and plant the scale insect free setts.
- Keep the fields and bunds free from weeds.
- Avoid water stagnation in the field for a longer period.
- Avoid repeated ratoons.
Physical method:
- Detrash the crop at 150th and 210th day of planting.
- Setts should be dipped in dichlorvos at 1ml per lit of water and placed in cement bags with the mouth tied and transported to planting area
Biological method:
- Release Chilocorus nigritus (or) Pharascymnus horni egg card @ 5cc/ac
- Also release hymenopteran parasitoides like anabrotepis mayurai, cheiloneurus sp and predatory mites like saniosulus nudus and tyrophagus puttseartiae which feed on scale insect.
Chemical method:
- Pre-soak the setts in 0.1% solution malathion.
- Spray dimethoate @ 2ml/ lit along with sticker after detrashing.
- Apply contact insecticides like dichlorvos or any @ 2ml/lit of water by using hand sprayer.
Source-
- TamilNadu Agritech Portal
