Symptoms
- Nendran and Poovan are highly susceptible.
- Conspicuous chlorotic leaf streaks of varying sizes parallel to midrib and perpendicular to the leaf veins is the characteristic symptom
- Chlorotic to dark green streaks also appear on the midrib, petiole and pseudostem
- Subsequently these streaks become necrotic
- Most often necrotic streaks also appear on leaf veins, especially near to midrib
- Lamina gets reduced in size, become brittle and roll upward with mosaic mottling
- Thickening of veins brittleness of leaves
- In severe cases, newly formed leaves are represented by the midribs alone
- Affected plants seldom produce bunch
Procedure for Observation
Select five rows at random from 10 cent plot. Observe plants showing typical virus symptoms.
ETL
Mere presence
Spread of Disease
Control Measures
- The most important measure is to use only disease free planting material for propagation.
- The diseases should be detected early in the field and immediately eradicate infected plants including suckers.
- Affected plants can be destroyed by spraying kerosene or by injecting herbicides like 2-4 D
- Do not take suckers from infected fields
- Use tissue culture plants and certified disease free suckers for planting.
- Avoid growing leguminous and cucurbitaceous vegetables as inter crops.
- Before planting spread lemon grass in the pit,(if available)
- Apply cartap hydrochloride 4 G @ 25 g per plant 20 days after planting. A second and third dose of the chemical are to be applied in the leaf axil @ 12.5.g each at 65 days and 165 days after planting.
- Spray Verticillium lecanii to control aphid vectors @ 20 g or 5 ml /l at 25,65 and 165 days after planting . Where ever insecticides are applied 10 day gap should be given for biocontrol application.
- Apply neemcake @ 1 kg in two split doses 25 -30 days after planting and the second at 60-65 days after planting.
- Predators of banana aphids include lady bird beetles (Symnus nubilus, Pseudaspidimerus circumflexa , Micraspes crocea, Menochilus sexmaculatus) Syrphids (Paragus serratus, Ascarina spp.) and a Hemerobid. Protect these natural enemies.
- Varieties such as Karpooravalli,kanchikela, Njalipoovn and koombillakannan are tolerant against bunchy top infection.