Leafhoppers and Jassids (Hemiptera: Cicadellidae) BACK
Species complex
1. Leafhopper- Alebroides nigroscutulatus Dist. and Seriana equata Singh
2. Potato Leafhopper - Empoasca fabae Harris
3. Potato jassid - Amrasca devastans Dist.
4. Cotton jassid - Amrasca beguttula beguttula Isida
Distribution: Widely distributed over all the potato growing regions in India.
Host Range: Potato, tomato, other solanaceous plants, beans, celery, alfalfa and malvaceous crops.
Nature of damage and symptoms:
Nymphs and adults suck the cell sap from ventral surface of leaves.
Prolonged feeding causes Hopper Burn. Normally the older leaves below the growing tips burn first.
Lesions spread backward and inward from margins, eventually destroying entire leaflet.
Inject toxin with saliva, induces cell swelling, crushing phloem, disrupting movement of photosynthates in plants.
Feeding results in increase in plant respiration, depleting plant reserves.
More damage during early tuber bulking.
The species like Alebroides nigroscutulatus and Seriana equata damage the crop as vectors of phytoplasmal diseases, viz. Purple Top Roll (PTR), marginal flavescence (MF) and potato yellow dwarf virus (PYDV).
Leafhopper damage (Hopper Burn)
Identification
The eggs (about 1mm long) are pear shaped elongated and yellowish white in colour.
Nymphs are whitish pale green similar to adults but are smaller in the size and are wingless.
Adults
of both jassids and leafhoppers are wedge shaped, 2-3 mm long, pale green to
brown in colour.
Life cycle:
Eggs are laid in the stems of susceptible plants.
Each female lays 2-3 eggs per day and continues to oviposit for at least a month and up to 50 days, which hatches in 6-9 days (Fig 7).
Nymphs molt five times from 1st instar to adult in about two weeks, depending largely on temperature. The lower temperature threshold for development is estimated to be 8.4˚C, and the upper threshold to be 29˚C.
Nymphs feed primarily on the underside of the leaf.
Adult longevity is 5-8 weeks and there are 10-12 overlapping generations in a year.
Mating takes place 2-16 days after emergence.
Oviposition begins 2-7 days after copulation.
There is no true hibernation or diapause but the adults have the ability to tide over the adverse climatic conditions.
The pest appears with the onset of cloudy weather and their population is adversely affected after heavy monsoon showers. The ideal conditions for leafhopper and jassid development and multiplication is a temperature range of 27-36 ΊC. Relative humidity below 75% favors the multiplication of Jassids. No development occurs below 12-15 ΊC.
Figure : Life cycle of leafhoppers
Management:
The practice of adopting suitable crop rotations with non-host crops in pest prone areas and providing proper isolation to potato crop from susceptible hosts are the most useful management components for protecting the potato crop from A. devastans.
Delayed planting undertaken on 25th September for early crop and during middle of October for the main crop reduces the incidence and impact of the pest.
Judicious use of nitrogenous fertilizers, as higher doses of nitrogen makes the plant succulent and prone to hopper attack.
Soil application with Phorate 10G @ 10.0 kg/ha at the time of sowing.
Spraying the crop with insecticides like Dimethoate 30 EC @1ml or Methyl-Demeton 25EC @ 1.2ml or Imidacloprid 17.8 EC @ 0.4 ml or Thiomethoxam 25WG @ 0.3g per litre of water when leafhopper population reaches 5-10 adults per plant.