Brinjal

Nematode Management


Nematode Management

Introduction

  • The root-knot nematode, Meloidogyne spp. and reniform nematode Rotylenchulus reniformis are the major nematode pests, causing serious damage to brinjal.
  • These nematodes weaken the growth and vigour of the plants and pre-dispose the roots to invasion by many root-rot and wilt causing fungi and bacteria compounding the damage.
  • The host range of these nematodes is very extensive, including most vegetables belonging to many families.

Root-Knot Nematode

  • The second stage juvenile of the root-knot nematode penetrates the growing root tip and fixes a feeding site in the cortex, as a sedentary endo-parasite.
  • The nematode matures in 20-25 days and lays about 200-300 eggs in a gelatinous matrix on the infested root.

Symptom

  • The plants show unthrifty development and stunted growth if the infection has been severe.
  • The leaves are yellowish green to yellow, tend to drooping and then there is sudden wilting if wilt organisms are present.
  • Sometimes, there is scorching of the leaf from the margin inward.
  • These symptoms, however, overlap with symptoms of many other diseases.
  • The most characteristic symptom of the disease is the formation of knots or galls on the root system.
  • The main root and the laterals bear spherical to elongated galls which vary in size from very small to very large.
  • In advanced stages the galled tissues decay and are invaded by other pathogenic and saprophytic organisms.

Reniform Nematode

  • The reniform nematode penetrates the secondary and tertiary roots and causes necrotic lesions.
  • The female is attached to the root as a semi-endoparasite with its posterior kidney shaped body protruded outside the root.
  • An adult female lays 50-75 eggs in gelatinous matrix.

Symptom

  • The infected plants shows multitude of symptoms viz., stunting, leaf curling and chlorosis, inhibition of root development, root discolouration and necrosis, cortical necrosis, premature dropping of flowers, malformation of fruits and seeds.
  • Apart from this direct damage, injuries caused to the roots due to penetration by the nematodes facilitate easy entry to soil-borne fungal pathogens viz., Phytophthora and Fusarium, causing root rot and wilt diseases.

Factors responsible for nematode disease

  • Excessive soil moisture coupled with lack of aeration favours the nematode development.
  • Sandy and light soils favours their movement best.
  • Generally, temperatures of 25 to 28o C are best for infection, rapid multiplication of root-knot nematodes.

Management

  • Summer ploughing and exposing the soil to sunlight for one or two months during April-May prior to planting helps to reduce the nematode and pathogen load in the soil.
  • Provision of good drainage and avoidance of water stagnation.
  • Use healthy seedlings for planting.
  • Crop rotation with non solanaceous crops such as paddy, gingelly, pulses, groundnut helps in reducing the build up of nematodes in soil.
  • Rotating brinjal with marigold helps to reduce the nematode incidence for the next crop.
  • Soil application of VAM-endomycorrhiza Glomus fasciculatum to nursery bed @ 2 kg/metre2 cent suppress nematode infection and helps in production of vigorous seedlings.
  • Nursery soil may also applied with nematode antogonist and plant health promoting bacteria, Pseudomonas fluorescens @ 1 kg/metre2 cent at the time of seed sowing to further ensure nematode elimination.
  • Application of neem cake @ 750-1000 kg per hectare or saw dust @ 2 tonnes per hectare gives good control.
  • Soil application of nematicides such as carbofuran 33 kg/ha or phorate @ 10 kg per ha at the time of earthing up on 30 DAT gives almost complete control of nematodes if applied within a week after transplanting.

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Tamilnadu

Brinjal

Brinjal Management