Skip to content

Pomegranate root-knot nematode

Root-knot nematode (Meloidogyne incognita) is the dominant nematode pest of pomegranate in India. The pest is widely distributed in commercial pomegranate orchards of Maharashtra, Karnataka and Andhra Pradesh and is a chronic productivity-reducing constraint in older, replanted blocks.

Identification and symptoms

Infested trees show patchy stunting, chlorosis and progressive decline despite adequate irrigation and fertilisation. Below ground, characteristic galls form on feeder roots and small lateral roots, disrupting water and nutrient uptake. In severe cases, root systems become a tangle of nodules and the tree fails to respond to the standard ahar-bahar crop-regulation treatment (Pomegranate Ahar Bahar Cycling).

Host crops and life cycle

Meloidogyne incognita is highly polyphagous and attacks vegetables, ornamentals and many fruit crops in addition to pomegranate. Females lay several hundred eggs in a gelatinous mass on the root surface; second-stage juveniles (J2) penetrate roots and induce giant-cell formation. Activity peaks at soil temperatures of 22-35 deg C and around 50-60% field capacity, conditions typical of irrigated semi-arid pomegranate orchards.

Damage and economic impact

Reviews of Indian field surveys report average yield loss of around 17%, with up to 40% reduction in fruit number and size in severely infested orchards. The nematode also predisposes pomegranate to wilt complexes with Fusarium and to bacterial blight (Pomegranate Anthracnose Bacterial Blight).

Management

Integrated management combines:

  • Cultural: pre-plant solarisation; raised beds; marigold (Tagetes) intercrops; rotation with non-host crops.
  • Organic amendments: heavy applications of well-decomposed farmyard manure or urban-derived foliage (UDF) compost; UDF at 40 t/ha has reduced soil J2 populations by around 95% in trials.
  • Biological: Pochonia chlamydosporia, Purpureocillium lilacinum and Pseudomonas fluorescens applied as soil drenches.
  • Chemical: spot applications of registered nematicides at planting and during the rest period of the bahar cycle.

See also: Pomegranate Bhagwa, Pomegranate Ahar Bahar Cycling, Pomegranate Anthracnose Bacterial Blight, Pomegranate Shade Net Canopy.

References

  1. Root-Knot Nematodes infecting Pomegranate. Agricultural Reviews, ARCC.
  2. Root Knot Nematode in Pomegranate (arid areas). MDPI Horticulturae.