Disease:Foot rot/Quick wilt/Phytophthora rot

Phytophthora capsici

This is the most destructive and widespread disease of pepper in Kerala.

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  • Disease 1
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  • disease 11
  • disease 12
  • disease 13
  • disease 14
  • disease 15
  • disease 16

Symptoms

  • This fungal pathogen affects all parts of the plant- roots, stem, leaves and berries.
  • During rainy season the tender leaves and succulent shoot tips of freshly emerging runner shoots trailing on the soil turn black when infected.
  • The disease spreads to the entire vine, from these infected runner shoots and leaves, during intermittent showers due to rain splash.
  • The branches break up at nodes and the entire vine collapses within a month . This is the most destructive stage of the disease and is commonly known as "quick wilt" or "foot rot".
  • If the damage is confined to the feeder roots, the expression of symptoms is delayed till the cessation of rain and the vine starts showing declining symptoms such as yellowing, wilting, defoliation and drying up of a part of the vine.
  • Foliar infection usually starts on very young leaves with characteristic brown to black colour with fimbriate margin.
  • On mature leaves infected area produces concentric zonations with grayish centre.
  • Foliar infection leads to varying degrees of defoliation.
  • Infections are also observed on spikes as brownish patches resulting in their shedding.

Epidemiology

The disease consists of two phases viz. aerial phase and soil phase. This fungus remains dormant in the soil during dry season and gets activated during rainy season as the soil moisture builds up. The disease spreads through infected planting materials, zoospores in soil water; rain splashes; root contact between healthy and infected vines, contaminated farm implements, movement of personnel, animals, etc. Termites and slugs also act as passive carriers of the inoculum. Generally disease spreads in a centrifugal pattern.

The foliar infection occurs mainly through splash dispersal. Foliar infection leads to different degrees of leaf and branch shedding depending on the severity of the disease. However, foliar infection will not lead to death of the vines but it debilitates the vine. The disease is generally noticed during June to September coinciding with the South -West monsoon. Low temperature of 22.7- 29.80C, short duration sunshine hours, high rainfall (15.8-23.0 mm/day) and RH of 81-99% favours the incidence of the disease.

Procedure for Observation

Foliar infection starts immediately after the first few monsoon showers on runner shoots at the base of the vine or on tender leaves at the lower region of the bush.Randomly select 100 keaves and calculate the % infection mild 1% moderate 5% serve >5%. Also look for the collar and other symptoms

ETL

  • If foliar symptoms are noticed on the newly emerging shoots, especially on runner shoots start control measures.
  • If the yellowing symptoms are observed during the summer season on more than 5% of the plants, management practices are to be followed on all plants immediately after the first monsoon shower.
  • Total replanting has to be undertaken where the mortality is 50% and above.
  • Where the mortality is below 50% plant protection measures are to be adopted on all plants.

    • Control Measures

  • The disease can be controlled by adopting integrated disease management strategies.
  • Planting material must be collected from disease free gardens and the nursery should be raised preferably in solarized soil.
  • Gap filling or replanting should be taken up only after a period of one year IISR-Sakthi and IISR-Thevam exhibit tolerance against foot rot. Plant these varieties when foot rot is endemic
  • Restrict the movement of animals and personnel from infected to healthy gardens.The freshly emerging runner shoots should not be allowed to trail on the ground.They must either be tied back to the standard or pruned off.
  • Reduced humidity and presence of sunlight reduces the intensity of leaf infection.
  • Apply 1 kg lime and 2 kg neem cake per standard per year as pre monsoon dose.
  • After the receipt of a few monsoon showers (May-June), all the vines are to be drenched at a radius of 45-50 cm with copper oxychloride 0.2% @ 5-10 liters/ vine. A foliar spray with Bordeaux mixture 1% is also to be given.
  • Drenching and spraying are to be repeated once again during August-September. A third round of drenching may be given during October if the monsoon is prolonged.
  • Do not use copper fungicides if the garden is protected with biocontrol agent as they are not compatible.
  • Inoculate the pepper vines with native arbuscular mycorrhizal fungi, Trichoderma and Pseudomonas fluorescens at the time of planting in the nursery and main field.
  • Mass multiply Trichoderma as enriched organic manure.