VEGETABLE CROPS AND NEMATODES PROBLEM

VEGETABLE CROPS AND NEMATODES PROBLEM

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Introduction:

India has a diverse culture of horticultural crops including vegetables. Vegetables are rich and comparatively cheaper source of vitamins. Consumption of these items provides taste, palatability, fiber for digestion and increases appetite. As per dietician, daily requirement of vegetables is 75-125 g of green leafy vegetables, 85 g of other vegetables and 85 g of roots and tubers with other food. Vegetables are hosts to many of plant-parasitic nematodes (PPNs) capable of causing significant yield losses. Among PPNs, root-knot nematode (Meloidogyne spp.) is the most frequently observed genera in vegetable ecosystem. They are distributed worldwide over a wide range of geographical conditions, preferably more prevalent in tropical and sub-tropical climatic zones. In India, an average annual loss 19.6 % has been estimated due to PPNs. Once the root-knot nematode is established in a vegetable field, it is virtually impossible to eradicate. For the effective management in infested field, it is imperative to disturb the harmonious relationship between nematode and host plant through altering soil ecosystem. In addition to PPNs, many other pests can cause crop damage and yield losses which further enforce the development of an overall, integrated pest management (IPM) program, utilizing all available chemical and nonchemical means of reducing pest populations to sub-economic levels.

Important species: There are more species of root-knot nematode which are present in India but in Haryana, two species are of economic importance which causes considerable damage in vegetables and other horticultural crops.

  • Meloidogyne incognita
  • javanica

Distribution: Throughout the vegetable growing areas in Haryana.

Hosts: Very wide host range including virtually all vegetables like tomato, brinjal, okra, chilli, reddish, carrot and cucurbitaceous.

Disease caused: Root-knot disease of vegetables

Biology and life cycle: Root-knot nematode is sedentary endoparasite. The second stage juvenile (J2) is infective stage which penetrates the root tissue. The second stage juveniles start swelling and develop to third and fourth stages. Females is melon like shape, and lay 200-300 eggs on the root surface in a gelatinous matrix to form an egg mass. This nematode completes 7-8 generations in one year.

Damage symptoms:

  1. Above ground symptoms

Root-knot nematode infested plant may show yellowing, wilting during day time and stunted growth in patches which occurs mostly under field conditions.

  1. Below ground symptoms

Formation of knots or galls on the roots is the typical symptom caused by this nematode on various crops. The galls may vary in size and shape depending upon initial nematode population, species of the nematode, type of the plant etc. Under severe infestation, it also predisposes the attack of certain weak fungi and bacteria.

Fig: Root-knot nematode symptoms on various crops

: Root-knot nematode symptoms on various crops
: Root-knot nematode symptoms on various crops

Management

Although nematodes may be present and potentially causing damage, several management options will reduce the levels of nematodes to allow success when growing susceptible crops.

  1. 2-3 deep summer ploughings at 10-15 days interval during May/June.
  2. Rotations with onion, garlic and cereal crops.
  3. Grow root-knot nematode resistant variety- Hisar Lalit of tomato and Pusa Jwala of chilli.
  4. In okra, mix Trichoderma viride @ 2.5 kg/ha in the soil at the time of sowing.
  5. In bottle guard, apply 30 g neem cake at sowing spot and treat the seed with GD 35-47 Biotica @50 ml/acre to manage root-knot nematode.

6. In tomato nursery, apply neem cake @ 750 g/m2 one week before sowing in the soil followed by light irrigation.

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Article

Priyanka Duggal and Vinod Kumar

 

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