The need to produce horticultural produce for Indian markets and export purposes throughout the year, necessity to produce off-season vegetables under controlled conditions, intention to reduce pest and insect incidence, has led to adoption of poly house and protected cultivation across the Country.
Nematodes have become a major constraint in poly house cultivation, the major nematode being root knot nematode, Meloidogyne incognita.
This nematode causes characteristic galls in the roots resulting in damages and dislocation of xylem vessels which impair the movement of water and minerals.
The characteristic symptoms are stunted growth and formation of small and chlorotic leaves. The conditions such as lack of fans and foggers in such structures results in abnormal increase in humidity which inturn becomes congenial for nematode multiplication. Site on which the poly houses are erected has a history of solanaceous vegetables will contain inoculums of root knot nematode in soil which will multiply once the plants establish in poly house. Many times growers do not adopt soil solarisation/soil sanitation techniques and often opt to go for continuous planting of a single crop which again triggers root knot nematode.
Poly house growers are hence advised by the Nematologists of Tamil Nadu Agricultural University, Coimbatore to get their soil checked for presence of nematodes if any before confirming the site for erection of poly house structures which will reduce the risk of nematode menace after plant establishment. Seedlings purchased must be checked for galls if any (caused by nematodes) as many times seedlings themselves serve as carriers of nematodes into the polyhouse.
During summer months soil must be solarised by covering the soil (moistened) with white coloured polyethene sheets so as to enhance the humidity which will inturn kill the eggs and juveniles if any in the soil. Well decomposed compost has to be incorporated into the soil before ploughing to increase the beneficial microfauna. Nematode egg parasitic fungi such as Purpureocillium lilacinum and Pochonia chlamydosporia may be multiplied in well powdered moistened farm yard manure, kept in shade for two to three weeks and added into the soil for easy multiplication of the bioagent which inturn parasitizes the eggs of root knot nematode preventing them from hatching.
Marigold plants exude certain compounds which repel nematodes and growing them densely before the main crop will help in reduce nematode population considerably. Care should be taken to remove stubbles and decayed roots of previous crop before taking up sowing/ transplanting, as often the left out root materials act as inoculums for root knot nematode for the forth coming crop. Carbofuran 3G granules can be used initially to destroy nematodes which can thereafter be maintained at low levels by the measures suggested above, says Dr.K.Poornima, Professor of Nematology and Dr.S.Subramanium, Professor and Head of Department of Nematology, TNAU, Coimbatore.
Nematodes have become a major constraint in poly house cultivation, the major nematode being root knot nematode, Meloidogyne incognita.
This nematode causes characteristic galls in the roots resulting in damages and dislocation of xylem vessels which impair the movement of water and minerals.
The characteristic symptoms are stunted growth and formation of small and chlorotic leaves. The conditions such as lack of fans and foggers in such structures results in abnormal increase in humidity which inturn becomes congenial for nematode multiplication. Site on which the poly houses are erected has a history of solanaceous vegetables will contain inoculums of root knot nematode in soil which will multiply once the plants establish in poly house. Many times growers do not adopt soil solarisation/soil sanitation techniques and often opt to go for continuous planting of a single crop which again triggers root knot nematode.
Poly house growers are hence advised by the Nematologists of Tamil Nadu Agricultural University, Coimbatore to get their soil checked for presence of nematodes if any before confirming the site for erection of poly house structures which will reduce the risk of nematode menace after plant establishment. Seedlings purchased must be checked for galls if any (caused by nematodes) as many times seedlings themselves serve as carriers of nematodes into the polyhouse.
During summer months soil must be solarised by covering the soil (moistened) with white coloured polyethene sheets so as to enhance the humidity which will inturn kill the eggs and juveniles if any in the soil. Well decomposed compost has to be incorporated into the soil before ploughing to increase the beneficial microfauna. Nematode egg parasitic fungi such as Purpureocillium lilacinum and Pochonia chlamydosporia may be multiplied in well powdered moistened farm yard manure, kept in shade for two to three weeks and added into the soil for easy multiplication of the bioagent which inturn parasitizes the eggs of root knot nematode preventing them from hatching.
Marigold plants exude certain compounds which repel nematodes and growing them densely before the main crop will help in reduce nematode population considerably. Care should be taken to remove stubbles and decayed roots of previous crop before taking up sowing/ transplanting, as often the left out root materials act as inoculums for root knot nematode for the forth coming crop. Carbofuran 3G granules can be used initially to destroy nematodes which can thereafter be maintained at low levels by the measures suggested above, says Dr.K.Poornima, Professor of Nematology and Dr.S.Subramanium, Professor and Head of Department of Nematology, TNAU, Coimbatore.