Nematode management in protected cultivation

Nematode management in protected cultivation describes about existing practices of farmers and scientific integrated nematode management techniques along with IIHR package of practices.

1. NEMATODE MANAGEMENT IN PROTECTED CULTIVATION

2. nematodes Nematodes are microscopic, worm-like animals but not true micro-organisms as they have all the systems that higher animals possess, except the skeletal, circulatory and respiratory organs. They occur everywhere, except air . A handful of soil from anywhere has hundreds or even thousands of nematodes

3. The soil nematodes can be broadly classified into two groups – the free-living (microbial feeders, saprophytic and predators) and plant parasitic nematodes . Free-living nematodes inhabit all types of soils (being most abundant in organic soils). Some of them play crucial role in organic matter recycling. The plant parasitic nematodes dominate in soils having vegetation.

4. PPN s - Plant Parasitic nematodes

5. WHAT ACTUALLY NEMATODES DO IN PLANTS? The semi- endoparasitic and endoparasitic nematodes are considered most harmful They modify the conducting vessels (xylem and phloem cells) of plant tissues. They direct the flow of water and nutrients for their own feeding Thus partially blocking the flow of nutrition to plant system. Mostly, the feeder roots (fine branches) are destroyed compared to the main roots

6. 6. This is a continuous process leading to undersized “bare root system” devoid of fine rootlets 7. Consequently, the absorption of water and nutrients and their translocation to shoots are adversely affected . 8. Being obligate parasites, PPNs rarely kill their host plants 9. Instead, the plants are rendered weak, stunted , and give a pale appearance due to poor supply of nutrients. 10. However, they often pre-dispose plants to infection by pathogenic fungi and bacteria , leading to mortality or excessive damage.

7. Loss due to nematodes In India, on an average, a national loss of Rs. 21,068.73 millions has been estimated due to plant parasitic nematodes. An overall average annual yield loss in major horticultural crops due to nematodes goes up to 60% under protected cultivation. Crops grown throughout India are seriously infested with nematodes such as Meloidogyne incognita, M. javanica (root-knot nematodes) and Rotylenchulus reniformis (reniform nematode). Nematode problems on all these crops under protected conditions have assumed alarming proportions leading to huge crop losses (up to 80%) in selected crops.

8. Nematodes- the Serious Pests of Protected Cultivation!!!

9. Why? High day time temperature and relative humidity within the greenhouses and low tunnels General poor plant hygienic conditions inside and outside the greenhouses provide ideal conditions for the introduction and rapid multiplication of insects, fungal, viral bacterial and diseases caused by plant parasitic nematodes The proliferation rates of nematodes in poly house cultivation reached up to 10 to 30 folds more than in the open field cultivation . The population build up is very rapid in the poly houses and nematode population reaches 5 – 6 times of threshold levels within 18 - 24 months, making the poly house cultivation a wasteful exercise . (Hanafi & Papasolomontos , 1999; Greco & Esmenjaud , 2004).

10. PPN S Root‐knot nematodes ( Meloidogyne  spp.) Cyst nematodes ( Heterodera  and  Globodera  spp.) Root lesion nematodes ( Pratylenchus  spp.) Burrowing nematode  ( Radopholus similis ) Reniform nematode  ( Rotylenchulus reniformis ) Xiphinema index   (the only virus vector nematode) Foliar nematode ( Aphelenchoides fragariae , A. besseyi ) Burrowing nematode ( Radopholus similis ) Bulb and stem nematode ( Ditylenchus dipsaci )

11. Polyhouse crops are confronted with all categories of nematodes attacking roots Ectoparasites are invariably present and less damaging The focus is on endoparasites that are most damaging Generally, nematode distribution in open field conditions is patchy ; while in polyhouses , this is more or less uniform

12. Identifying nematode Attacked plants Most people judge if the plant gives a sick (pale/stunted) appearance, their impression is deficiency of nutrition or water stress That is true, but this situation could be due to nematode damage, as affected roots would not be able to uptake nutrients even if available abundantly in soil But many people do not uproot the plants to diagnose symptoms on the roots If only we uproot the sick plants and study the damage to roots, at least some important nematode diseases can be diagnosed.

13. SOURCES Source of Nematode Infection y Infested Soil- Yes y Infected planting material- Yes, sometimes only y Water- Sometimes Yes y Air- No y Seed- Sometimes Yes Source of Nematode Spread y Implements used in polyhouses y Footwear of workers y Agricultural machinery

14. Nematode Management in Protected Cultivation Systems

15. Farmers’ Perceptions and Practices Many polyhouse growers are aware about nematode problems This is mainly because of the high value crops cultivated in polyhouses where each and every plant is precious, remunerative that farmers can ill-afford to lose They are ready to invest anything to protect their plants Higher literacy rates among polyhouse growers is another factor for their concerns about nematode problems. Most farmers rely on pesticide dealers for nematode solutions, rarely seeking expert advice

16. Given below is a gist of what farmers generally practice for nematode management in polyhouses ; along with expert comments to dispel their perceptions.

17. NEMATODE MANAGEMENT– Scientifically

18. Nematode management is largely prophylactic or based on cultural and biological methods. These have to be initiated before planting / sowing time; however, it is nearly impossible to manage nematodes in standing crops.

19. 1. Construction of New Poly house/Net house – Mandatory Soil Testing for Nematodes Fields having a long history of vegetable cultivation should be completely avoided. Fields under cereal crops usually may not harbour nematodes that attack polyhouse crops. Ignorance of this particular precaution can lead to disastrous nematode infections in the first crop itself. It is strongly recommended that soil samples collected from proposed sites for the construction of new poly houses/net houses be compulsorily tested for nematode infestation.

20. Avoid the Sites for Construction of New Poly houses with History of Following Crops Major Root-Knot Nematode Susceptible Crops 1. Vegetable Crops: Tomato, Capsicum, Chilli, Brinjal, Carrot, Lady’s Finger (‘Bhindi’), gourds, melons etc. 2. Fruit Crops: Papaya, Grapes, Pomegranate, Banana, Guava etc. 3. Pulses and Oilseed Crops: Pigeon pea, Chickpea, Greengram , Blackgram , Groundnut etc. 4. Ornamental Crops: Gerbera, Carnation, Tuberose etc.

21. Sampling for Nematode Diagnosis Collection of soil samples for nematode assay from proposed site of new poly house/ net house or just before planting a new crop in the established poly house/net house a) Remove 2-3 cm upper layer of the soil with the help of a hand hoe (‘ khurpi ’/spade) b) Collect about 50 grams (a handful) soil up to a depth of 15-20 cm (subsample- Fig 1). c) Collect 10-20 such subsamples from one-hectare area in a zig-zag manner (Fig. 2) covering the whole field area.

22. d) Put all the subsamples in the same polythene bag (composite sample); the total weight should not be less than half kg and tie it with a rubber band. Keep the sample in another polythene bag. e) Write the sample details on a paper and keep it in between inner and outer polythene bag. f) Seal the outer bag; it is ready for dispatch to a nearest nematology lab for assay.

23. 2. Raising Nematode-Free Planting Material Seeds of varieties suitable for poly houses may be procured from reliable dealers only. The seedlings must be raised only in soil-less media Prepared in clean and sterilized plastic trays (or washed thoroughly with bleaching solution) by growers themselves, or procured directly from designated nurseries.

24. Special care should be taken that the soil-less medium should not come in contact with soil, and that the trays should also be stacked on raised structures.

25. No farm yard manure or vermicompost may be added in the nursery medium in spite of the fact that soil media (cocopeat, vermiculite or perlite) do not contain any nutrients for the plant. Only water soluble fertilizers may be used. Irrigation of nursery trays should be done only with very clean and algae-free water.

26. 3. Monitoring Nematode Population in Existing Poly house/Net house It is always advisable to get the soil tested for nematodes before planting a crop. Based on the nematode population in the soil at the time of planting a new crop, it is possible to predict the likelihood of crop losses. Prepare the field as is normally done for new crop, collect the soil sample and get it tested for nematodes. Based on the recommendations, follow the nematode management protocols, if necessary. Even if the poly house/net house has no history of nematode infection, the soil testing is always preferable.

27. 4. Removal of Roots from Previous Crop Roots harbour nematode eggs, and each root gall contains hundreds of nematode eggs. Old galls coalesce that contain thousands of eggs inside. After the crop is over, in spite of pulling the plants along with roots, some galls detach from the roots and the nematode juveniles emerge from the leftover roots in the soil. These nematode juveniles are ready to infect the new crop.

28. Therefore, it is strongly recommended that the roots of previous crop should be removed as much as possible. Digging out the finer roots is most essential. Such removed roots should be piled in a heap outside, dried and burnt (at a safe distance away from poly houses). This single practice can remove 80-90% of nematode inoculum from the soil.

29. 5. Summer Solarization Every year, during peak summer (May-June), after the crop is over and removal of leftover roots is complete, the field should be ploughed thoroughly, leveled and watered lightly just to dampen the soil. The soil surface should be covered with thin (25 µm) transparent polythene sheet. The edges should be overlapped and sealed properly.

30. The whole polyhouse should be sealed by dropping the polythene curtains on all sides. Do not open the polyhouse for a minimum 2-3 weeks. This practice can coincide with preparation of nursery in the meantime, besides preparing the multiplication of bio-agents outside. Soil solarization singly is so effective that if done meticulously, there may not be any necessity of using chemical pesticides.

31. 6. Organic Amendments Fortified with Bio-agents Nematologists at IIHR, Bengaluru standardized successful management strategies of nematodes and other disease complex using bio-pesticides like Paecilomyces lilacinus , Pochonia chlamydosporia , Trichoderma harzianum , T. viride and Pseudomonas fluorescens . Farmers who adopted IIHR technology reduced the use of agro - chemicals to 40 to 45% and obtained 30 to 35% increased yields in capsicum, gerbera and carnations.

32. Select a shady, cool and covered place for stacking well rotten FYM or Vermicompost or both. One ton of FYM (one big tractor trolley) is sufficient for one-acre poly house. Procure bio-control agents like Trichoderma harzianum or T. viride and Pseudomonas fluorescens from a reliable source. The efficacy of bio-agents is important in terms of no. of propagules (CFU-Colony Forming Units) present per cc/g in the bio-agent culture being used for fortification of FYM. Trichoderma harzianum or T. viride should have a minimum of 2x10 8 CFUs per cc , while P. fluorescens should contain 2x10 12 CFU per cc.

33. PROCESS- ENRICHMENT OF FYM Sprinkle/pour the bio-agent on the heap of powdered FYM at the rate of 2 kg/2 L per ton. This should be followed by thorough mixing of the bio-agent in FYM. Moisten the heap by sprinkling water and fully cover it with banana, coconut leaves or chaff that allows aeration. The FYM should not come in contact with soil, and well protected from sunlight and rains. Mix the heap once in a week, followed by moistening and covering again for 3-4 weeks, till the time solarization is going on and seedlings are being raised in the nursery trays concomitantly.

34. Steps Involved in Fortification / Enrichment of FYM using Bio-Agents

35. Once the solarization process is over, remove the polythene sheets from poly house, prepare the beds and mix the bio-agent fortified FYM uniformly over the beds in top soil. The quantity would vary depending upon the overall nutrient status of poly house soil. Trichoderma and Pseudomonas are general bio-agents that improve the plant health and have broad spectrum activity, including against nematodes. However, should there be specific nematode problems, bio-agents like Purpureocillium lilacinum ( Paecilomyces lilacinus ) or Pochonia chlamydosporia can be procured and multiplied in the same way in FYM using similar dosage levels as mentioned above. Neem cake powder @ 50-100 g/m 2 of planting bed may be mixed on the top layer about 7-10 days before seeding/transplanting.

36. Process of Enrichment of neem/ pongamia / mahua cake 1 ton of neem/ pongamia / mahua cake has to be enriched by mixing with 2 kg of each of Pseudomonas fluorescens + Trichoderma harzianum + Paecilomyces lilacinus . It has to be covered with mulch and optimum moisture of 25 - 30% has to be maintained for a period of 15 days. Once in a week thoroughly mix the neem cake for maximum multiplication and homogenous spread of the microorganisms in the entire lot of neem cake.

37. Process of Enrichment of vermicompost 1 ton of vermicompost has to be enriched by mixing with 2 kg of each of Pseudomonas fluorescens + Trichoderma harzianum + Paecilomyces lilacinus . It has to be covered with mulch and optimum moisture of 25 - 30% has to be maintained for a period of 15 days. Once in a week thoroughly mix the vermicompost for maximum multiplication and homogenous spread of the microorganisms in the entire lot of vermicompost.

38. 7. Crop Rotation and antagonistic crop Crops which invite nematode problems must be rotated with some other non- host crops. Once nematode problem inside poly house is identified, the immediate next crop must be changed. Also antagonistic crop like Marigold can be planted randomly in beds to reduce nematode infestation. Antagonists Crotolaria juncea (Green manure) crop can be raised and incorporated into soil before cropping.

39. Asparagus, pangola grass, neem, castor bean, and marigold produce substances in their roots that are toxic to at least one or more kinds of nematodes. Marigolds are known to be particularly effective against root-knot nematode. Marigold  roots release the chemical alpha-terthienyl

40. 8. Chemical Nematicides We suggest that chemical application may be done only when absolutely necessary, under conditions of very high initial nematode population. Carbofuran is a granular nematicide that can be applied in soil at the time of seeding/transplanting @ 1-2 kg a.i. /ha. However, carbofuran does not give the desired result for long durations under polyhouse conditions as the nematodes tend to rebuild their population within 2-3 months of its use.

41. Soil fumigation can be made by the use of Methyl Bromide, but it is banned. So Metham Sodium, Basamid , Dazomet and Cador are used now. Oxamyl , fenamiphos , cadusafos and ethoprop are the most popular nonfumigant nematicides. The post plant application of oxamyl was useful after preplant application of 1,3 D/ metham sodium under black polythene mulch. Metham sodium was applied by drip and 1,3D along with Chloropicrin were applied one month before planting significantly reduces nematode population. In view of long-pending demands, several pesticide companies have developed products based on chemicals like fluopyram , fluensulfone etc. having nematicidal properties.

42. SOIL FUMIGATION

43. 9. General Sanitation in and around Greenhouse A strict routine of removal of weeds in and around polyhouses should be followed as they provide safety against during the off-season. Apart from crop rotation inside the greenhouse, cultivation of nematode susceptible crops should be avoided in the vicinity of greenhouses.

44. 10. Grafting WITH RESISTANT ROOT STOCKS Plants are joined together so that they grow as one plant The below ground portion of the plant i.e. , ‘rootstock’ is chosen for its ability to resist or tolerate soil-borne diseases or abiotic stresses and the above-ground portion ‘scion’ is taken based on its agronomic traits. Major advantages of grafting include disease or nematode resistance, stress tolerance or increased productivity. Nematode resistant root-stocks claimed by some private nurseries may be confirmed with experts before adoption.

45. 11. Soil-less Cultivation Soil-less cultivation is a process of growing plants (without soil) in water containing dissolved nutrients, especially practised in greenhouses with specialized structures having controlled environment. It is free from weeds, nematodes and soil-borne diseases due to aseptic processing . It is an advanced and capital intensive method. Coco- peat is widely used

46. Soil-less cultures fall into three general categories: i ) Solid substrate culture: where different media, all without soil are used. ii) Hydroponics: In this system, plants are supported in water soluble nutrient media iii) Aeroponics: In this system, plant roots are suspended in controlled condition chambers and supplied soluble nutrient media through sprays, atomization etc.

47. Package of practices given by iihr Land should be thoroughly ploughed and soil should be brought to fine tilth. Before preparation of the beds in the poly-house, incorporate 20 tons of FYM enriched with the bio-pesticides in the soil. Raised beds made with size according to the requirement and the type of crop. Add recommended doses of fertilizers. Also add carbofuran or phorate @ 50g/ sq.m + 200g neem/ pongamia / mahua cake enriched by bio-pesticides per sq. m.

48. Further incorporate bio-pesticide enriched FYM@ 2kg/sq. m or biopesticides enriched vermicompost @ 500g/ sq.m in top 18 cm of soil in the beds. Water the beds for 7-10 days for proper decomposition of these organic materials. It is possible that farmers would not have prepared beds initially as mentioned above and they observe the infestation of nematodes, soil borne pathogenic fungi and bacteria on the crops. Then the following steps for the management of nematodes, soil borne pathogenic fungi and bacteria need to be taken.

49. Application of the bio-pesticides to a standing crop- iihr Step 1: Soil application: Apply 100 g of neem / pongamia / mahua cake or 250 g of vermicompost enriched with Pseudomonas fluorescens + Trichoderma harzianum + Paecilomyces lilacinus on 1 sq. m. beds or around the rhizosphere of the plants.

50. Step 2: Spraying: The organic formulation containing Pseudomonas fluorescens and Trichoderma harzianum has to be sprayed on the plants at regular intervals of 20 days at a dosage of 5g/ lit or 5ml/ lit. Alternately, take 20 kg of neem/ pongamia / mahua cake enriched in the above mentioned manner and mix it in 200 litres of water, leave it for a period of 2-3 days. Filter this suspension and use it for spraying by mixing 250ml of suspension in 1 lit. of water at regular interval of 20 days.

51. Step 3: Drenching or application through drip irrigation system: The IIHR patented organic formulation has to be given through drip/ by drenching @ 5g/ lit or 5ml/ lit. at regular interval of 20 days. Alternately, take 20 kg of neem/ pongamia / mahua cake enriched in the above mentioned manner and mix it in 200 litres of water, leave it for a period of 2-3 days. Filter this suspension and use it for drenching at regular interval of 20 days. By following all these methods farmers can get significant increase in the yield of the crops and the cost benefit ratio will be above 1: 3.

52. NEMATODES IN COMMERCIAL CUT FLOWERS WITH MANAGEMENT

53. ROSE Root knot nematode( Meloidogyne incognita): Formation of Root galls Symptom of malnutrition, reduced shoot growth, chlorotic leaves Management: Deep summer ploughing, soil fumigation with Dichlorvos Application of Nemagon (10-12 l/ha) along with irrigation

54. Root lesion nematode ( Pratylenchus vulnus and Pratylenchus penetrans ): Cause root decay Stuntung of growth Chlorotic leaves Management: Application of Nemagon Soil fumigation with Dichlorovos or Carbon disulphide

55. gerbera M. incognita infection makes the plants highly susceptible for the attack of Fusarium oxsporum f.sp . dianthi . Phytophthora parasitica + M. incognita interact to produce a disease complex in gerbera leading to reduction in the yield around 40 to 60 %. Management same as in rose.

56. Carnation Carnation is a host to about 21 nematodes The most important ones are Cricomemoides curvatum , Cricomemoides xeroplex and Meloidogyne incognita. Nematodes cause reduced root system, stunted shoot growth and reduction in the number of blooms Nematodes can be eliminated by growing plants in fumigated soil Application of Furadon . Aldicarp or nemaphos @ 10g/m 2 can control nematodes.

57. Foliar nematode ( Aphelenchoides besseyi )  in Tuberose Infected flower stalk initially appears rough, stalk becomes crinkled, stunted and finally distorted and in severe cases flower buds failed to bloom . Brown streaks appear on leaf bracts and petals and subsequently develop into rusty brown spots. The severely infected flower stalk becomes rotten and brittle over drying, even gets blind and the number of flowers per stalk is also reduced.

58. Nematode management approaches IN TUBEROSE: Pre- soaking of tuberose bulbs in plain water or in neem-seed-kernel-extract (NSKE 4%) for overnight followed by dipping in monocrotophos 36SL at 500-700ppm for 4-6 hours. After sprouting, three to four sprayings with monocrotophos 36SL at 500ppm at 15 to 20 days interval is needed. In the second and third year crop, same spraying for 3-4 times with monocrotophos 36SL at 500ppm at 15 to 20 days interval should start from April-May onward to reduce the nematode infestation. Field sanitation is most essential for reducing infestation. Infested plant parts should be burnt or buried into the soil. Grow nematode tolerant tuberose cultivars, Prajwal and Shringar (Khan & Ghosh, 2007) Growing tuberose away from rice field is encouraged to avoid contamination of tuberose field. 

59. Chrysanthemum Meloidoyne incognita- Root knot nematode Pratylechus penetrans - Root lesion nematode Aphelenchoides ritzemabosi - Foliar/ leaf nematode Control: Use pasteurized or fumigated soil for nursery and main field Use nematode free planting material Sterilise soil before planting Maintain proper sanitation Apply carbofuran or phorate @ 50 g/sq. m. Follow IIHR package of practices

60. cROSSANDRA

61. PLANT PARASITIC NEMATODES ASSOCIATED WITH SOME IMPORTANT COMMERCIAL FLOWERS Nibedita Borgohain (Journal of Biosciences, India- 2016) In India, highly valued commercial flowers such as asiatic lily, carnation, chrysanthemum, gerbera, gladiolus rose, tuberose etc. Among various nematodes identified the most devastating nematode genera affecting flowers are Meloidogyne, Aphelenchoides , Ditylenchus, and Pratylenchus .

62. ROOT KNOT NEMATODE IN FLOWER CROPS

63. Foliar nematode Aphelenchoides spp.: Foliar nematodes are one of the most important nematode pests which attack ornamental plants, especially chrysanthemum. These nematodes attack leaves, buds and other soft above ground plant parts rather than roots in temperate regions of the world and is always highly damaging in wet and cool seasons. PLANT PARASITIC NEMATODES ASSOCIATED WITH SOME IMPORTANT COMMERCIAL FLOWERS:

64. SYMPTOMS: Initial symptom is a chlorotic linear lesion, which latter become brown or necrotic. Most characteristic symptom of the nematode infestation is the vein –limited necrotic symptom. Curling, twisting and stunted growth of newly emerge stems. Affected tissue turns pale green, then yellow and eventually brown.

65. Root-knot nematode Meloidogyne spp : It is a major disease in most of ornamental crops grown in India. The use of infested planting materials is a important source of spread of this disease in the subcontinent. SYMPTOMS: a. Generally infected plants show stunted growth and yellowing and chlorosis of foliage. b. On underground parts, gall and necrosis develops especially in chrysanthemum and carnation c. In tuberose the symptoms are exemplified by stunting, yellowing and drying up of leaves and rotting of bulbs. d. In gladiolus heavy root galling can be seen accompanied by yellowing of leaves which subsequently lead to stunted growth. e. Infected gerbera plants show the symptom of tip drying leading to die back.

66. Burrowing nematode Radopholus similis : SYMPTOMS: a. Radopholus similis cause extensive decay of root and rhizomes, stunting and chlorosis and eventually decline of plant. b. The infected plant show reduced number and size of flowers and shorth= ened the productive life of planting

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