Nematology

1. Introduction with summary of achievements

The project was implemented at Assam Agricultural University on 10.12.1977.At that time the title of the project was “All India Coordinated Research Project on Nematode Pests and their Control.” From April 1 of 1979, the title of the project was changed to “All India Coordinated Research Project on Plant Parasitic Nematodes with Integrated Approach for their Control.” Previously, the project was run under the department of Zoology and Entomology as there was no separate department of Nematology. In 1988 a separate department of Nematology was established and from then onwards, it is running under the department of Nematology.

The study of nematode problems started at Assam only after the introduction of the project. Many important nematode pests of different crops were identified from the continuous survey programmes and their control measures were recommended time to time. In addition to nematodes problems, the project is working on i. Identification of fungal and bacterial endophytes and their efficacy against selected nematode pest ii. Isolation and identification of entomopathogenic nematodes and their efficacy against insect pests iii. Community structure and impact of plant parasitic nematodes in need based cropping systems followed and nutrient supply systems in cereal based cropping systems etc. iv. Pest risk analysis of major nematode pests in the state.

The salient achievements of the project are summarized below-

1. Different important nematode pests are identified viz., 1. Meloidogyne incognita in vegetables, pulses, jute, fruit crops etc. 2. Meloidogyne graminicola in rice 3. Ditylenchus angustus in deep water rice 4. Tylenchulus semipenetrans in citrus 5. Rotylenchulus reniformis in vegetables, bananas etc.

2. Identification of hot spots of important nematodes and their mapping

3. Estimation of yield loss in different crops by different nematodes like-

4. Identification of interactions of nematodes with bacteria like M.incognita and Pseudomonas solanacearum in brinjal, tomato

5. Identification of nematode- fungus complex like M.incognita and Rhizoctonia solani in black gram and green gram

6. Identification and management of M.incognita – Ralstonia solanacerarum complex in jute

7. Management of Ditylenchus angustus (Ufra disease) through burning of stubbles, use of chemicals and ufra resistant variety ‘Basudev’ and inclusion in POP

8. Management of M.incognita problem in black gram and green gram by seed treatment with chemicals carbosulfan 25 SD and bioagents Pseudomonus fluorescens and Trichoderma viride and inclusion in POP

9. Management of M.incognita in vegetables by application of organic amendments and chemicals and inclusion in POP

10. Management of M. graminicola in rice through chemical carbofuran and biocontrol agent P.fluorescens and inclusion in POP

11. Management of rice root nematode Hirschmanniella oryzae through chemical carbofuran and cartap hydrochloride

12. Management of phytonematodes in okra by crop rotation viz., okra-rice-fellow

13. Management of M. incognita in pulses through intercropping with non-host crop like groundnut and mustard

14. Management of M. incognita and M. incognita-Ralstonia solanacearum complex in jute by chemical carbofuran and biocontrol agent P. fluorescens

15. Identification of sources of resistance of different crops against nematode pests through screening of lines/germplasm/varieties

16. Identification of entomopathogenic nematode species viz., Steinernematami, S.abbasi, S.ceratophorum, S.aciari, S. kusidai, Heterorhbditis bacteriophora, and their in vitro and in vivo studies against insect pest

17. Identification of bacterial a endophytes viz., Fifteen endophytic bacteria were isolated from the tomato leaf and stem, out of which eight were identified using molecular tools as, Bacillus altitudinis, Bacillus marisflav, Microbacterium arborescens , Pseudomonu sflourescens, Exiguobacterium indicum,, Macrobacterium paraoxydans , Alcaligenes faecalis  and Escherichia coli .The isolates were evaluated for their efficacy against second stage juvenile of M. incognita in vitro and results showed that all the eight endophytes exhibited mortality of the second stage juvenile of M. incognita; however Bacillus marisflavi and Pseudomonus flourescens exhibited the best result.

18. Demonstration of technologies developed at farmers field

19. Organization of Nematode Awareness Programme and training on nematode pests management

 2. Varieties/Hybrids released : NIL

 3. Products, Farm machines/equipment, vaccines, process etc. developed, commercialized or licensed : NIL

 4. Crop management Package of Practices developed and recommended (included in POP of state Govt.) and are being used on a larger scale by farmers (Year wise):

 Technologies recommended and included in Package of Practices-

 5. Number of entries tested in AICRP trials (Year wise)

6. Productivity and Production during last 5 decades (1970-2020) – Commodity and

decade wise : Does not arise

 7. Milestone varieties/technologies and their impact on Production and Productivity, Socio- economic status of farmers thereof

  i. Application of carbofuran 3G in different crops against nematode pests-

 Among the plant parasitic nematodes, root knot nematode species Meloidogyne incognita in vegetables, pulses, fruit crops etc. and M. graminicola are very serious in Assam. Almost all the varieties of vegetables and pulses are prone to the attack of root knot nematode infestation. After the implementation of the project, various research programmes were carried out on the management of this important pest. Carbofuran was found very effective in managing this nematode and subsequently recommended and included in PoP of the state. In rice, particularly in direct seeded upland rice (Ahu rice) and in nursery, M. graminicola is a serious pest in the state. Against this pest also, carbofuran was recommended and included in PoP. The farmers of the state accepted this technology and they could get enhanced yield up to 25% in vegetables and rice.

ii. Burning of stubbles of deep water rice and application of carbofuran to manage ufra

disease-

Ufra disease, caused by Ditylenchus angustus is very serious in few pockets of Assam where deep water rice is practiced. Deep water rice is practiced in low land situation where other rice cannot be grown due to flooded situation. Deep water rice is attacked by this nematode and in serious condition there is 100% yield loss. During 1980and 1990s, this problem was very serious in Lakhimpur, Dhemaji, Jorhat and other districts where deep water rice was practiced. From the experiments it was found that the nematode inoculum is perpetuated in left over stubbles after harvesting in the field. So burning of stubbles and application of carbofuran @30kg/ha at the time of sowing was found very effective and recommended and included in PoP. The deep water rice growing farmers practice these technologies and effectively manage the problem. The yield of deep water rice is very low (1-2 ton/ha) and if ufra is occurred farmers get hardly any yield. After following these technologies, the farmers get yield up to 2 ton/ha. As the deep water rice growing farmers solely depend on yield of this rice, the technology is very popular among the farmers.

iii. Application of organic amendments in vegetables against M.incognita

Most of the vegetables are infested by M. incognita. Organic amendmends like neem cake, mustard cake, saw dust etc are found effective. These organic amendments are recommended and included in PoP. The commercial vegetable growers follow this practice along with application of carbofuran. As the application of organic amendments have added advantage in increasing soil fertility besides controlling nematodes, it is

To survey and isolate the endophytes occurring in banana (Musa spp.) in Assam

A total of 164 soil and plant samples were collected from 11 districts of Assam viz. Golaghat (12), Jorhat (19), Sivsagar (15), Nagaon (9), Marigaon (11), Kamrup (11), Goalpara (15), Dibrugarah (18), Tinsukia (21), Dhemaji (20) and Lakhimpur (13). The soil samples were processed through Cobb’s modified sieving and decanting method for isolation of plant parasitic nematode population. Thereafter, the nematodes were identified though morphological character. The maximum frequency (100%) of occurrence of M. incognita was recorded in Golaghat district and minimum was recorded in the Dhemaji district. The maximum number and density of M. incognita was recorded in the Nagaon district while minimum number and density was recorded in the Dhemaji district of Assam.

The molecular identification of root knot nematode was done by using species-specific primers.

Out off 143 soil and plant samples collected from 7 districts (Golaghat, Jorhat, Sivsagar, Nagaon, Marigaon, Kamrup and Goalpara) of Assam, a total of 9 isolates comprising 5 Fungal and 4 Bacterial, have been isolated and sent to TNAU centre for in-vitro efficacy test against Meloidogyne incognita.

To screen the endophytes under pot culture studies against root knot nematode, Meloidogyne incognita in Banana

A total of 92 endophytes (Fungi: 55 and Bacteria: 37) were isolated from banana roots and were screened by TNAU Center, Coimbatore for their in-vitro efficacy against M. incognita. From this study, 3 bacterial endophytes viz., Lysinibacillus fusiformis(BC1), Klebsiella oxytoca (EB8), Pseudomonas geniculata (EB4) and 3 fungal endphytes viz.,Fusarium oxysporum (B10), F. oxysporum (B40) and F. oxysporum (B41) were found to be promising and were selected for pot experiment to know the performances under Assam conditions.

Among the endophytes tested, bacterial endophytes were found to be more effective than the fungal ones in respect of reducing the nematode multiplication and increasing the plant growth parameters and defense enzymes and total phenol. The bacterial endophytes, Pseudomonas geniculata (EB4) and Lysinibacillus fusiformis (BC1) were found to be more effective against Meloidogyne incognita than rest of the endophytes.

To develop the consortium of liquid formulation of promising endophytes

Liquid formulations (Consortium of P. geniculata and L. fusiformis) were prepared using BHI broth media by adding additives, adjuvants and surfactants in different combinations. Shelf life studies were conducted and found to be 180 days (6 months).

To evaluate bio-formulations against root knot nematode in banana under pot and field condition in Assam

Pot experiments

a. To evaluate bio-formulations against root knot nematode in banana (suckers) under pot condition

Paring and dipping with microbial consortia (L. fusiformis and P. geniculata) as liquid @20ml / sucker yielded maximum plant growth parameters viz., shoot length, shoot weight, root length, root weight and pseduostem girth of banana and reduced nematode multiplication viz., number galls per root system and final nematode population in soil.

b. To evaluate bio-formulations against root knot nematode in banana (tissue culture) under pot condition

Soil application of microbial consortium (L. fusiformis and P. geniculata) as liquid@20 ml / plant yielded maximum plant growth parameters viz., shoot length, shoot weight, root length, root weight and pseduostem girth of banana and reduced the nematode multiplication viz., number galls per root system and final nematode population in soil.

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Principal Investigator : Dr (Mrs) Aparajita Borah, Professor, Department of
Nematology, AAU., Jorhat

 Sanction No
& Date : F.No
2-18/2000-PP Dated the 28^th Octo,2002

Sanctioned budget : 10,28,297.00

Duration : 3 years

Year : 2003-2006

Objectives :

1.Survey of
native fungi from the rhizosphere of pulse crops of different parts of Assam.

2. Studies on
the factors influencing the efficacy of VAM in checking M. incognita in blackgram/greengram

3. Comparative
efficacy of VAM fungi with nematicides and organic amendments against root-knot
nematode on blackgram and greengram.

Objective 1. Survey of native VAM fungi
from the rhizosphere of pulse crops of different parts of Assam

All total 296 soils and root samples were collected
from the rhizosphere of different pulse crops covering 20 districts of Assam.
Collected soil samples were processed and VAM fungi were isolated and
identified as Glomus, Gigaspora, Scutelospora, Acaulospora.
Among them, Glomus and Gigaspora were found to be most common.
However, Glomus fasciculatum was
found to be the most prevalent species in all the localities surveyed.

Objective2.
Studies on the factors influencing the efficacy of VAM in checking Meloidogyne incognita in
blackgram/greengram

Root-knot nematode reproduction was found to be
minimum in sandy loam soil as compared to other types of soil (loam, clay loam,
clay, silt loam) when VAM fungus Glomus fasciculatum
was inoculated along with M. incognita.
The plant growth parameters of green gram were found to be reduced in the
treatment receiving nematode alone in all types of soil, but increased growth
was observed when soil was supplemented with VAM fungus. VAM spore population
in soil and mycorrhizal colonization in root were found higher in coarse
textured soil as compared to clay soil and same trend of results were also
observed in case of plant growth parameters of greengram.

            Lowest plant growth parameters of
blackgram were observed at 20% moisture level when plants were simultaneously
inoculated with Glomus fasciculatum
and Meloidogyne incognita.  Increased plant growth parameters were
observed from 40 to 70% moisture level with maximum being at 70% when VAM and
root-knot nematode inoculated simultaneously. Decline in growth was observed
from 80 to 100% moisture level. A negative correlation was observed between the
moisture level and VAM spore population and mycorrhizal colonization in root.
High spore cunt and mycorrhizal root colonization was observed at 30% moisture
level, where as 100% moisture level recorded low spore count and colonization.
A positive correlation was observed between moisture level and final nematode
population in soil, number of galls and eggmasses per root system.

            As compared to that of the treatment
with recommended level and ¾ of recommended level of SSP, the treatment with ½
of recommended level of SSP with VAM fungus was found to be more effective in
reducing the number of galls and eggmasses per root system and root-knot
nematode population in soil Likewise as compared to that of recommended level
and ¾ of recommended level of SSP, the treatment with ½  of recommended  level of SSP along with inoculation of VAM
and root-knot nematode recorded increase plant growth parameters of greengram,
VAM spore population in soil and mycorrhizal root colonization.

Objective3:
Comparative efficacy of VAM fungi with nematicides and organic amendments
against root-knot nematode on blackgram and greengram

Efficacy of VAM fungus, Glomus fasciculatum in comparison with neem cake and carbofuran3G
against root-knot nematode, Meloidogyne
incognita on black gram and green gram was studied under micro plot and
field condition. In both the condition, the treatment with VAM was found to be
more effective in increasing the yield and plant growth parameters as compared
to the treatment with neem cake and carbofuran3G and maximum being in the
treatment with VAM at higher dose (1000spores/m²). Maximum reduction
of number of galls, eggmasses and final nematode population in soil was
recorded in the treatment with carbofuran3G @ 2kg a.i/ha followed by carbofuran3G
@ 1kg a.i/ha and VAM @ 1000spores.

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