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Open Access
BIO EFFICACY OF NATIVE ENTOMOPATHOGENIC NEMATODES AGAINST MAJOR INSECT PESTS OF CRUCIFEROUS CROPS IN ASSAM
(2023) BHARATH, AMURI; Bhagawati, Bhabesh
A survey was conducted during the year 2020-2022 for isolation of entomopathogenic nematodes (EPNs) in cruciferous and vegetable growing areas of Jorhat district of Assam from 7 locations viz., Experimental Farm, Dept. of Horticulture, ICR Farm, AAU, Jorhat, Tea Plantations, AAU, Jorhat, Nemati Ghat, Moran Gaon, Titabor and 7 different isolates of EPN were recovered with 3.50 percent frequency of occurrence. Based on morphological and morphometric studies the isolates were identified to be Oscheius chongmingensis (EPN 1and 2), Heterorhabditis indica (EPN 3, 4and 5) and H. bacteriophora (EPN 6 and 7). Further, molecular characterization was done by amplification of ITS region of 5.8s mtDNA. The sequences of genus Heterorhabditis and Oscheius isolates were subjected to BLAST at NCBI and on the basis of aligned sequences, the isolates were identified to be Heterorhabditis indica, H. bacteriophora and Oscheius chongmingensis by using construction of phylogentic tree in MEGA 11.00. Efficacy of Oscheius chongmingensis, Heterorhabditis indica and H. bacteriophora were tested against Diamond backmoth (Plutella xylostella) and Cabbage butterfly (Pieris brassicae) under in-vitro conditions with six different concentrations of infective juveniles (IJs). With the increase in the concentration of IJs and with time of exposure, there was a corresponding increase in the mortality of the insect larvae. Heterorhabditis indica and H. bacteriophora showed 100 per cent mortality of P. xylostella and P. brassicae at 96 h of exposure with highest concentration of IJs/larva (i.e. 300 IJs/larva) as compared to O. chongmingensis (50.00 % mortality). The LD50 values of both the EPNs decreased when exposure period was increased. A pot experiment was also conducted to study the efficacy of two best EPNs viz. H. indica and H. bacteriophora against P. xylostella taking different doses viz. 200, 400 and 600 IJs/ pot with another treatment with water as control. H. indica exhibited maximum mortality at 600IJs after 72hrs of exposure and was found to be at par with the treatment with H. bacteriophora. The effective EPN species has to be further tested under filed conditions to identify the proper doses and method of delivery.
Open Access
MANAGEMENT OF Meloidogyne incognita IN TOMATO THROUGH GRAFTING
(2023) Das, Nikita; Bhagawati, B.
An attempt was made for the management of Meloidogyne incognita in tomato through grafting. Twelve Solanum species were screened against the M. incognita. Of these, S. torvum and S. lycopersicum cv. Hisar Lalit showed resistant reactions against M. incognita whereas S. viarum showed susceptible reaction against M. incognita and the remaining species showed highly susceptible reactions against M. incognita. S. torvum and S. lycopersicum cv. Hisar Lalit were taken as rootstocks for grafting while the tomato cultivars Arka Samrat and Dona-55 were taken as scions. The susceptible and cultivated hybrids, Arka Samrat and Dona-55 were grafted onto resistant rootstocks S. torvum and S. lycopersicum cv. Hisar Lalit. Cleft grafting method was adopted for grafting. The highest success rate of grafting was recorded on Arka Samrat grafted onto S. torvum followed by Dona-55 grafted onto S. torvum. Arka Samrat and Dona-55 grafted onto S. torvum showed maximum reduction in number of galls, egg masses per root system, final nematode population and rate of reproduction with increased number of fruits per plant, fruit weight and total fruit yield per ha followed by Arka Samrat and Dona-55 grafted onto S. lycopersicum cv. Hisar Lalit. Delayed flowering and fruiting were observed in grafted plants as compared to non-grafted plants. This delayed flowering in grafted plants was found to be of advantage as it led to increased yield.
Open Access
Management of phytonematodes in tomato (Solanum lycopersicum L.) by poultry manure
(2023) K, Narmadha; Choudhury, B.N.
Studies were carried out to evaluate the efficacy of poultry manure at different doses against root-knot nematode, Meloidogyne incognita and other phytonematodes in tomato under field condition. Effect of poultry manure on soil available nutrients and soil microbes were also recorded. Poultry manure was applied in the field at 7 days before transplanting of seedlings. The treatment Poultry manure @1500 kg/ha was found to be best in reducing the phytonemtodes population in soil including Meloidogyne incognita, which results in improved plant growth and yield of tomato over control. Nimitz (Fluensulfone 2G) being an nematicide remained at par with the treatment Poultry manure @1500 kg/ha in reducing plant parasitic nematodes in soil. Effect of different doses of poultry manure on soil available nutrients showed that the treatment Poultry manure @1500 kg/ha was found to be best in increasing the available nutrients like Nitrogen, Phosphorus and Potassium in soil which was followed by Poultry manure @1000 kg/ha over control. Studies on effect of different doses of poultry manure on soil microbes revealed that application of Poultry manure @1500 kg/ha increased the population of total fungi and bacteria in soil which was 5.36% and 5.32% over control respectively. Poultry manure at increased rates was inversely proportional to the phytonematodes population in soil and directly proportional to plant growth, yield, available nutrients and microbes in soil.
Open Access
PATHOGENICITY AND MANAGEMENT OF RENIFORM NEMATODE (Rotylenchulus reniformis LINFORD & OLIVEIRA, 1940) ON TOMATO (Solanum lycopersicum)
(2023) Bhuyan, Prerana; Devi, Gitanjali
A survey of plant-parasitic nematode, Rotylenchulus reniformis Linford & Oliveira, 1940 was carried out at the Experimental field of Department of Horticulture, AAU, Jorhat during Rabi and Kharif season, 2022-2023. Analysis of 200 soil and root samples collected from the root rhizosphere of different vegetable, fruit and ornamental crops showed the presence of Rotylenchulus reniformis with 54.2% Frequency of occurrence with 123 mean population density/ 250 cc of soil in vegetable crops, 40.0% Frequency of occurrence with 86 mean population density 250 cc of soil in fruit crops, and 35.0% Frequency of occurrence with 59 mean population density 250 cc of soil in ornamental crops. Pathogenicity of reniform nematode, R.reniformis, was investigated on tomato var. Pusa Ruby by inoculating 10, 100, 500, 1000, 5000 and 10000 nematodes per kg autoclaved soil in root zone of 10 days-old plants. Observations on growth parameters of plants and nematode numbers were recorded at 60 days following inoculation. There was a progressive decrease in the plant growth parameters as the inoculum level of R. reniformis increased. Significant reduction in growth parameters were recorded at 1000 and above nematodes/kg soil. There was a gradual increase in the number of females, egg masses per root system, and nematode population of R. reniformis as the inoculum level increased. The rate of multiplication decreased with increase in the level of inoculation. The threshold level of R. reniformis was found to be 1000 nematodes per kg soil. Investigations were carried out to evaluate the efficacy of two chemical viz., Fluensulfone and Fluopyrum for the management of R. reniformis on tomato (var. Pusa Ruby) under net house condition. All the treatments with chemicals differed significantly from the untreated control. The maximum plant growth parameters in tomato var. Pusa Ruby were recorded in the treatment with Nimitz® (Fluensulfone) @2.5kg/ha followed by, treatment with Carbofuran CG @3.0 kg a.i./ha, treatment with Velum Prime (Fluopyrum) @1000 ml/ha, and treatment with Nimitz® (Fluensulfone) @2.00 kg/ha , treatment with Velum Prime (Fluopyrum) @750 ml/ha. The chemicals suppressed nematode reproduction as indicated by the lower nematode population and lower numbers of eggs found on the roots of tomato as compared to control. The minimum populations of R. reniformis were recorded with the treatment Nimitz® (Fluensulfone) @2.5kg/ha followed by treatment with Carbofuran CG @3.0 kg a.i./ha, treatment with Velum Prime (Fluopyrum) @1000 ml/ha, treatment with Nimitz® (Fluensulfone) @2.00 kg/ha , treatment with Velum Prime (Fluopyrum) @750 ml/ha.
Open Access
BIO-MANAGEMENT OF ROOT-KNOT NEMATODE, MELOIDOGYNE INCOGNITA IN OKRA
(2023) Lourembam, Manjeet; Borah, Aparajita
In the present study on screening of okra varieties against root-knot nematode, Meloidogyne incognita, all the nine varieties of okra viz., Kashi Lalima, NOH-7100, Laksmi-500, OH-940, Basanti, S-51, Arka Abhay, BHS-280 and Pusa sawni were found to be susceptible to M.incognita. In the study on the efficacy of essential oil for the management of root-knot nematode, M.incognita in okra under net house condition showed that all the treatment were effective in increasing plant growth parameters shoot length, fresh weight and dry weight of shoot and root in okra. All the treatments significantly decreased numbers of galls, egg masses and final nematode population in soil. The treatment with Nimitz@1.5g/pot showed maximum increase in plant growth parameters with reduction of galls,egg masses and nematode population in soil.Among the different treatments with essential oils, seed treatment with Neem oil@20%v/w was found to be most effective in increasing plant growth parameters with reduction in numbers of galls, egg masses and nematode population in soil.
Open Access
Management of Meloidogyne incognita in black gram using of botanicals
(2023) Timungpi, Lirbon; Mahanta, Bornali
Studies on the efficacy of chopped leaves for the management of Meloidogyne incognita in black gram under net house condition showed that all the treatments were effective in increasing plant growth parameters shoot length, fresh weight and dry weight of shoot, fresh weight and dry weight of root in black gram. All the treatments significantly decreased number of galls, egg masses and final nematode population in soil. The treatment with water hyacinth 1.5% (w/w) was found to be effective in increasing plant growth parameters in black gram and reducing the number of galls, egg masses and final nematode population in soil. All the nine varieties viz., SBC-50, SBC-51, SBC-47, Manab, Beki, Kolong, Sonkush, SBC-40, and IPU-31 of black gram were found to be susceptibile to Meloidogyne incognita.
Open Access
MICROBIAL CHARACTERIZATION OF ROOT KNOT NEMATODE (Meloidogyne incognita) INFECTED RHIZOSPHERE
(2023) Doley, Jitendra; Borgohain, Nibedita
Present study was carried out to characterize the microbes associated with rootknot nematode infected rhizosphere and also to evaluate their biocontrol potential against two important nematode pests i.e., Meloidogyne incognita and M.graminicola in laboratory condition. A total of 40 numbers of bacteria/fungal/actinobacteria were isolated from nematode infested rhizospheric soil collected from Golghat, Nagaon and Majuli districts of Assam. The isolates ANKBF1 and AMRCF2 were identified as Penicilium cetrinum and Aspergillus terreus respectively and isolate AGKOB1 was identified as Bacillus pumilus on the basis of molecular characterization. To evaluate their biocontrol potential, culture filtrates of all the isolated bioagents were tested for egg hatching inhibition and second stage juvenile mortality of root-knot nematode and rice root-knot nematode under laboratory condition. Studies revealed that all the isolates of bacterial, fungal and actinobacterial exhibited maximum egg hatching and juvenile mortality of root-knot nematode (M. incognita and M. graminicola) in 25, 50 and 75 percent concentration of filtrates at 12, 24, 48 and 72 hours of exposure under in-vitro condition. However, the efficacy was varied among the isolates. Among the identified isolates the maximum egg hatch inhibition (54%-61.17%) and the nematode (M. incognita and M. graminicola) juvenile mortality (92.67%-96.33) with low LC50value (20.71%-13.01%) was observed in 75% concentration of fungal isolate ANKBF1 viz, Penicilium cetrinum as well as bacterial isolates AMRCF2 viz, Bacillus pumilus at 72 hrs of exposures. This was followed by isolate AMRCF2 ( Aspergillus terreus) prevent egg hatching range from (49.17%-50.50%) at high concentration @ 75 percent and caused 73.67%-82% J2 mortality of root knot nematodes after 72 hrs with LC50 value 25.12%-31.78%.
Open Access
BIO-INTENSIVE MANAGEMENT OF Meloidogyne incognita IN GREEN GRAM, Vigna radiata
(2023) Maio, Jarine; Borah, Aparajita
A laboratory experiment was carried out for in-vitro efficacy of six different plant extracts viz., Azadirachta indica, Lantana camara, Polygonum hydropiper, Eclipta prostrata, Ricinus communis and Tinospora cordifolia on the mortality of second stage juveniles (J2) of Meloidogyne incognita. Various concentrations of aqueous leaf extracts of 25%, 50% and 100% were assessed with exposure time period for 24, 48 and 72 hrs. All the extracts showed significant effect on the mortality of M. incognita over control (distilled water). Among the plant extracts L. camara and A. indica showed maximum percent mortality at 100% concentration after 72 hrs of exposure time. The minimum mortality of M. incognita was observed in T. cordifolia at all concentrations. No mortality was recorded in control (distilled water). Studies on the effect of different plant extracts, Neem seed kernel powder, Trichoderma harzianum and Nimitz on green gram for the management of M. incognita under net house condition showed that all the treatments increased in plant growth parameters and reduced number of galls, eggmasses per root system and nematode population in pot compared to the untreated control. Among the seed treatments, T. harzianum @ 5ml/g of seed showed maximum increase in plant growth parameters with reduced number of galls, eggmasses per root system and nematode population in soil.
Open Access
STUDY ON COMPARATIVE FIELD EFFICACY OF AAU DEVELOPED MICROBIAL FORMULATIONS AGAINST Meloidogyne incognita CAUSING ROOT-KNOT DISEASE OF OKRA.
(2023) Hazarika, Angshuman; Das, Debanand
Pot experiment was carried out during Kharif 2022 in the Net House of Department of Nematology, AAU, Jorhat-13 to evaluate the efficacy of five AAU developed bioformulations viz.,Bio-Veer, Bio-Monas, Biofor-Pf2, Biogreen and AAU Bioguard against Meloidogyne incognita in okra under Net house condition. 2000 cc capacity pots were filled with sterilized pot mixture of soil: sand : clay @ 2:1:1. Bioformulations were applied in the pots as per the treatments viz., T1 : Bio-Veer @20g/kg soil; T 2 : Bio-Monas @ 20g/kg soil; T 3 : Biofor- Pf2 @ 20g/kg soil; T4 : Biogreen @ 20g/kg soil; T5: AAU Bioguard @ 20g/kg soil one week prior to sowing the seeds. One untreated control was kept for comparison. Three to four leaved okra seedlings were inoculated with freshly hatched second stage juvenile of M. incognita 1J2/g of soil. The experiment was terminated at 60 days after sowing. It was revealed that all the AAU developed bio-formulations significantly increased the growth of okra and reduced the nematode infestation. However, Biogreen exhibited the best result in increasing the plant growth parameters and reducing the nematode infestation, followed by and Biofor-Pf2. Two promising AAU developed bio-formulations (Biogreen and Biofor-Pf2) were tested under field condition in a naturally infested field of M. incognita in okra during Kharif 2023. The treatments were: T1 : Application of Biogreen @ 1.5 tons/ha; T2 : Application of Biogreen @2 tons /ha; T3 : Application of Biofor Pf2 @ 1.5 tons/ha; T4 : Application of Biofor Pf2 @ 2 tons/ha; T5 : Application of decomposed cowdung @ 2 tons/ha; T6 : Chemical control (Fluensulfone 2% Gr @ 1 kg ai/ha) T7 : Control. The experiment was conducted in 3mx4m size plots following RBD. The result revealed that both the bio-formulation was effective in increasing plant growth parameters of okra and reducing the infestation of M. incognita. Amongst the bio-formulations, application of Biogreen @ 2t/ha gave the best result in increasing plant growth parameters of okra and reducing the infestation of M. incognita followed by application of Biogreen @ 1.5 t/ha.

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