Reduced Nematode Populations Research Articles

Eco-friendly biocontrol of pine wilt disease: Enhancing tree defense with Bacillus subtilis JCK-1398 for sustainable forest management

Pine wilt disease (PWD), caused by pinewood nematodes (Bursaphelenchus xylophilus), poses a significant threat to forestry worldwide. This study introduces a novel biocontrol strategy using Bacillus subtilis JCK-1398, which was selected and identified for its resistance-induction potential after extensive screening of microbial strains from pine tissues. The bacterium was found to biostimulate resistance in Pinus densiflora. Comprehensive analyses, including transcriptomics, qPCR assays, and high-performance liquid chromatography (HPLC), revealed that B. subtilis JCK-1398 significantly upregulates defense-related genes and stimulates pinoresinol production, a compound linked to resistance against nematodes. Treatment with B. subtilis JCK-1398 suppressed nematode migration and reduced nematode populations within pine tissues, effects attributed to the enhanced tree defense response. Field trials corroborated these findings, demonstrating a 72 % decrease in PWD incidence with aerial application of JCK-1398, confirming its potential for large-scale forest application. This biocontrol strategy, leveraging the stimulation of plant defense by B. subtilis JCK-1398, presents a promising and scalable, eco-friendly solution for managing PWD. Overall, this study provides new insights into the interactions between the bioagent, the host tree, and the pest nematode, offering an effective and sustainable approach to mitigate pine wilt disease.

Effectual Role of Plant Growth-Promoting Fungi and Fosthiazate in Controlling Tomato Root-Knot Nematode Infection: In Vivo and In Vitro Studies

Plant growth-promoting fungi (PGPF) are known to induce systemic resistance in plant diseases caused by microbial pathogens. However, the induced resistance by PGPF has not yet been elucidated in plant diseases caused by root-knot nematodes (RKNs, Meloidogyne spp.). Meloidogyne incognita can severely damage tomato plants, causing considerable losses in world yields. This study aimed to isolate and evaluate the potential of PGPF through enhancing systemic resistance, possibly through activating defense-related pathways in tomato plants, comparing to the commercial chemical nematicide, Melithorin® (fosthiazate 90%). The most potent PGPF (K7, K13, K14) were identified morphologically and molecularly as Alternaria photistica, Penicillium buchwaldii, and Aspergillus niger, respectively. We tested the efficacy of these fungi against RKN (M. incognita) both in vitro and in vivo. The results demonstrated that the commercial nematicide fosthiazate (90%) was the most effective treatment for controlling RKN J2 larvae, achieving a mortality rate of 94% after 96 hours. This was followed by the PGPF treatments, with A. niger at 92.6%, P. buchwaldii at 87.7%, Verticillium lecanii at 73.3%, and A. photistica at 47.4%. Additionally, applying A. photistica, A. niger, P. buchwaldii, and V. lecanii significantly enhanced the levels of photosynthetic pigments, total carbohydrates, and proteins in both healthy and RKN-infected plants. Notably, Melithorin® (fosthiazate 90%), A. niger, and V. lecanii led to substantial increases in root carbohydrate content, with increases of 97%, 63%, and 58%, respectively. Furthermore, Melithorin®, A. photistica, and A. niger significantly boosted shoot protein content by 68%, 65%, and 49%, respectively, compared to the infected control group. These findings indicate that both nematicide and fungal treatments effectively reduce nematode populations and improve overall plant health and nutrient composition. At the same time, the results appeared that infected plants treated with PGPF or Melithorin® showed variation in number and molecular weight of protein bands. SDS-PAGE results indicated that, the highest number of bands (twelve) was recorded in the infected plants treated with Melithorin® followed by P. buchwaldii (11 bands), A. photistica (10 bands), V. lecanii (8 bands), and A. niger (7 bands), respectively. Also, the application of Melithorin®, A. niger, and V. lecanii resulted in a significant increase in the number and weight of fruits, respectively, compared to healthy control plants. Our results suggested that A. photistica, A. niger, P. buchwaldii, and V. lecanii could be used as effective and safe nematicides against RKNs.

The Distribution of Reniform Nematode (Rotylenchulus reniformis) in Cotton Fields in Central Queensland and Population Dynamics in Response to Cropping Regime.

Reniform nematode (Rotylenchulus reniformis) causes significant yield loss in cotton worldwide. In 2012, its detection in the Dawson-Callide region of Central Queensland prompted extensive surveys of cotton fields. The nematode was confirmed in 68% of sampled fields, with populations ranging from 2 to 3870 R. reniformis/200 mL of soil. Soil monitoring revealed increasing populations associated with consecutive cotton crops. However, when corn or sorghum replaced cotton, soil nematode populations significantly decreased. A two-year replicated field trial demonstrated that growing a non-host crop (such as biofumigant sorghum 'Fumig8tor', grain sorghum, or corn) significantly reduced nematode populations in the top 15 cm of soil compared to cotton. Unfortunately, when cotton was replanted the following season, nematode populations rebounded regardless of the previous crop. Only the 'Fumig8tor'-cotton rotation resulted in significantly lower nematode populations than continuous cotton. Vertical soil sampling showed that rotating with a non-host crop significantly reduced nematode densities to a depth of 100 cm compared to cotton. However, when the field was replanted with cotton, nematode populations recovered, unaffected by cropping or soil depth. This study emphasises the importance of monitoring reniform nematodes in cotton soils for early detection and defining distribution patterns within a field, which may improve the effectiveness of management practices. These results suggest that one rotation out of cotton is not sufficient, as populations return to high levels when cotton is grown again. Therefore, two or more rotations out of cotton should be considered to manage this nematode.

Characterization of finger millet extracts and evaluation of their nematicidal efficacy and plant growth promotion potential.

Plant-parasitic nematodes pose a significant threat to finger millet crops, potentially causing yield reduction of up to 70%. Extracts derived from finger millet varieties contain potent bioactive compounds that can mitigate nematode damage and promote plant growth. This study aimed at isolating and characterizing bioactive compounds from the finger millet varieties Ikhulule, Okhale-1, and U-15; evaluating the impact of Ikhulule and U-15 extracts on the mortality of the root lesion nematode Pratylenchus vandenbergae; assessing the growth promotion effects of Ikhulule and U-15 extracts on the finger millet variety Okhale-1; and determining the efficacy of these extracts in managing plant-parasitic nematodes under greenhouse conditions. Extracts were obtained from both leaves and roots and tested invitro for nematode mortality and invivo for growth promotion and nematode control. The results showed that finger millet extracts exhibited strong nematicidal properties invitro, achieving a mortality rate of up to 98% against P. vandenbergae nematodes. Applying these extracts to finger millet shoots significantly reduced nematode populations in both soil and roots and decreased the reproductive factor to below one (1), indicating an effective nematode control. The study attributes the enhanced nematicidal effects of finger millet extracts to their bioactive compounds, particularly dodecanoic acid, phytol, 1,1,4a-trimethyl-6-decahydro naphthalene, 2,3-dihydro-benzofuran, 2-methoxy-4-vinylphenol and ethyl ester, and hexadecanoic acid. These findings suggest that finger millet-derived extracts offer a natural solution for nematode management and broader agronomic benefits, ultimately contributing to overall plant health and productivity.

Isolation and Characterization of a (Surfactin-Like Molecule) Produced by Bacillus subtilis: Antagonistic Impact on Root-Knot Nematodes

Plant-parasitic nematodes are severe soil-borne pathogens that cause significant damage to agricultural products each year, resulting in substantial financial losses globally. Thus, there is an urgent need to identify novel biological control agents or nematicides. The nematicidal potential of Bacillus subtilis-derived lipopeptides against Meloidogyne incognita was investigated at various concentrations (35 ppm, 25 ppm, 15 ppm, 5 ppm) under in vitro conditions. Egg hatching inhibition and mortality of second-stage juveniles (J2s) of M. incognita were analyzed after exposure for 6, 12, 24, 48, and 96 hours. Data showed that with the increase in concentration and exposure period, egg hatching inhibition and percent mortality increases. Maximum percent mortality of J2s was reported at 35ppm i.e., 45%, 55%, 67.75%, 77% and 85% at 6, 12, 24, 48 and 96 hrs, respectively. The maximum ovicidal activity was reported at 35ppm concentration, with 84.61% of eggs hatching inhibition on 96 hrs of the exposure period. The bacterial culture suspension of Bacillus subtilis and Pseudomonas putida at1.2x108cfu/ml, and the crude lipopeptide (35ppm) was also investigated as a biological control agent against M. incognita on tomato in a pot experiment under glasshouse condition. Combinational treatment of P. putida and B. subtilis culture, prior to inoculation of M. incognita on tomato plant caused a significant increase in plant growth attributes and in biochemical parameters over the inoculated control. In the same treatment, the maximum reduction in nematode population and root galling was recorded. However, in the crude lipopeptide experiment study, root dip and inoculation of crude lipopeptide in tomato after the introduction of M. incognita caused a major augment in all the parameters over the inoculated control. MALDI-TOF MS analysis of crude lipopeptide shows surfactin like molecules at m/z 1058 [M+Na]+. It is concluded that crude lipopeptide or combinational treatment of B. subtilis and P. putida culture suspension can be employed as a biocontrol agent against M. incognita and may act as a source of a novel nematicidal agent of bacterial origin.

Understanding the dynamics of Meloidogyne incognita infestation in pomegranate orchards of Himachal Pradesh, India (year 2018, 2019 and 2021) and its management strategies

This study investigates the prevalence and dynamics of pomegranate wilt disease induced by Meloidogyne incognita across the Kullu, Mandi and Solan districts of Himachal Pradesh (India), revealed notable spatial and temporal variations in nematode populations and galling severity across the regions. The highest average nematode infestation of 9.25 % was observed at Nauni with highest counts of average second-stage juvenile (J2) larvae (449 larvae per 100 cc of soil) followed by Hurla (Kullu) with 7.42 % infestation. Correlation analysis reveals a strong positive relationship between larval population and galling severity suggesting a potential link between nematode levels and plant damage. Common disease symptoms were leaf size reduction, yellowing and gradual decline of pomegranate plants, often observed in patches within orchards. Microscopic identification revealed distinctive pear-shaped body of mature females while J2 larvae displayed vermiform shapes and the associated species of M. incognita was confirmed through examination of the perineal pattern. Pathogenicity test reveals initiation of leaf yellowing symptom after 45 days of inoculation of larval suspension and root galling was observed after 60 days onward followed by plant decline under greenhouse conditions. Results from pot and field experiments demonstrated the efficacy of Fluopyram and Fluensulfone in reducing nematode populations and galling severity. Treatment with drenching of Fluopyram at the rate of 2 ml/L reduced 98.56 % larvae under field and 99.00 % larvae/100 cc soil under pot conditions. Statistical analysis (paired t-test and MANOVA) confirms significant differences in galling severity and larval population before and after drenching. The study also underscores the importance of weed management in disease mitigation as several weed species (Chenopodium album and Solanum nigrum) were identified as potential reservoirs for M. incognita in infested pomegranate plant basin. This investigation contributes to the advancement of management practices for pomegranate cultivation that addresses both nematode and weed infestations ultimately enhancing crop resilience and productivity.

Bacillus, Pseudomonas and Serratia control Meloidogyne incognita (Rhabditida: Meloidogynidae) and promote the growth of tomato plants

Plant-parasitic nematodes cause significant losses in agriculture worldwide. Among these parasites, the root-knot nematode (Meloidogyne spp.) stands out. Consequently, control methods are being developed to combat this pest. Among these methods is biological control, the main agents of which are bacteria. This study aimed to evaluate the impact of 102 bacterial isolates on the mortality of Meloidogyne incognita J2 juveniles, hypothesizing that certain isolates could effectively control the nematode and promote tomato plant growth. Five experiments were conducted to test this hypothesis. First, the effect of the 102 bacterial isolates on J2 mortality was assessed under laboratory conditions. Second, five isolates (Bacillus cereus IBCBb130, Bacillus cereus IBCBb116, Pseudomonas aeruginosa IBCBb122, Bacillus proteolyticus IBCBb136, and Serratia sp. IBCBb118), which showed >68% J2 mortality, were evaluated over 72 h. Third, these isolates were tested at seven different concentrations. Fourth, their efficacy in controlling M. incognita on tomato plants was assessed in a greenhouse setting. Fifth, their potential to promote tomato plant growth without nematode inoculation was evaluated. The results revealed that the 102 bacterial isolates caused mortality ranging from 2 to 79.57% for M. incognita J2. At a 10% dilution, five isolates (B. cereus IBCBb130, P. aeruginosa IBCBb122, B. cereus IBCBb116, B. proteolyticus IBCBb136, and Serratia sp. IBCBb118) maintained mortality rates above 68%. Among these strains, B. cereus IBCBb130 and P. aeruginosa IBCBb122 were particularly effective, with B. cereus IBCBb130 showing high mortality rates under laboratory conditions and P. aeruginosa IBCBb122 significantly reducing nematode populations in greenhouse pots. Additionally, Serratia sp. IBCBb118 demonstrated notable potential for promoting tomato plant growth. In conclusion, specific bacterial isolates exhibit strong potential for the biocontrol of M. incognita and enhancement of tomato plant growth, suggesting a viable alternative to chemical nematicides. These findings provide insight into the development of sustainable agricultural practices through targeted manipulation of the soil microbiota. Future research should explore the underlying mechanisms of these interactions and their long-term effects on crop yield and soil health.

Lure and starve: Host root exudates to suppress field populations of cyst nematodes

Plant parasitic nematodes are a burden to global food security, accounting for substantial yield losses in agricultural production worldwide. Increasing concerns over the environment and health issues have led to diminishing control options at the disposal of agricultural producers. Lure and starve, a strategy that is based on stimulating hatching of second stage juveniles (J2) of some cyst forming plant parasitic nematodes in the absence of their host plant seems a promising approach to maintain sustainability in crop production. Here we examined in-situ hatching of encysted eggs of the potato cyst nematode Globodera pallida and the carrot cyst nematode Heterodera carotae following exogenous applications of host root exudates in repeated field experiments during autumn and spring seasons. Population densities (viable J2 g−1 of soil) were assessed prior and post-application of root exudates. Results showed hatching induction of up to 83 % for G. pallida and 54 % for H. carotae in field plots drenched with their respective host root exudates. Spring season experiments were characterised by limited soil moisture and did not reduce nematode population densities for G. pallida. The potential for host root exudates in suppressing field population of cyst nematode in lure and starve strategies looks promising for both cyst nematode species investigated.

Cotton host resistance as a tool for managing Rotylenchulus reniformis in Louisiana.

The reniform nematode, Rotylenchulus reniformis, is a major yield-limiting pest of upland cotton (Gossypium hirsutum) in the United States that has been steadily increasing in incidence in many states. Reniform nematode-resistant cotton cultivars have recently become commercially available for cotton producers; however, few field trials have evaluated their efficacy as a nematode management tool. The aim of this study was to evaluate reniform nematode population development, plant growth, and seed cotton yield of reniform nematode-resistant cotton cultivars in two nematode-infested fields in Louisiana. Replicated small-plot field trials were conducted in St. Joseph, LA (NERS field) and Winnsboro, LA (MRRS field) during the 2022 and 2023 growing seasons. In 2022, cultivars evaluated included: (1) DP 1646 B2XF (susceptible/tolerant), (2) DP 2141NR B3XF (resistant), (3) PHY 332 W3FE (resistant), (4) PHY 411 W3FE (resistant), and (5) PHY 443 W3FE (resistant). In 2023, an additional susceptible cotton cultivar, PHY 340 W3FE, was also included. All nematode-resistant cotton cultivars evaluated provided suppression of reniform nematode population development relative to that of the susceptible cotton cultivars, with suppression of nematode soil population densities at harvest ranging from 49 - 81% relative to DP 1646 B2XF. The resistant cultivar PHY 411 W3FE provided the most consistent suppression of reniform nematode population development, reducing reniform nematode soil population densities at harvest in both field locations and both trial years. In contrast, DP 2141NR B3XF only reduced soil population densities at harvest in the NERS field in 2023. Despite relatively consistent nematode suppression and improvements in plant vigor ratings and canopy coverage associated with the resistant cotton cultivars, a yield increase was only observed with PHY 332 W3FE and PHY 411 W3FE planted at the NERS field in 2023. Despite strong resistance to reniform nematode in the evaluated cotton cultivars, nematode soil population densities still increased during the growing season in plots planted with resistant cotton cultivars, emphasizing the need for additional management tactics to use alongside host resistance. This study indicates that new reniform nematode-resistant cotton cultivars show promising potential to reduce nematode population development during the growing season in Louisiana.

Efficacy of Purpureocillium lilacinum AUMC 10149 as biocontrol agent against root-knot nematode Meloidogyne incognita infecting tomato plant.

Root-knot nematode Meloidogyne incognita is among the biotic factors which has greatly affected both the yield and the quality of the tomato crop. The egg parasitic nematode, Purpureocillium lilacinum (Pl) is considered as one of the most promising agents in controlling and overcoming this plant pathogen. The nematicidal effect of the native isolate Pl AUMC 10149 on second stage juvenile's survival and egg hatching of M. incognita at different times of exposure was tested in vitro. The obtained data showed that Pl gave a maximum percentage of J2 mortality (97.6%) and egg hatching inhibition (79.8%) after 72 hours of exposure. The potentiality of Pl as well as Bio-Nematon to control M. incognita infecting tomato was conducted using different times of application in vivo. Nine treatments with five replicates were used for such bioagents compared with the nematicide Oxamyl. Each seedling was inoculated with 1000 J2s of nematode/pot and 10 mL of Pl (1x1010 CFU/mL) or Bio-Nematon spore suspension (1x108 CFU/mL) 10mL/pot. The results indicated that the most effective treatments in reducing nematode population, number of galls and egg masses of M. incognita in plant roots was performed with treatment by Pl pre-planting and post-infection with Pl (Rf 1.9) giving a significant enhancement in plant length (64.9%), fresh weight (72.52%) and shoot dry weight (163.41%) without negatively impacting environment. Therefore, the present study confirmed that using P. lilacinum AUMC 10149 can be used as a practical supplement to environmentally friendly disease management of root-knot nematodes in Egypt.

Metarhizium carneum Formulations: A Promising New Biological Control to Be Incorporated in the Integrated Management of Meloidogyne enterolobii on Tomato Plants.

The increase in the populations of root-knot nematode Meloidogyne enterolobii in various vegetables such as tomatoes grown under greenhouse conditions as well as increasing restrictions on the use of certain chemical nematicides have led to the search for new, effective management strategies, preferably ones that are sustainable biological alternatives. In this work, two formulations of the nematophagous fungus Metarhizium carneum, one concentrated suspension and one wettable powder, were evaluated under greenhouse conditions to reduce the M. enterolobii infestation in tomato plants. In addition, the effectiveness of the liquid formulation of M. carneum was compared with two biological and three chemical commercial nematicides. The results show that the two M. carneum formulations reduced the M. enterolobii population density by 78 and 66% in relation to the control treatment. In comparison, the liquid formulation of M. carneum and Purpureocillium lilacinum treatments reduced nematode population density by 72 and 43%, respectively, while for metam sodium preplanting applications followed by M. carneum applications during the tomato growth stage, the reduction was 96%. The alternate use of some chemical compounds plus the application of M. carneum as a biocontrol is a good starting strategy for managing M. enterolobii populations. These results confirm that M. carneum is a serious candidate for the short-term commercialization of an environmentally friendly biological nematicide.

Sustainable Management of Root- Knot Nematode (Meloidogyne javanica) on Brinjal

Brinjal (Solanum melongena) is an important Solanaceae family vegetable, which is grown all around the world. It is affected by various fungal, bacterial, viral, nematode diseases but it is a major host for root-knot nematode, Meloidogyne javanica. Hence, for effective management of root-knot nematode experiment was conducted in field condition using the culture filtrate (3gm/kg soil) of bio-agents (viz., Trichoderma viride, Trichoderma harzianum, Purpureocillium lilacinum, Pochonia chlamydosporia and Pseudomonas fluorescens). The findings of the experiments revealed that, when compared to the control, all of the tested bio-agents considerably improved plant development characteristics and decreased nematode populations. Among the tested bio-agents T. viride was found most effective treatment with improve plant growth characters as well as in reducing nematode population over other treatment in field condition.

Population of root knot nematode, Meloidogyne incognita and yield in tomato using various \bio agents under pot culture conditions

Tomato (Solanum lycopersicum) is one of the most important vegetable which has a great economic importance and also has a high processing value. Tomatoes are susceptible to root-knot nematode (Meloidogyne incognita) leading to a great economic loss. The life cycle of root-knot nematode takes about 25 days to complete. Second stage juveniles J2 initiate infection in the host. Root-knot nematodes constitute a major group of plant-parasitic nematodes causing extensive economic damage ton early all crop plants of economic importance in both tropical and sub-tropical crop production regions all over the world (Sikora and Fernandez, 2005). The efficacy of different bioagents like Trichoderma viride, Bacillus subtilis, Pochoniachlamy disporia, Purpureocillium lilacinum against Meloidogyn eincognita was estimated under four replications and assessment of plant morphometric characters and root knot index under pot culture conditions has been recorded. All the four bioagents were tested in vitro to study their efficacy against Meloidogyne incognita. Among all the bioagents tested, Purpureocillium lilacinum treatment showed significant increase in root length and shoot length (40.20cm and 76.20cm, respectively) and the untreated control plants recorded the least roo tlength and shoot length (19.11cm and 21.30cm). All the treatments were found to reduce nematode population in roots and highest reduction was noticed in Purpureocillium lilacinum treated plants (178.50 and 141.20) soil (250g) and root (5g), respectively. The untreated plants recorded the highest nematode population of 1314.14 and 1411.20 in soil (250g) and root (5g), respectively. Significant reduction in root knot index (1.2) were observed in the treatment Purpureocillium lilacinum and Carbofuran which recorded (2.0 ) per cent. The untreated control plant roots showed root knot index of 5.00 percent.

Assessment on population of root knot nematode, Meloidogyne incognita and yield in brinjal using various bio agents under pot culture conditions

Brinjal (Solanum melongena) is one of the most important vegetables which has a great economic importance and also has a high processing value. Brinjals are susceptible to root-knot nematode (Meloidogyne incognita) leading to a great economic loss. The life cycle of root-knot nematode takes about 25 days to complete. Second stage juveniles J2 initiate infection in the host.Root-knot nematodes constitute a major group of plant-parasitic nematodes causing extensive economic damage to nearly all crop plants of economic importance in both tropical and subtropical crop production regions all over the world (Sikora and Fernandez 2005). The efficacy of different bioagents like Trichoderma viride, Bacillus subtilis, Pochoniac, hlamydosporia, Purpureocillium lilacinum against Meloidogyne incognita was estimated under four replications and assessment of plant morpho metric characters and root knot index under pot culture conditions has been recorded. All the four bio agents were tested in vitro to study their efficacy against Meloidogyne incognita. Among all the bioagents tested, Purpureocillium lilacinum treatment showed significant increase in root length and shoot length (35.11cm and 59.11cm, respectively) and the untreated control plants recorded the least root length and shoot length (12.02 cm and 15.12cm). All the treatments were found to reduce nematode population in roots and highest reduction was noticed in Purpureocillium lilacinum treated plants (161.11 and 138.10) soil (250g) and root (5g), respectively. The untreated plants recorded the highest nematode population of 1129.11 and 1259.20 in soil (250g) and root (5g) respectively. Singnificant reductionin root knot index (1.0) were observed in the treatment Purpureocillium lilacinum and Carbofuran which recorded (2.2 ) per cent. The untreated control plant roots showed a root knot index of 5.00 percent.

Assessment on population of root knot nematode, Meloidogyne incognita and yield in brinjal using various bio agents under pot culture conditions

Brinjal (Solanum melongena) is one of the most important vegetables which has a great economic importance and also has a high processing value. Brinjals are susceptible to root-knot nematode (Meloidogyne incognita) leading to a great economic loss. The life cycle of root-knot nematode takes about 25 days to complete. Second stage juveniles J2 initiate infection in the host.Root-knot nematodes constitute a major group of plant-parasitic nematodes causing extensive economic damage to nearly all crop plants of economic importance in both tropical and subtropical crop production regions all over the world (Sikora and Fernandez 2005). The efficacy of different bioagents like Trichoderma viride, Bacillus subtilis, Pochoniac, hlamydosporia, Purpureocillium lilacinum against Meloidogyne incognita was estimated under four replications and assessment of plant morpho metric characters and root knot index under pot culture conditions has been recorded. All the four bio agents were tested in vitro to study their efficacy against Meloidogyne incognita. Among all the bioagents tested, Purpureocillium lilacinum treatment showed significant increase in root length and shoot length (35.11cm and 59.11cm, respectively) and the untreated control plants recorded the least root length and shoot length (12.02 cm and 15.12cm). All the treatments were found to reduce nematode population in roots and highest reduction was noticed in Purpureocillium lilacinum treated plants (161.11 and 138.10) soil (250g) and root (5g), respectively. The untreated plants recorded the highest nematode population of 1129.11 and 1259.20 in soil (250g) and root (5g) respectively. Singnificant reductionin root knot index (1.0) were observed in the treatment Purpureocillium lilacinum and Carbofuran which recorded (2.2 ) per cent. The untreated control plant roots showed a root knot index of 5.00 per cent.

Population of root knot nematode, Meloidogyne incognita and yield in tomato using various \bio agents under pot culture conditions

Tomato (Solanum lycopersicum) is one of the most important vegetable which has a great economic importance and also has a high processing value. Tomatoes are susceptible to root-knot nematode (Meloidogyne incognita) leading to a great economic loss. The life cycle of root-knot nematode takes about 25 days to complete. Second stage juveniles J2 initiate infection in the host. Root-knot nematodes constitute a major group of plant-parasitic nematodes causing extensive economic damage ton early all crop plants of economic importance in both tropical and sub-tropical crop production regions all over the world (Sikora and Fernandez, 2005). The efficacy of different bioagents like Trichoderma viride, Bacillus subtilis, Pochoniachlamy disporia, Purpureocillium lilacinum against Meloidogyn eincognita was estimated under four replications and assessment of plant morphometric characters and root knot index under pot culture conditions has been recorded. All the four bioagents were tested in vitro to study their efficacy against Meloidogyne incognita. Among all the bioagents tested, Purpureocillium lilacinum treatment showed significant increase in root length and shoot length (40.20cm and 76.20cm, respectively) and the untreated control plants recorded the least roo tlength and shoot length (19.11cm and 21.30cm). All the treatments were found to reduce nematode population in roots and highest reduction was noticed in Purpureocillium lilacinum treated plants (178.50 and 141.20) soil (250g) and root (5g), respectively. The untreated plants recorded the highest nematode population of 1314.14 and 1411.20 in soil (250g) and root (5g), respectively. Significant reduction in root knot index (1.2) were observed in the treatment Purpureocillium lilacinum and Carbofuran which recorded (2.0 ) per cent. The untreated control plant roots showed root knot index of 5.00 per cent.

Reaction of Winter Cover Crops to Meloidogyne enterolobii and Glasshouse Bioassay for Evaluating Utility in Managing M. enterolobii in Soybeans.

Meloidogyne enterolobii is an invasive and highly aggressive root-knot nematode pathogen impacting the Southeastern United States. Winter cover cropping may be a cost-effective method for reducing populations of M. enterolobii in between summer cash crops, yet a gap in the knowledge remains about the response of these cover crops to M. enterolobii and their utility in suppressing nematode populations prior to a cash crop. A "two-step" glasshouse bioassay was performed to evaluate eight winter cover crops popular in North Carolina for their direct response to M. enterolobii infection, and to quantify their effect in reducing nematode populations for the following soybean plants. Data on cover crop root galling, soybean root galling, soybean shoot fresh weight, soybean root fresh weight, eggs per gram of soybean root, and a modified reproductive factor were collected. Cereal cover crops did not display root galling, and there was significantly less root galling in those soybean plants following cereal winter cover crops when compared to those following broadleaf winter cover crops. Broadleaf winter cover crops resulted in significantly higher eggs per gram of soybean root and modified reproductive factor in the soybean plants, compared to cereal cover crops and non-inoculated controls. Results from this study suggest that cereal winter cover crops may be poor-hosts to M. enterolobii and may significantly reduce M. enterolobii populations before a soybean crop, compared to broadleaf winter cover crops. This study lays the groundwork for management recommendations and future field trials to assess management of M. enterolobii through winter cover cropping.

Kemampuan Jenis PGPR dalam Menekan Serangan Nematoda Puru Akar (Meloidogyne spp.) pada Tanaman Seledri (Apium graveolens L.)

Celery plant (Apium graveolens L.) is a cultivated plant that has high economic value, usually used as food flavoring, cooking seasoning and can also be used as a dish garnish. Functions for health such as drugs to lower high blood pressure for people with hypertension. One pest that can affect the quality and quantity of celery production is root knot nematode (NPA) caused by Meloidogyne spp. This study aims to determine the ability of PGPR species to suppress root knot nematodes (Meloidogyne spp.) on celery. This study was designed using a one-factor Completely Randomized Design (CRD). The factor tested was the effect of giving PGPR types namely elephant grass root, kalakai root, fern root and bamboo root. There were 5 treatments and 4 replications. The results showed that giving PGPR could reduce the intensity of root knot attacks and reduce nematode populations in the soil around the roots, as well as significantly affect the number of leaves (stalks) of celery at the age of 58 and 72 days after planting (dap) and weight. wet celery at the age of 44, 58 and 72 dap.

Alternative Management Strategies and Impact of the Northern Root-Knot Nematode in Daylily Production

Bare-root production of Hemerocallis spp., daylily, is of major economic importance to Michigan's ornamental industry, but production of clean nursery material is challenging due to plant-parasitic nematodes. The northern root-knot nematode, Meloidogyne hapla, is the most important perennial ornamental pathogen in northern North America; it causes over 20% yield loss in Hemerocallis spp. production and reduces marketability and distribution. A field trial was established in 2018 to 2020 at a Michigan commercial nursery to determine effective and long-term management strategies to reduce nematode population levels. Eleven treatments were tested: a control, four bio-nematicides, two nematicides, a nematicide root dip, and three compost blends. Soil samples were taken three times per year, along with annual root samples and plant height measurements. Results indicated that TerraClean 5.0 (hydrogen peroxide) and Majestene 304 ( Chromobacterium subtsugae) nematicides best controlled M. hapla populations by 49 and 37%, respectively, compared with the control, whereas Indemnify (fluopyram) significantly increased plant biomass and yields by 31%. A greenhouse study was conducted to determine the impact of M. hapla on Hemerocallis spp. production by inoculating daylily with varying nematode inoculation densities. Even at low population levels, plant biomass reductions were observed, and M. hapla was readily able to reproduce on Hemerocallis spp. These experiments highlight the importance of managing M. hapla and provide effective, alternative management methods that can reduce the application of fumigants and prevent yield losses to increase profitability for ornamentals.

Reducing Pratylenchus Population in Coffee Seedling with Mycorrhizal Fungi and Mycorrhiza Helper Bacteria

The attack of Pratylenchus coffeae nematode on coffee seedlings can limit coffee growth. The use of beneficial microbes as biofertilizer and bioprotectant is suggested to reduce the nematode attack on coffee seedlings and improve growth. A greenhouse experiment was conducted to observe the effect of arbuscular mycorrhizal fungi (AMF) Glomus spp. and mycorrhiza helper bacteria (MHB) P. diminuta and B. subtilis on coffee seedling growth and P. coffeae populations in the soil and roots. The experiment was set up in a randomized block design with five treatments and three replications. The coffee seedlings were grown in potting soil and inoculated with Glomus spp. combined with 20 g or 30 g of MHB solid inoculant. Seedlings were grown in the greenhouse for 10 weeks. The experiment verified that AMF inoculation combined with MHB did not affect the plant height, leaf number, or plant dry weight but decreased the P. coffeae population in the soil and roots of the seedlings. Inoculation of 20 g of MHB solid inoculant with AMF was more effective in reducing nematode population in soil and roots than 30 g of MHB. This experiment verified that Glomus spp., as well as P. diminuta and B. subtilis enable the control of P. coffeae in coffee seedlings.