PAECILOMYCES LILACINUS ON EGG HATCHING AND LARVAL POPULATION OF MELOIDOGYNE SP.
Bio-control agent Paecilomyces lilacinus was tested against Meloidogyne sp. causing root knot disease in vegetables. The experiment was conducted in Microbiology & Bio-control Laboratory, Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh during the period from July, 2016 to October, 2017 to study in-vitro the effect of P. lilacinus as a bio-agent against Meloidogyne spp. Experiments were set up with four treatments viz., 1. Hatching of single egg mass in sterilized distilled water, 2. Hatching of 10 egg masses in sterilized distilled water, 3. Hatching of single egg mass in sterilized distilled water along with P.lilacinus and 4. Hatching of 10 egg masses in sterilized distilled water along with P. lilacinus. Hatching of egg masses in sterilized distilled water produced huge number of live and active of nematode. Hatching of eggs from egg masses in all samples from different areas greatly inhibited by the inoculation of Paecilomyces lilacinus. Eggs of Meloidogyne sp. were unable to hatch in the presence of P. lilacinus. Application of P. lilacinus decreased the nematode population over control which were less active, and some of them were dead. Moreover, some hatched larvae were directly attacked by mycelia of P. lilacinus, and larvae became inactive and died. Highest percent inhibition of Meloidogyne sp. population by P. lilacinus over control was 91.66%.
Root knot nematode, Meloidogyne spp. causes severe losse of vegetable crops all over the world. Among more than 80 species of the genus Meloidogyne, four important species viz., M. incognita, M. Javanica, M. arenaria and M. hapla were responsible for at least 90% of damages as root parasites (Castagnone-Sereno 2002). Solanaceous vegetables were highly susceptible to infestation by root-knot nematodes of the species M. incognita and M. javanica (Khan et al. 2006).
Number of good nematicides are available to control the problems of the root-knot nematodes associated with vegetables. But for killing the pests, nematicides exerts adverse effects on human beings, livestock and other living things, which come in contact directly or indirectly (Singh et al. 2018). In this condition, there is a need to apply bio-pesticides that are pest specific, nontoxic to human, less expensive, and safe for the environment (Suman and Dikshit 2010). Researchers all over the world are engaged in standardizing nematode management strategies by following non-chemical and eco-friendly approaches such as use of biological control agents to stabilize crop production (Sumathi et al. 2006). Several attempts have been made to use antagonistic fungi to control root-knot nematodes.
MATERIALS AND METHODSAmong the various bio-control agents, the soil-inhabiting fungus Paecilomyces lilacinus is a unique strain with a wide range of activity against the most important plant parasitic nematodes. Tests on potted plants and field plots have shown the fungus to control a wide range of nematode species including the root-knot nematode, Meloidogyne spp. on a number of crops. Its effectiveness was comparable to several chemical nematicides tested (Jatala 1986). P. lilacinus is one of the most widely tested biological control agents used for management of plant-parasitic nematodes (Vasanthi & Kumaraswamy 1999). Siddiqui (2000) reported that P. lilacinus significantly reduced Meloidogyne spp. infection on vegetables. Several efforts for managing root knot nematode using chemicals are not satisfactory to control; cost of chemicals and residue problems has made the nematode management strategy unattractive for the growers and extension specialists. Thus, the present investigation was designed to evaluate the biological potential of P. lilacinus on egg hatching and larval population of Meloidogyne sp.
The laboratory work was carried out in Microbiology & Bio-control Laboratory, Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh. The experiment was conducted during July, 2016 to October 2017. The experiment was done following Completely Randomized Design (CRD).
- lilacinus was collected from Microbiology & Bio-control Laboratory, Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh. Previously, P. lilacinus was isolated from experimental formulation supplied by Haychem (Bangladesh) Limited on Potato Dextrose Agar (PDA) media. The isolated fungus was examined microscopically on the basis of their morphological traits and cultural characteristics of the fungi such as mycelium growth, colony texture, spores production and other characteristics (Abubakar et al. 2005; Ahmad and Jairajpuri 1993).
Collection and identification of egg masses of Meloidogyne sp.
Galled roots of tomato plants were collected by observing above ground symptoms from Bangladesh Agricultural University Farm and nearby areas. Five samples were selected by taking one sample from each area of collection. These were sample no. 1 (Noyarchor), sample no. 2 (Boyra), sample no. 3 (BAU farm), sample no. 4 (Bhabokhali), and sample no. 5 (Sutiakhali). Selected plants were uprooted by digging with spade and sickle. Caution was taken to get intact root system without leaving any root parts or gall produced by nematodes. Nematode eggs were separated from knotted tomato roots in the laboratory. Only well developed light brown and live egg masses were selected. Nematode identification was performed by using photographic microscope (Carl Zeiss Microscope GmbH, Model Stemi 508) at Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh. Meloidogyne spp. was identified by observing their identifying characters such as vermiform (worm shaped), multi-cellular structure and stylet morphology (Eisenback and Hirschmann 1981).
Study of Interaction between Paecilomyces lilacinus and Meloidogyne spp.
The In-vitro experiment was conducted four different treatments viz. 1. Hatching of eggs from single egg mass in sterilized distilled water, 2. Hatching of eggs from 10 egg masses in sterilized distilled water, 3. Hatching of eggs from single egg mass in sterilized distilled water along with Paecilomyces lilacinus, 4. Hatching of eggs from 10 egg masses in sterilized distilled water along with Paecilomyces lilacinus. For hatching of eggs from single egg mass, small sized petridishes (4.5 cm diameter) were selected. For Hatching of 10 egg masses, petridishes of 9 cm diameter were taken. Egg masses collected from different places were placed in different petridishes and small amount of sterilized water was added to it so that the water kept the egg masses wet. Petridishes were incubated at 25 ºC ± 1 ºC. After 5 days, when the nematodes were hatched from the eggs, they were counted under stereomicroscope with the help of a counter.
RESULTS AND DISCUSSION
Paecilomyces lilacinus formeda dense mycelium which gives rise to conidiophores. These bear phialides from the ends of which spores were formed in long chains. Conidia were in divergent chains, globose to sub-globosein shape, and smooth walled to slightly roughened (Fig. 1). Egg-masses of Meloidogyne spp. were separated from the knotted roots and nematodes was characterized by their vermiform structures under the field of compound microscope (Fig. 2). Efficacy of P. lilacinus on hatching of egg was performed on single egg mass and ten egg masses, separately (Fig. 3). In case of single egg mass, hatching of P. lilacinus in sterilized distilled water, all hatched larvae of nematode were found live and active. Highest number of nematodes (116) was hatched from the single egg mass on sample no. 4 collected from Bhabokhali and second highest nematodes (90) were obtained from sample no. 2 collected from Boyra. Egg mass collected from sample no. 1 (Noyarchor), sample no. 3 (BAU farm) and sample no. 5 (Sutiakhali) yielded 76, 57, 54 larvae of Meloidogyne sp., respectively. Hatching of egg from egg masses of all areas greatly inhibited by the inoculation of Paecilomyces lilacinus. In the Paecilomyces lilacinus inoculated petridishes, lowest number of nematodes (7) was hatched from the egg masses of sample no. 1 (Noyarchor) and second lowest nematodes 8) from egg masses were obtained from sample no. 5 (Sutiakhali). In the presence of Paecilomyces lilacinus, single egg mass collected from sample no. 2 (Boyra), sample no. 3 (BAU farm) and sample no. 4 (Bhabokhali), hatched 9, 11, 10 nematodes, respectively. It can be mentioned that nematodes larvae hatched from egg mass with Paecilomyces lilacinus were less active and some of these were dead.
In case of experiment with 10 egg masses, similar types of results were observed. All hatched larvae from egg masses were found live and active. Highest number of larvae (1248) were hatched from the egg masses collected from sample no. 2 (Boyra) and second highest nematodes (1244) were hatched from egg masses obtained from sample no. 4 (Bhabokhali). Hatching of egg masses of all areas greatly inhibited by the inoculation of Paecilomyces lilacinus. In the Paecilomyces lilacinus inoculated petridishes, lowest number of nematode (242) were hatched from the egg masses collected from sample no. 1 (Noyarchor). Number of larvae from sample no. 2 (Boyra), sample no. 3 (BAU farm) and sample no. 4 (Bhabokhali), sample no. 5 (Sutiakhali) were 278, 255, 261 and 283, respectively in the presence of Paecilomyces lilacinus with sterilized distilled water.
Inhibition of egg hatching of Meloidogyne sp. by P. lilacinus was observed in the laboratory (Table. 1). Highest percent inhibition of Meloidogyne spp. population by P. lilacinus over control was 91.66% in an area of egg masses collection. Application of P. lilacinus decreased the nematode population over control. Few larvae were hatched from egg masses of Meloidogyne sp. in the presence of P. lilacinus and these larvae were less active, and some of them were dead (Fig. 4). This finding is in agreement with Holland (2000) who stated that P. lilacinus reduced the number of viable eggs and juveniles of the second generation during the experimental period. Some juveniles of infected eggs showed various degrees of deformity and abnormal development and a number of juveniles that emerged from eggs were infected and showed mycelia growth over their body (Ganaie and Khan 2010 and Jatala 1986, Esphahani and Anaspour, 2006).
In the experiment, it was found that hatching of eggs of all areas greatly inhibited by the inoculation of P. lilacinus. Eggs of Meloidogyne sp. were unable to hatch in the presence of P. lilacinus (Fig. 4A&B). Some hatched larvae were directly attacked by mycelia of P. lilacinus, and larvae become inactive and finally died (Fig. 4C). The action of P. lilacinus against Meloidogyne sp. was interpreted in multitude investigations. Khan, et al. (2006) recorded the penetration of fungal hypha to the female cuticle of Meloidogyne javanica by transmission electron microscopy. Park et al. (2004) reported that P. lilacinus could produce leucino toxin and other nematicidal compounds. In the laboratory test, P. lilacinus infected the eggs of Meloidogyne spp. and destroys the embryos within 5 days because of simple penetration of the egg cuticle by individual hypha aided by mechanical and enzymatic activities (Jatala 1986). It was mentioned that P. lilacinus caused substantial deformation of eggs in Meloidogyne sp. which never matured or hatched (Jatala 1985). The serine protease produced by P. lilacinus might play a role in penetration of the fungus through the egg shell of the nematode (Bonants et al. 1995).
Although the isolates of P. lilacinus show some potentiality as a bio-control agent, the study must be continued to increase its efficacy. It is also important to know the fate of the bio-control agent after it has been applied to the soil (Esphahani and Anaspour 2006). Estimation of the persistence of P. lilacinus after application to the soil indicated that the levels fall after application and it disappears from the soil after a few months of inoculation. This suggests that P. lilacinus will only cause short-term disturbances to the soil biota and will not have any long-term effect as other bio-control agents do (Kerry & de Leij 1992, Lackey et al. 1994). Therefore, the fungus is a potential bio-control agent attacking the infective units of the root-knot nematodes (eggs and juveniles), checking the initiation of the disease and reducing the inoculum potential for successive crops. This effect of P. lilacinus is its most significant attribute.
- lilacinus is not expected to cause any harm to plant roots. But, when egg masses and juveniles of Meloidogyne spp. were present, it attacked and destroyed them to a great extent and improved plant growth. It is clear that, eggs of Meloidogyne spp. unable to hatch into larvae in the presence of P. lilacinus. The entire contents of the egg are then used as a food resource by the fungus and completely destroy the embryo or larva (Khan et al. 1997). Therefore, it is expected that the presence of P. lilacinus before the nematode attack would offer greater protection to plants.
Table 1. Percent Inhibition of Meloidogyne sp. population by Paecilomyces lilacinus over control collected from different areas of Mymensingh
|Sample No.||% Inhibition of nematode population by Paecilomyces lilacinus over control|
|Single egg mass||Ten egg masses|
Fig. 1. Culturing Paecilomyces lilacinus, A. Pure culture of P. lilacinus and B. Microscopic view of P. lilacinus.
Fig. 2. Collection of Meloidogyne spp., A. Egg masses, B. Microscopic view of larva (J2) hatched from egg mass
- A. Study was conducted on single egg mass and Study was conducted on 10 egg masses
Sample no. 1 (Noyarchor), sample no. 2 (Boyra), sample no. 3 (BAU farm) and sample no. 4 (Bhabokhali), and sample no. 5 (Sutiakhali).Each value represents the mean and standard deviation of 3 replicates.
Fig. 3. Effect of Paecilomyces lilacinus on egg hatching of Meloidogyne sp. in sterilized distilled water containing Paecilomyces lilacinus (blue bar) and in sterilized distilled water (red bar) collected from different areas of Mymensingh district.
Fig. 4. Parasitizing the larva of Meloidogyne sp. by P. lilacinus. A. Larva of nematode was unable to hatch from egg due to the presence of P. lilacinus, B. Un-hatched eggs in a egg mass (red marked arrows) of Meloidogyne sp., C. Larva of hatched Meloidogyne sp. (within red cirle) is surrounded by mycelial mat of P. lilacinus
Aberoumand, A. 2010. Comparison of Proximate and Mineral composition between Asparagus officinalis and Momordica dioica, Iranian and Indian Vegetables. Iranica Journal of Energy and Environment (IJEE) 1(3): 196-199.
Agbenin, N. O. 2011. Biological control of plant parasitic nematodes: prospects and challenges for the poor Africa farmer. Plant Protection Science 47(2): 62-67.Abubakar, U. Adamu, T. and Manga, S. 2005. Control of Meloidogyne incognita (kofoid and white) chitwood (root-knot nematode) of Lycopersicon esculentus (tomato) using cow dung and urine. African Journal of Biotechnology 3(8): 379-381.
Ahmad, W. and Jairajpuri, M. 1993. Description of Promiconchus siddiqii sp. n. from Dominica (Nematoda: Mononchida). Afro-Asian Journal of Nematology 3(1): 96-98.
Khan. M. M. A Holland, R. J. and Williams, K. L. 1997. Recent studies on Paecilomyces lilacinus as a bionematicice, suppression of Heterodera avenue populations, infection of Meloidogyne sp. eggs, females and juveniles in a pot trial and Radopholus similes eggs in laboratory studies. Australian Nematology Newsletter 8(2): 17.
Bonants, P. J. Fitters, P. F. Thijs, H. den Belder, E. Waalwijk, C. and Henfling, J. W. D. 1995. A basic serine protease from Paecilomyces lilacinus with biological activity against Meloidogyne hapla eggs. Microbiology 141(4): 775-784.
Castagnone-Sereno, P. 2002. Genetic variability of nematodes: a threat to the durability of plant resistance genes. Euphytica 124(2): 193-199.
Eisenback, J. D. and Hirschmann, H. 1981. Identification of Meloidogyne species on the basis of head shape and stylet morphology of the male. Journal of Nematology 13: 513-521.
Esphahani, M. N. and Anaspour, B. 2006. The effects of Paecilomyces lilacinus on the pathogenesis of Meloidogyne javanica and tomato plant growth parameters. Iran Agricultural Research 24(2): 67-76.
Ganaie, M. A. and Khan, T. B. 2010. Biological potential of Paecilomyces lilacinus on pathogenesis of Meloidogyne javanica infecting tomato plants. Euro. J. Appl. Sci. 2(2): 80-84.
Holland, R. J. 2000. Paecilomyces lilacinus as a biocontrol agent. PhD Thesis, Macquarie University, Sydney. 158 pp.
Jatala, P. 1985. Biological control of Nematodes, In an Advached Treatise on Meloidogyne spp. Sasser JN and Carter CC (eds), North carolina State University Graphicd Raleigh, NC. USA. pp. 303-308.
Jatala, P. 1986. Biological control of plant parasitic Nematodes. Annual Review of Phytopathology 24: 453-489.
Kerry, B. R. and de Leij, F. A. A. M. 1992. Key factors in the development of fungal agents for the control of cyst and root-knot nematodes. Pp. 139-144 in E. C. Tjamos, G. C. Papavizas, and R. J. Cook, eds. Biological control of plant diseases. New York: Plenum Press.
Khan, A. Williams, K. L. and Nevalainen, H. K. M. 2006. Infection of plant parasitic nematodes by Paecilomyces lilacinus and Monacrosporium lysipagum. Biological Control 51: 659-678.
Lackey, B. Jaffee, B. and Muldoon, A. 1994. Effect of nematode inoculum on suppression of root-knot and cyst nematodes by the nematophagous fungus Hirsutella rhossiliensis. Phytopathology 84(4): 415-419.
Nico, A. I. Jimenez-Diaz, R. M. and Castillo, P. 2004. Control of root-knot nematodes by composted agro-industrial wastes in potting mixtures. Crop Prot. 23: 581–587.
Park, J. O. Hargreaves, J. R. McConville, E. J. Stirling, G. R. Ghisalberti, E. L. and Sivasithamparam, K. 2004. Production of leucinostatins and nematicidal activity of Australian isolates of Paecilomyces lilacinus (Thom) Samson, Letters in Applied Microbiology 38: 271–276
Rahim, M. Anowar, M. M. Begum, K. S. and Monjil, M. S. 2016. Management of insect pest and diseases of vegetable crops in Bangladesh (Bengali) . Published by-USAID/ Agro-inputs project (AIP) and agro-input retailers networks (AIRN).
Siddiqui, M. R. 2000. Tylenchida Parasites of Plants and Insects. Second edition, CAB International,Wallingford, UK, 833 p.
Singh, N. S. Sharma, R. Parween, T. and Patanjali, P. K. 2018. Modern Age Environmental Problems and their Remediation. Springer International Publishing. doi.org/10.1007/978-3-319-64501-8_3.
Suman, G. and Dikshit, A. K. 2010. Biopesticides, an ecofriendly approach for pest control. Journal of Biopesticides 3(1): 186–188.
Sumathi, M. Parthiban, S. and Samuel, S. D. 2006. Effect of graded doses of nitrogen and VAM on herbage, oil yield and nematode population on patchouli (Pogostemon patchouli Pellet). Indian Journal of Nematology 36(2): 190-194.
Vasanthi, D. and Kumaraswamy, K. 1999. Efficacy of vermicompost to improve soil fertility and rice yield. Journal of the Indian society of soil science, 47(2): 268-272.
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