Incognita Larvae Research Articles

Nematicidal Effects of Various Fractions of Curcuma longa against Meloidogyne incognita (root knot nematodes)

Parasitism is an important limiting factor responsible to cause damage to agricultural production. Plant parasitic root knot nematodes attack several economic crops in Pakistan. Plant- parasitic nematodes considerably add huge losses to economies in the top tomatoes crop producing countries throughout the world, instead of controlling the main pathogenic nematode species as usual; one of the innovative strategies to control plant-parasitic nematodes would be to manage diversity in communities in order to lead them to be less pathogenic. The plants and their materials are one of the potential remedies for nematodes management. Turmeric (Curcuma longa) along with its several biological applications may serve as a biopesticide against Meloidogyne incognita, a nematode species. A bioassay guided isolation of various fractions of turmeric was subjected to nematicidal activity in comparison with Azadirachta indica against Meloidogyne incognita larvae at the concentration of 0.25, 0.5, and 1% for 48 hours. Alongside, Larvae and eggs of nematodes were inoculated around the tomato seedlings in experiments with turmeric in a growth chamber. The control contains water instead of turmeric. Root gall severity and final nematode population were suppressed significantly. It was observed that the use of turmeric is very important for selected plant parasitic nematodes management.

Animal Biomedicine Controls Root Knot Disease in Lentil Callus Culture: Enriched Advanced Clinical Toxicology Socio Economy Science Technology Communication by Preventing 21st Century COVID-19 Like Pandemic Diseases

The economic pulse seeds, Lens esculentum L. Cv. ‘Asha’ root callus develop on Murashige and Skoog (MS)-media supplemented with 2 mg/1, 2,4-D (2,4-dichloro phenoxy acetic acid) and inoculated with Meloidogyne incognita larvae (65 ± 2 J2) in the culture tube to study their multiplication rate under sterilized condition in the tissue culture laboratory, and biomedicine-nematode extract (NE) prepared from M. incognita females, when applied at 1.3mg/culture tube to root callus of lentil, reduced nematode infestation of callus and improved callus growth. This animal biomedicine-NE is thought to induce defense-resistance in lentil root callus and may prevent 21st –century pandemics like virus diseases by boosting immunity, resisting toxic effects, and improved biomedicine, advanced in clinical toxicology, green-socio-economy, science technology, and communication application. The biomedicine-NE not only increase agriculture and crop production but also enable the development of a new-generation of nanotechnology-agrochemicals reducing negative-environmental-impacts and maintaining-crop-yields. And both; biomedicine-NE and pulses may itself focus on nanoformulation of agrochemicals and other nanotechnological interdisciplinary future nanotoxicology research and applications in agriculture, and interaction nanomaterials-NE with plants, their environment, and other organisms also.

Nematicidal potential of nematophagous fungi on Meloidogyne incognita

The efficacy of indigenous fungi isolated from mite,grub,teabark and soil sample were tested against Meloidogyne incognita for their efficacy in vitro through egg hatch inhibition, J2 mortality and egg parasitism. Mortality of M. incognita larvae was found to be directly proportional to concentration of culture filtrate of the isolates and duration of exposure in vitro. Among the isolate listed, Isolate 8 showed highest egg hatch inhibition, juvenile mortality and egg parasitism of M. incognita. followed by Isolate 10, Isolate 1 and Isolate 2.

Phytotoxic and nematicide evaluation of Croton ehrenbergii (Euphorbiaceae).

Within its natural habitat, Croton ehrenbergii exhibits an innate defense mechanism that is not seen in other plants; it grows unharmed amidst predators and nature, while other species perish. In light of its capacity for defense, C. ehrenbergii was evaluated to better understand the scope of its phytotoxic and nematicide properties. To assess this, fractions obtained by bipartition of a hydro-alcoholic extract, and l-quebrachitol, the main constituent of C. ehrenbergii, were evaluated on Lactuca sativa (dicotyledon) and Lolium perenne (monocotyledon) seeds. Additionally, bipartition fractions and l-quebrachitol were evaluated on a population of Meloidogyne incognita for their nematicide activity. From this phytochemical research, l-quebrachitol (1), phenylalanine (2), trans-4-hydroxy-N-methylproline (3) and the flavonoids: kaempferol (4), tiliroside (5), nicotiflorine (6) and rutin (7) were identified by spectroscopic analysis. Both methanol and hexane fractions from aerial parts of the plant inhibited the germination and elongation of roots and stems in L. sativa, but not in Lolium perenne, showing that these fractions mostly inhibit the dicotyledon species used in this research. l-Quebrachitol showed slightly higher seed germination inhibition for Lolium perenne in comparison with L. sativa. Three of the fractions evaluated showed nematicide activity against Meloidogyne incognita larvae (J2) at the 48 h benchmark, compared with carbofuran. l-Quebrachitol shows higher mortality after 48 h exposure at a lower concentration than carbofuran. A variety of compounds were isolated from this research, some were common within the Croton genus (4-7), whereas others were not (1-3). This is the first phytochemical, phytotoxic and nematicide report on C. ehrenbergii. Methanol and hexane fractions from the aerial parts of C. ehrenbergii and l-quebrachitol could be used as alternative natural herbicides, predominantly against dicotyledon weed seeds. All fractions had a good mortality percentage against J2 Meloidogyne incognita larvae. © 2019 Society of Chemical Industry.

Nematicidal activity of Paecilomyces lilacinus 6029 cultured on Karanja cake medium

Antagonistic fungi parasitize root-knot nematodes through secretion of extracellular hydrolytic enzymes and secondary metabolites. In present study, in vitro bioassay showed that Paecilomyces lilacinus 6029 culture filtrate from Karanja cake medium killed 100% Meloidogyne incognita larvae while only 78.28% mortality was recorded by Czapeck-Dox filtrate within 12 h of exposure. The filtrate, irrespective of culture medium, was found to be more nematotoxic when incubated for 15 days. Fourier Transform infrared spectroscopy predicted the presence of phenolic and alcoholic compounds in the filtrate. Furthermore, the active metabolites in fungal filtrate were partially characterized. pH stability test revealed that nematotoxicity of the filtrate appeared at all range of pH with low pH filtrate possessing more toxicity against M. incognita. Interestingly, buffers of same pH value did not show any nematicidal effect. No significant difference in nematicidal activity was observed between boiled (98.2% mortality) and unboiled culture filtrate (100% mortality). Ethyl acetate and lyophilized aqueous extracts produced higher nematicidal activity than a hexane extract indicating polar nature of active compounds produced by P. lilacinus 6029.

Effects of the Storage Temperature of Soil on Number of Meloidogyne incognita Larvae Extracted by Baermann Funnel Method

Effects of the Storage Temperature of Soil on Number of Meloidogyne incognita Larvae Extracted by Baermann Funnel Method

Relative efficacy of different cropping sequences integrated with ploughing for the management of plant parasitic nematodes: Relative wirksamkeit verschiedener beim pflügen integrierter fruchtfolgen zur bekämpfung von pflanzenparasitären nematoden

The relative efficacy of 25 different cropping sequences was tested at the end of the experiment. It appears that for Hoplolaimus indicus sequence number 16, 20, 8 and 10 gave high reduction in rate of reproduction, for Helicotylenchus indicus sequence No. 6, 11, 17 and 3, for Rotylenchulus reniformis sequence No. 2, 8, 13 and 14, for Tylenchorhynchus brassicae sequence No. 6, 24, 3 and 13, for Meloidogyne incognita larvae sequence No. 1, 2, 4 and 24, for Pratylenchus coffeae sequence No. 1, 2, 3 and 5; for Tylenchus filiformis sequence No. 2, 3, 4 and 5.

Effects of Inoculum Level and Time of Microcoleus vaginatus on Control of Meloidogyne incognita on Tomato

Application of Microcoleus vaginatus, a blue-green alga (Cyanobacterium) at different levels along with Meloidogyne incognita, second stage larvae, in the rhizosphere of tomato plants; showed that the plant growth as well as yield of tomato were increased and gall formations and nematode populations decreased with the increase in inoculum level of M. vaginatus. An inoculum level of 20 ml endospores suspension of M. vaginatus (2.4 × 10 6 endospores per ml) per plant was optimum to reduce nematode attack with a population density of 1000 larvae per kg soil. Plant growth and yield of fruits were greatly suppressed and gall formations on roots, and nematode populations in soil were increased when M. incognita larvae added five days prior to M. vaginatus inoculation. On the other hand, when M. vaginatus inoculated ten days before nematode inoculation, suppressive effect of M. incognta on plants was reduced and their population density as well as gall formations were also decreased significantly. The efficacy of simultaneous inoculation of both nematode and M. vaginatus was lied in between two treatments discussed above.

The influence of Meloidogyne incognita on the growth, physiology and nutrient content of Phaseolus vulgaris

One-week-old Phaseolus vulgaris cv. Topnotch Golden Wax plants were inoculated with 0, 1000, 5000 or 10 000 freshly hatched Meloidogyne incognita larvae per plant, and maintained under controlled conditions (21 °C, 14 h day at 400 μE m −2s −1; 16 °C, 10 h night cycle). At 3 weeks after inoculation, leaf area, dry weight, number of flowers, the total carbon, hydrogen, nitrogen, calcium, copper, iron, manganese, potassium and zinc content of shoots and roots, leaf chlorophyll content, and dark respiration and photosynthetic rates were measured. Respiration rate, percentage shoot nitrogen content, and calcium, copper and iron content (per unit weight and on a shoot: root ratio basis), were significantly increased with increasing inoculum level. Other measured parameters were significantly decreased. Calcium, copper and iron in the shoot and potassium in the root increased per unit weight, while copper and zinc in the roots decreased significantly as a result of nematode infection. However, the overall total content of the nutrient elements per plant was significantly decreased by nematode infection. Differences in the physiology and nutrient content of P. vulgaris plants, as they relate to altered growth and loss of yield of nematode-infected plants, are discussed.

Changes Induced by Meloidogyne incognita in Superoxide Dismutase, Peroxidase and Polyphenol Oxidase Activity in Tomato Roots

Summary Inoculation of resistant tomato roots with Meloidogyne incognita larvae resulted into decreased superoxide dismutase and increased peroxidase and polyphenol oxidase activities and higher levels of orthodihydroxy phenolic compounds. Superoxide dismutase activity increased substantially in the susceptible cultivar after inoculation.

Efficacy of Resistance to Root-knot Nematode in Snap Beans1

Abstract Four snap bean (Phaseolus vulgaris L.) breeding lines, resistant PI 165426, and 2 susceptible commercial cultivars were tested for resistance to root galling and root-knot nematode (Meloidogyne incognita (Kofoid & White) Chitwood) reproduction under greenhouse and field conditions. Root gall indices, reproduction indices, and numbers of eggs/g of root were significantly less on resistant lines than on ‘White Seeded Provider’ in 2 greenhouse tests. In field tests, soil treatment with the nematicide DBCP resulted in significant control. In nontreated plots, resistant bean lines had less root galls than ‘Early Gallatin’. Plots planted with resistant lines had fewer M. incognita larvae than those with ‘Early Gallatin’. Mean yield of pods from resistant lines in nontreated soil was about 3 times the yield of ‘Early Gallatin’. Yield of pods from treated and nontreated subplots were not significantly different. These results indicate that resistance is equivalent to soil fumigation for root-knot nematode control in snap beans.

線虫の薬剤感受性実験法としての薬液浸漬法の検討

In order to estimate analytically the susceptibility of nematodes of different stages, an immersion test proposed by Moje (1959) was examined. The standard procedure by the present authors is as follows: 1) to immerse nematodes in the solution of a given chemical for 24 hours 2) remove the solution of the chemical (needed two hours) and store the treated nematodes in sterile water for 22 hours and 3) separate mobile nematodes from the immobile by cotton wool filter for 24 hours and calculate mortality of the nematodes. Temperature during experiments is 25°.As a test nematode, the southern root-knot nematode, Meloidogyne incognita (Kofoid & White) was used. Larvae were obtained from egg-masses or infected soils by Baermann funnel technique or sieving plus Baermann method. It is convenient to use about a hundred nematodes for a treatment. Loss of M. incognita larvae during test process is considered to be about ten per cent. From 70 to 90 % of mobile larvae of M. incognita were isolated by the cotton wool filter specially designed, where the coefficient of the variation was less than twenty per cent in most experiments. The rate of separation reached the maximum within 24 hours. An example is given in Table 1.Storing treated nematodes in sterile water leads them to death or recovery from anesthetization. Relation of procedure to remove EDB emulsion and period for maintaining the nematodes treated with EDB in water, to the mortality of M. incognita larvae is shown in Table 2. Mortality due to 24 hours store was near to that for 46 hours.In most experiments, linear correlation was observed between concentrations in logarithm of EDB and mortality in probit at the level of 95 % confidence, except some lower concentrations (Figs. 2 and 3). Results of experiments conducted by the same person in August, September and October with M. incognita larvae from egg-masses on the roots of sweet potato in the same field are shown in Figs. 2 and 3. The figures indicate the reproductivity in a sense of the experiments by the present method. LC-50 of the nematodes from sweet potato to EDB was 86 and 80 ppm in August (from Figs. 2 and 3), 54 ppm in September and 77 ppm in October (Fig. 2). The relation between temperatures during immersion in EDB emulsion and the mortality of M. incognita larvae was also examined (Table 3).

Influence of Feeding Duration On Moulting and Sex Determination of Meloidogyne Incognita

Second stage Meloidogyne incognita larvae of different sizes were dissected from plant roots and placed in water agar to observe their development. The same population was tested in 1968 and again in 1970. Larvae that had fed for less than 9 days at 22° C were unable to moult, but depending on how long they had fed, older larvae moulted to the third, fourth or fifth stage. Larvae moulted to the third stage at approximately the same age irrespective of feeding duration. Most larvae dissected from roots 10, 11 or 12 days after inoculation in 1968 became male, whereas older larvae became female. There was a strong correlation between mean width of larvae at the time of dissection and their subsequent development. The same population retested in 1970, gave different results. Fully fed second stage larvae were smaller than in 1968 and sex was no longer labile. Larvae that had fed for more than 10 days were female, if they became sexually differentiated at all. As the population had been kept in isolation and was morphologically unchanged, the change in behaviour of the population was probably caused by selection between tests of a line able to become female in poor environmental conditions.

Growth substances in roots of tomato (Lycopersicon esculentum Mill.) infected with root‐knot nematodes (Meloidogyne spp.)

SUMMARYRoots of tomato plants with galls caused by larvae of Meloidogyne spp. contained a similar concentration of auxin as uninfected roots, but a larger total amount because the roots of infected plants were heavier. The body contents and saliva or excretions of M. incognita larvae contained too little auxin to account for the increased amounts in infected roots. Roots with galls contained more bound auxin, released by alkaline hydrolysis or incubation after maceration, and more tryptophan and other amino acids, than uninfected roots. The larvae may hydrolyse the plant proteins to yield tryptophan, which may then react with the endogenous phenolic acids to produce auxin.

A Predacious Soil Turbellarian That Feeds On Free-Living and Plant-Parasitic Nematodes

A small soil rhabdocoel of the class Turbellaria was found preying on Meloidogyne incognita larvae. The rhabdocoels were successfully reared through several generations using larvae of root-knot nematode, and larvae and adults of Panagrellus redivivus. The biology of the flatworm was studied, and its role as a possible biological control agent of plant nematode diseases was investigated.