The efficacy of Paecilomyces lilacinus strain UP1 as biological control agent of Meloidogyne incognita attacking tomato was evaluated under screenhouse condition pot experiments. P. lilacinus was formulated on rice substrate in powder form. Root weight, gall index rating, number of galls, egg masses and nematodes per one gram root sample were determined and per cent reduction in gall number was computed. Root weight and gall index ratings were significantly higher in untreated plants than those with P. lilacinus and with the commercial fungicide Nemacur. Number of galls, nematodes and egg masses per one gram root sample were significantly reduced by the application of P. lilacinus at all levels and this was comparable with Nemacur. However, egg mass count in plants treated with the lowest concentration of the biocontrol agent was not significantly different from the uninoculated control. Per cent reduction in gall number was the highest at treatment with 7.92 × 106 spores per ml of P. lilacinus.
Root-knot nematode Meloidogyne incognita (Kofoid & White) Chitwood is an economically important pathogen of many agricultural crops, and the frequency of occurrence, abundance and importance of this nematode in resource-poor agricultural production systems make control necessary. Field studies were conducted in 2004 and 2005 to determine yield loss of Roselle due to natural infestation by M. incognita using Carbofuran 3G at 2 kg a.i./ha and untreated as check. The yield of Roselle was found to be higher with the application of nematicide-Carbofuran 3G at 2 kg a.i./ha. The percentage increase over control was 48.7 and 40.8% in the years 2004 and 2005, respectively. A significant reduction in the yield of Roselle in untreated plots was mainly attributed to direct damage of the root system by the feeding of root-knot nematode M. incognita. Root-knot nematode population in carbofuran treated plots was significantly lower than in untreated check in the two years, also at harvest. In the check the nematodes multiplied many folds during the cropping season. High nematode population in the untreated check decreased plant growth and ultimately reduced the number of seeds and weight of seeds.
Seeds of local trees, such Azadirachta indica A. Juss, Adenanthera pavonina L., Leucaena leucocephala (Lam.) de Wit and Eucalyptus spp., were used as aqueous extract at 25, 50 and 100 % concentration to control the activity of Meloidogyne javanica (Treub) Citwood. All seed extracts showed lethal effect on M. javanica eggs, and a gradual decrease in egg hatching and an increase in mortality of second-stage juveniles were observed with the increase in extract concentration. L. leucocephala was found to be most effective in reducing egg hatching, whereas 100 % mortality of juveniles was observed in the case of A. indica seed extract. Number of knots was significantly reduced at 100 % concentration when seeds of chick pea and mung bean were treated and soil was drenched with A. pavonina and Eucalyptus spp. seed extract.
The fungicidal and nematicidal activity of an emulsifiable formulation of furfural [2-furancarboxaldehyde] against root rot and root-knot pathogens was studied in laboratory, greenhouse and field experiments. The linear growth of tested soilborne pathogenic fungi was dramatically reduced with the increasing of furfural concentrations added to the growth medium up to 4000 ppm where no growth was observed, while the bacterial and fungal bioagents showed more tolerance to these concentrations and failed to grow at 6000 and 7000 ppm, respectively. Pot and field experiments indicated that furfural at 6000 ppm combined with bioagent treatments proved to have superior suppressive effect against tomato root rot incidence, caused by Fusarium solani and Rhizoctonia solani, comparing with each individual treatment. Numbers of nematodes in soil declined sharply in direct response to furfural application with the sharpest reductions in its population. No symptoms of root-knot incidence, caused by Meloidogyne incognita as well as no detected galls and eggmasess were observed in the root system of tomato plants grown in either artificially or naturally infested soil with the parasite at the same concentration under greenhouse and field conditions. Results from these experiments indicate that a variety of effective broad-spectrum formulations of furfural can be developed for control of economically important soilborne pests.
Two screenhouse experiments were conducted in 2004 and 2005 rainy season to investigate the reaction of three selected Sesamum indicum cultivars against three population densities of a root knot nematode, Meloidogyne incognita. Seedlings of S. indicum were raised in pots arranged in completely randomised design and inoculated with 0, 5 000, and 10 000 eggs of M. incognita, replicated six times. Root knot disease was evaluated at mid-season and harvest. A new method for evaluating and reporting resistance to Meloidogyne spp. that divides the screening procedure into two phases in the same experiment was adapted. The first phase investigated the host response through the traditional standard method that utilises only gall and nematode reproduction indices, while the second considered the effect of root knot disease on grain production of the crop. There was consistency in host designation of E8 and NICRIBEN-01M (syn: 530-1-6) which were classified under the traditional and improved rating schemes as tolerant and resistant, respectively. However, S. indicum breeding line Pbtil (No. 1) which was considered susceptible under the old system was found to be tolerant using the integrated and improved system. Root galls incited by the nematode degenerated significantly from mid-season to harvest time. Utilising yield as additional parameter for assessing resistance to root knot nematode provides a complete picture of Sesamum-Meloidogyne interaction, and therefore a more meaningful system for determining host response.
Leaves, stem and pneumatophore of Avicennia marina and leaves and stem of Rhizophora mucronata were used as the organic amendments at 0.1, 1 and 5% concentrations in the control of root rot fungi like (Fusarium spp., Rhizoctonia solani and Macrophomina phasoelina) and root knot nematode Meloidogyne javanica on potato. In pot experiments, germination of seeds, shoot length, shoot weight, root length, root weight and number of knots were signifi cantly increased when plant parts like leaves, stem and pneumatophore of A. marina and R. mucronata were used at 1 and 5% concentrations. There was a complete suppression in infection of R. solani and M. phaseolina when A. marina and R. mucronata were used at 5% concentration on potato. Maximum inhibition of knots of M. javanica was observed when powder made from mangrove plant parts was used at 1 and 5% concentrations. Powder from all plant parts, like leaves, stem and pneumatophore, was effective in suppression of root infecting fungi and root knot nematode.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.