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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The characterization and biological control potential of an endemic entomopathogenic nematode and its symbiotic bacterium through behavioural, molecular and genomic approaches

Soobramoney, Lee-Anne Odelle January 2016 (has links)
A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. Johannesburg, 2016. / The entomopathogenic nematodes (EPNs) have emerged as an important group of insect pests. The EPNs which comprise the Steinernema genus share symbiotic associations with Xenorhabdus bacteria. This research project focused on isolating and characterizing a novel and indigenous EPN isolate with its associated bacteria. The biological control potential of the nematode was investigated in the areas of host infectivity, infective juvenile recovery and progeny yield. These processes were investigated at three different factors. These included time, population size and temperature. The infectious abilities of the symbiotic bacteria were also evaluated without the contributions of the nematode partner at different bacterial doses, time intervals and temperature regimens. The genome of the bacteria was thereafter acquired through whole-genome sequencing and annotation techniques to elucidate the virulence mechanisms and genes involved in temperature adaptation. The species isolated in this investigation was novel. The species shared an 85 % maximum identity to and taxonomically grouped with the species Steinernema khoisanae. The two species shared a common ancestor but the extended branch length of the species under investigation substantiated its novelty. The EPNs infected hosts at different time intervals, population densities and temperature regimens. However, the EPNs performed these processes to different extents. Host mortality significantly increased with time. The EPNs also infected insect hosts at the two experimental temperatures. However, host mortality was higher at the temperature regimen of 20° C and lower at 30° C. Host infections were not significantly different at two tested population densities of 500 and 1000 infective juveniles. The levels of interaction between temperature and time and temperature population density were not statistically significant. The subsequent biological process of recovery was evaluated. The EPNs recovered at both population densities and temperature regimens. The infective juvenile recoveries were statistically insignificant at both population densities and temperature regimens. Since recovery was based on the mere presence of progeny infective juveniles, the percentages were high which contributed to the statistical insignificant findings. This also contributed to the non-significant interaction between population density and temperature. The last biological process investigated was the progeny yield of infective juveniles. The yields were significantly different between both population densities of infective juveniles and temperature regimens. Higher yields were obtained at the temperature regimen of 20° C and 25° C. Lower yields were obtained at 30° C. The unexpected finding was higher progeny yields obtained from the lower population densities of infective juveniles. This contributed to the significant interaction present between population density and temperature. The bacteria were thereafter molecularly characterized. The symbiotic bacteria shared a 99 % sequence similarity to the species Xenorhabdus sp. strain GDc328. It was interesting to observe the infectious abilities of the bacteria without contributions from the EPNs. This study was measured at different bacterial doses, time intervals and temperature regimens. Host mortality was achieved without contributions from the EPN. Host mortality significantly increased with bacterial dose and time. Host mortality was also significantly different between each temperature regimen. Higher mortalities were observed at 30° C and lower mortalities were observed at 20° C. The differences in the performance between the EPN-bacterial partnership and the bacteria alone were attributed to the manner in which adaptation occurred. Since the EPN-bacteria existed as a bi-partite entity, the partners evolved as a bi-partite complex. The bacteria were removed from the symbiosis and cultured individually. External factors may have re-shaped the performance of the bacteria at the different temperature regimens. To further understand the genetic mechanisms of temperature adaptation, host infectivity and symbiosis, the draft whole genome sequence of the bacteria was then acquired. The genome of the bacteria comprised several genes which encoded the flagella system of the bacteria. Also pairs of co-localized toxin-antitoxin genes were discovered. Temperature acclimatization was performed through different cold and heat shock proteins and lastly several molecular chaperones. The studies showed that the species Steinernema spp. and its associated symbiotic bacteria Xenorhabdus sp. strain GDc328 were good bio-pesticide candidates for application against endemic insect pests. / LG2017
2

Biological control of gastrointestinal nematodes of small ruminants, using Bacillus thuringiensis (Berliner) and Clonostachys rosea (Schroers).

Baloyi, Mahlatse Annabella. January 2011 (has links)
Gastrointestinal nematode parasites cause great losses in the production of small ruminants through reduced productivity and the cost of preventive and curative treatments. Because of the threat of anthelmintic resistance, biological control of sheep nematodes has been identified as an alternative to anthelmintic drugs. Bacillus thuringiensis (Bt) (Berliner) and Clonostachys rosea (Schroers) have been widely studied as biocontrol agents. B. thuringiensis has been used for the biocontrol of insects and C. rosea has been successfully used as biocontrol agent of Botrytis cinera (De Bary) in plants. B. thuringiensis and C. rosea strains were isolated from soil collected from the Livestock Section at Ukulinga Research Farm, University of KwaZulu Natal, Pietermaritzburg. Twenty-five strains of Bt and 10 strains of C. rosea were successfully isolated. The Bt colonies were identified by their circular, white, flat and undulate character, and the gram-positive and rod-shaped endospores. C. rosea was identified by white colonies on Potato-dextose agar and the characteristic conidiophores, which were branched and showed phialides at the tips. In vitro screening of the isolates was undertaken to select the best isolates. The isolates that caused significantly greater mortality were Bt isolate B2, B10 and B12 and C. rosea isolates P1, P3 and P8. These isolates caused substantial nematode mortality in both faeces and water bioassay. Nematode counts were reduced by 28.5% to 62% and 44% to 69.9% in faecal bioassay for Bt and C. rosea, respectively. In the water bioassay, nematode counts were reduced by 62% to 85% for Bt and by 62.7% to 89.3% for C. rosea. The best inoculum level at which the best isolates were most effective, and the optimum frequency of application were determined. The trial was conducted using bioassays with faeces and water. Inoculum levels of 10(6), 10(8), 10(10), 10(12) spores ml-1 for Bt and 10(6), 10(8) and 10(10) conidia ml-1 for C. rosea was used in the faecal bioassay. The inoculum levels tested in water bioassay were 10(6), 10(8), 10(10) and 10(12) spores ml-1 for Bt and 10(9), 10(10), 10(11), 10(12) conidia ml-1 for C. rosea. In the faecal bioassay, B2 was the most effective Bt isolate at an inoculum level of 10(10) spores ml-1. Isolate P3 was the best C. rosea isolate at 10(8) conidia ml-1. In the water bioassay, Isolate P3 caused a mortality of 85% at inoculum levels of 10(9), 10(10) and 10(11) conidia ml-1. The performance of biological control agents in the field is sometimes inconsistent. Combining different biocontrol agents may be a method of improving their reliability and performance. However, the combination of most of the isolates was antagonistic, with efficacy less than that of either individual biocontrol agent. In particular, Isolate P3 was more effective when used alone than when combined with any other isolates. Therefore, the combination of biocontrol agents does not always result in synergistic interaction. There were some additive interactions between two bacterial isolates, and with one bacterial and fungal combination. The effect of feeding the best of the biocontrol agents, or diatomaceous earth (DE), was evaluated in sheep. Two doses of Bt (1g and 2g kg-1BW) and C. rosea (1g kg-1BW) reduced the numbers of L3 nematode larvae in sheep faeces. The DE product (at 15% of feed) also reduced L3 numbers but it was less effective than either the Bt or the C. rosea products. Nematode counts were reduced by 74.6%, 75.1%, 84.6%, 68.5% and 27.5% for Bt 1g kg-1BW, Bt 2g kg-1BW, C. rosea (1g kg-1 BW), DE and control, respectively. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.
3

Role of apolipophorin-III in the immediate antibacterial responses of Galleria mellonella larvae (Lepidoptera:Pyralidae)

Halwani, Adla E. January 1999 (has links)
Apolipophorin-III is a hemolymph protein known for its role in lipid transport. Apolipophorin-III isolated from the hemolymph of last instar larvae of Galleria mellonella bound to the surface of the insect pathogenic Gram-negative bacterium Xenorhabdus nematophilus and to the lipid A moiety of its lipopolysaccharide. This binding reduced the toxicity of the lipopolysaccharide to hemocytes and decreased the inhibitory effect of the lipopolysaccharide on phenoloxidase. Apolipophorin-III also bound to the Gram-positive bacterium Micrococcus lysodeikticus; this enhanced the activity of hen egg lysozyme on the organism as well as the lytic activity of G. mellonella cell-free hemolymph. / The involvement of apolipophorin-III in the immune responses of G. mellonella larvae to lipoteichoic acids, surface components of Gram-positive bacteria, was examined. Lipoteichoic acids from Bacillus subtilis, Enterococcus hirae and Streptococcus pyogenes caused a dose- and time-dependent drop in the total counts of circulating hemocytes and a partial or complete depletion of plasmatocytes depending on the species of lipoteichoic acid. All lipoteichoic acids tested activated phenoloxidase in vitro; however, in vivo, only B. subtilis lipoteichoic acid elevated the phenoloxidase activity while the other two suppressed it. Binding of apolipophorin-III to lipoteichoic acids was demonstrated. Apolipophorin-III prevented the complete depletion of plasmatocytes and depressed the activation of phenoloxidase by lipoteichoic acid from B. subtilis. The concentration of apolipophorin-III in hemolymph two hours post injections of lipopolysaccharides or lipoteichoic acids into larvae of G. mellonella did not change with respect to control insects that received phosphate-buffered saline. The concentration of apolipophorin-III in hemolymph at the end of the feeding larval stage was 8--12 mg/mL of hemolymph. Apolipophorin-III was present in significant amounts in the prepupal, pupal and adult stages. The protein was detected immunologically in hemocyte lysates, plasma and fat body. Non-denaturing polyacrylamide gels and immunoblots of fresh hemolymph suggested that apolipophorin-III is associated with a 77 kDa protein.
4

Spatial and temporal dynamics of entomopathogenic nematodes

Fairbairn, Jonathan Paul January 2001 (has links)
The life-history and infection parameters of the entomopathogenic nematodes Steinernema feltiae (Filipjev)(Nematoda:Rhabditida) and Heterorhahditis megidis (Poinar, Jackson & Klein)(Nematoda:Rhabditida) were examined to provide specific details for the construction of mathematical SI models for biological control of soil insect pests. Laboratory experiments using the Greater Waxmoth, Galleria mellonella as the model host were undertaken to specifically examine the transmission behaviour of infective juvenile nematodes. The proportion of infective juveniles of S. feltiae which infected hosts was dependent on time. Previous studies declared that the proportion of infective juveniles which can infect is static, however, over a period of 5 days most of the infective juveniles infected hosts, demonstrating that the proportion infecting is dynamic. Infection of hosts by both species of nematode was compared using two mathematical representations of the transmission rate. Whereas the most parsimonious form of transmission for H. megidis was the linear Mass Action function, it was evident that, when measured at the individual nematode scale, S. feltiae transmission was non-linear. I postulated that this functional difference is due to the biology of the two species of nematodes. The subsequent effect of including the non-linear response on model predictions were investigated and it was demonstrated that the dynamics of the host nematode interaction became less stable. Spatial models of S. feltiae infection were parameterised from laboratory experiments, and control prediction of these models examined. The horizontal rate of dispersal through sand columns was determined in the presence and absence of hosts. Infective juveniles were found to disperse preferentially towards hosts. The predicted dynamics of pest control using the spatial moqel were highly dependent on the degree of nematode dispersal, host dispersal and the attraction of nematode infective juveniles towards hosts. The overall findings of this thesis have been placed in the context of epidemiological models created elsewhere, and predict that entomopathogenic nematodes may be targeted to specific pest systems with a high degree of success. An understanding of the infection biology of these nematode species is crucial in determining how and when pests may be controlled, and equally importantly, which systems successful control is not predicted.
5

Kill Livestock Pests

Roney, J. N., Lane, Al 03 1900 (has links)
This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.
6

Kill Livestock Pests

Roney, J. N., Lane, Al 03 1900 (has links)
This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.
7

Metazoan parasites and health of selected cyprinids at Nwanedi-Luphephe dams

Mbokane, Esau Mathews January 2011 (has links)
Thesis (M.SC. (Aquaculture)) --University of Limpopo, 2011 / The present MSc dissertation emanates from seasonal surveys conducted by the fish parasitological group of the Department of Biodiversity and Aquaculture Research Unit of the University of Limpopo, Turfloop Campus. The first part of the present study was aimed at investigating the metazoan parasites of three cyprinids occurring in the Nwanedi-Luphephe Dams. The main purpose of it was to determine temporal changes in the intensity of infestation in terms of prevalence, mean intensity and abundance of parasite species parasitizing the cyprinids studied over a two year period. Ecological parameters including species host-specificity, seasonality, and gender preference and host size versus species intensity are discussed for each parasite. Altogether 152 specimens were examined for parasites and a total of 2 432 metazoan parasites of ten species were recorded. At the sampling site, all three hosts co-occurred, however, a substantial proportion of Barbus radiatus was collected from the perennial stream feeding one of the twindams. Fish were sampled by means of gill nets and electrofishing or seine netting in accordance with the habitat conditions. Hosts were killed and organs investigated for metazoan parasites. After collection of parasites, standard methods for processing individual parasites were followed. The results obtained revealed the following groups of parasites; monogeneans (ectoparasites) included Dactylogyrus spinicirrus, D. afrolongicornis afrolongicornis, D. afrolongicornis alberti, Afrodiplozoon polycotyleus, Gyrodactylus sp., and Dogielius sp. (all recorded from the gills); Crustacea, Dolops ranarum was found from the mouth cavity, gills and skin of Labeobarbus marequensis. Of these, only two specialists, both monogeneans, were found on Barbus trimaculatus namely, D. afrolongicornis afrolongicornis and D. afrolongicornis alberti. Based on morphology of the haptoral hard parts, these two species were almost similar to each other than to D. spinicirrus. The appreciable difference between D. afrolongicornis afrolongicornis and D. afrolongicornis alberti was mainly in the shape of the marginal bar. Both D. spinicirrus and A. polycotyleus were widely distributed and recorded on the gills of all hosts during all seasons. Both species were recorded for the first time on B. radiatus. Also, D. spinicirrus was recorded for the first time on the gills of B. trimaculatus. Based on comparison with the original material, the species could be identified to species level. These analyses provided sufficient evidence for restoration of Afrodiplozoon polycotyleus as a valid taxon. The existence of two species, Gyrodactylus sp. and Dogielius sp. were recorded for the first time on B. radiatus in South Africa, and this possibly represents new species. The endoparasites included the following groups: digeneans- Diplostomulum metacercariae from the eyes of Lb. marequensis, Ornithodiplostomum sp. and black spot (grubs) were recorded from B. trimaculatus. The latter was also recorded in the muscle of B. radiatus. Unidentified digenean cysts were recovered from the gills and in the body cavity of both Lb. marequensis and B. trimaculatus; nematodes were represented by Contracaecum larvae in the body cavity of both Lb. marequensis and B. trimaculatus; cestodes were represented by gryporynchid larvae from the intestine of B. radiatus. The general high prevalence and intensities of ectoparasites recorded is an indication that the Nwanedi-Luphephe Dams has a biotic mechanism which might have enabled it to sustain the growth rate of ectoparasite intra-population. There was no correlation between either fish length or condition factor and the number of parasites. The study indicated that the abundance of monogeneans is partly influenced by season and that of endoparasites was principally governed by the presence of intermediate hosts and definitive hosts. The second part of this dissertation dealt with the health status of Lb. marequensis. Fish health was assessed using condition-related indices including condition factor and a modified Health Assessment Index (HAI) and the associated Parasite Index (PI). The HAI was performed to determine and examine any macroscopic abnormalities regarding external features and internal organs. The purpose of combining the two indices was to use the infestation of the metazoan parasites found on and/or in Lb. marequensis to determine whether or not the environment they live in was healthy. Both indices together with the condition factor provided relatively simple and rapid indications of how well fish were coping in their environment. The HAI score varied amongst the four sampling seasons. The highest individual mean value was 63 in winter, followed by a score of 50 in autumn, while the lowest were 42 and 33 in summer and spring respectively. To authenticate the HAI and PI data, certain water quality variables were measured and are discussed in detail in this dissertation. The Nwanedi-Luphephe Dams are generally believed to have good water quality. This was supported in this study; conditions assessed in fish using the aforementioned indices did not differ greatly between seasons, nor did the conditions deviate appreciably from normality. The HAI values were low overall which signifies a healthy fish profile for the system. The present investigation showed the existence of differences in the occurrence of individual parasite to be linked to water temperature changes. Thus, seasonal changes do influence parasite developmental stages to a certain degree. Tested heavy and trace metals were within the permissible limits as provided by the Department of Water Affairs and Tourism (DWAF, 1996).
8

Integrated control of gastrointestinal nematodes of sheep using plant extracts. and bicontrol agents.

Ahmed, Mawahib Alhag Ali. 29 November 2013 (has links)
Infection of small ruminants by gastrointestinal nematodes (GIN) is a major health concern because they cause substantial economic losses, especially in the tropics and sub-tropics. For many years, control of GIN has been based upon use of anthelmintics. However, there is now a global challange because mutant GIN individuals can tolerate most of the widely used anthelmintics. Therefore, alternative control measures are needed. The objective of the study was to screen a number of plant species for their anthelmintic effects, and to evaluate selected strains of Bacillus thuringiensis (Berliner) and Clonostachys rosea (Schroers) for activity against sheep GIN. Subsequently, the combined treatments would test a dual control strategy for nematodes by using a combination of plant extracts with biocontrol agents. Ethanol extracts of 25 plant species were screened for their anthelmintic effects against Haemonchus contortus (Rudolphi 1803). Extracts of each plant were used in vitro at various concentrations (10, 20 and 30%) to treat 10 day faecal cultures. Five plants with high efficacies (Ananas comosus L. Merr., Aloe ferox Mill., Allium sativum Linn., Lespedeza cuneata Dum. Cours. and Warburgia salutaris Bertol.f. Chiov) were selected for further investigation, using ethanol, dichloromethane and water extracts at four concentrations (2.5, 5, 10 and 20%). Ethanol was the most effective solvent. Larval counts decreased as a result of increasing extract concentrations. An ethanolic extract of Lespedeza cuneata caused more than 70% mortality at all concentrations. In an in vivo study, the five plants A. comosus, A. ferox, A. sativum, L. cuneata and W. salutaris extracts were compared to a positive Control (Equimax®, a modern anthelmintic based on abamectin and praziquantel). Gender, eggs count (EPG₀) and initial body weights were used in assigning sheep (24 females and 24 males) to six groups. Each group was randomly assigned a treatment. Plant extracts were applied as an oral dose (100 mg kg⁻¹ BW), one dose per week per animal for 42 days (Phase 1). Subsequently, the same sheep were dosed for three consecutive days with the same treatments, keeping them in the same groups (Phase 2). Rectal faecal samples were taken for counting of eggs per gram of faeces (EPG) and L₃ larvae per gram (LPG) in faecal cultures. With application of plant extracts, the EPG count decreased with time (P<0.001), and the impact of the plant extracts increased (P<0.001) with time. Two extracts, from A. comosus and L. cuneata, were the most effective in Phase 1 (58% and 61% reduction of EPG, respectively,), and in Phase 2 (77% and 81% reduction of EPG, respectively). In a study on potential biocontrol agents, two strains of Bacillus thuringiensis (Bt) and one of Clonostachys rosea f. rosea (C. rosea), and compared with a diatomaceous earth (DE) product for their anthelmintic activity in sheep. Bacillus thuringiensis and C. rosea were fed to sheep at a rate of 1g kg⁻¹ BW, and DE was fed at 2% of sheep diet. The biocontrol treatments had no effect on EPG (P>0.05), but reduced GIN larvae per gram (LPG) (P<0.001) in faecal culture. Efficacy varied with time (P<0.001). By Day 7 Bt, C. rosea and DE had caused mortalities of GIN of 75.7, 86.9 and 60.6%, respectively. In addition, the efficacy of feeding 1g kg⁻¹ BW of C. rosea chlamydospores to sheep every day, every second day and every third day was tested. Daily feeding of fungal chlamydospores reduced LPG (a count of 12±1.67 GIN larvae) (P<0.001) more than feeding them the biocontrol agent every second day (39±0.77) or third day (58±1.77). By Day 12, feeding the biocontrol agent to sheep every day, every second day, or every third day caused mortality of GIN larvae of 90, 63 and 49%, respectively. Four dietary levels (treatments) of C. rosea (0.25g (F1), 0.5g (F2), 1g (F3) and control (C) of C. rosea product kg-1 BW) were tested. Treatments were each mixed with a complete diet and fed to sheep once daily for 10 weeks, according to body weights. Increased doses of the biocontrol agent reduced LPG (P<0.001), larval development (LD) (P<0.001), and increased efficacy (P<0.001). On Day 70, F1, F2, F3 and the Control controlled LD by 33.3, 72.3, 89.4 and 2.6%, respectively. Clonostachys rosea was effective in reducing third stage larvae (L₃) on pastures significantly (P<0.001) by Day 63 and Day 70. Ethanolic extracts of A. comosus, A. ferox, A. sativum, L. cuneata and W. salutaris all reduced egg production by GIN parasites of sheep. Feeding sheep cultured chlamydospores of a biocontrol fungus, Clonostachys rosea, reduced counts of nematode larvae in sheep; and 1g C. rosea chlamydospores kg⁻¹ BW daily was enough to reduce nematode infective larvae, therefore reducing the degree of pasture contamination. An initial trial showed that the combination of the two treatments of an A. comosus extract and C. rosea chlamydospores was more effective than either treatment on its own in controlling gastrointestinal nematodes in sheep. A long-term trial is being undertaken currently to confirm this finding. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.
9

Integrated system for the management of meloidogyne javanica in potato production

Seshweni, Mosima Dorcus January 2016 (has links)
Thesis (M. Agricultural Management (Animal Production)) -- University of Limpopo, 2016 / Cultivated potato (Solanum tuberosum L.) cultigens do not have resistant genotypes to root-knot (Meloidogyne species) nematodes. Currently, efforts are underway to introgress nematode resistance in potato breeding programmes, whereas other environment-friendly nematode management strategies are being assessed in various cultigens. Nemafric-BL and Nemarioc-AL phytonematicides have being researched and developed for managing the root-knot nematode whereas Biocult Mycorrhizae are intended to enhance crop productivity through improved absorption of P, which is inherently low in most South African soils. The objectives of the study, therefore, were: (1) to determine the interactive effects of Nemacur (N), Biocult Mycorrhizae (B) and Nemarioc-AL or Nemafric-BL phytonematicide (P) on population densities of M. javanica and growth of potato plants, (2) to investigate the effects of Nemacur (N), Velum (V), Biocult Mycorhizae (B) and Nemarioc-AL or Nemafric-BL phytonematicide (P) on population densities of M. javanica and growth of potato plants. For the microplot experiment, potato cv. ‘Mondial G3’ seeds were sown in 25 cm-diameter plastic pots with 5 000 ml steam-pasteurised river sand and Hygromix-T at 3:1 (v/v) growing mixture in autumn (March-May) 2015. Pots were buried 80% deep into the soil in with 0.5 m inter-row and 0.5 m intra-row spacing. Potato cv. ‘Mondial G3’ seeds were dipped in a mixture of Mancozeb with a wettener for disease management prior to sowing. Appropriate treatments were applied soon after emergence of leaves. Each plant was inoculated by dispensing a mixture of 5 000 eggs and M. javanica J2. Eight treatments, control (N0B0P0), Nemacur (N1B0P0), Biocult (N0B1P0), phytonematicide (N0B0P1), Nemacur × Biocult (N1B1P0), Nemacur × phytonematicide (N1B0P1), Biocult × phytonematicide (N0B1P1) and Nemacur × Biocult × phytonematicide (N1B1P1), were arranged in a randomised complete block xxvi design (RCBD) with 8 replications (n= 64). Under field conditions the study was conducted in summer (October 2015 - January 2016), with 30-cm furrows dug and potato seeds placed in the soil with 30 cm inter-row and 40 cm intra-row spacing. The four treatments, namely, (1) untreated control, (2) Nemacur or Velum (3) Biocult Mycorrhizae and (4) Nemarioc-AL or Nemafric-BL phytonematicide, were arranged in RCBD, replicated three times for the Velum experiment and five times for the Nemacur experiment. At 56 days after inoculation, the second order interaction (N1B1P1) was highly significant (P ≤ 0.01) for eggs in root and total nematodes, contributing 13 and 12% to total treatment variation (TTV) of the two variables, respectively, in the Nemarioc-AL phytonematicide study. Relative to untreated control, the second order interaction (N1B1P1) reduced eggs in root and total nematodes by 42 and 36%, respectively. In both Nemarioc-AL and Nemafric-BL phytonematicide experiments, the combination of phytonematicide and Biocult Mycorrhizae reduced gall rating. Nemacur, Biocult and Nemarioc-AL phytonematicide, the treatment effects were highly significant on eggs, J2 in root and total nematodes, contributing 53, 68 and 57% to TTV of the three variables, respectively. Nemacur, Biocult and Nemafric-BL phytonematicide treatments each was not significant (P ≤ 0.05) for nematodes variables. Both treatments for Nemacur, Biocult and Nemarioc-AL or Nemafric-BL phytonematicides were significant for gall rating, contributing 92 and 70% to TTV of the variable, respectively. In Nemarioc-AL phytonematicide, relative to the untreated control, gall rating was reduced by 48 to 56%, whereas in Nemafric-BL phytonematicide the variable was reduced by 33 to 56%. In the Velum study, Biocult and Nemarioc-AL or Nemafric-BL phytonematicide, the treatment effects in both experiments were highly significant (P ≤ 0.01) on eggs in root, contributing 88% to TTV of the variable. Both treatments from Nemarioc-AL xxvii and Nemafric-BL phytonematicides had no significant effects on all plant variables measured. In microplot, the second order interaction (Nemacur × Biocult × Nemarioc-AL phytonematicide) was highly significant for nematode eggs in root and total nematode. In a three-way matrix, the N1B1P1 interaction had the highest effects on eggs, followed by Biocult alone, then Nemacur alone and then the phytonematicide. The same trend was observed in the three-way matrix for total nematodes. However, in two-way matrix for eggs, Biocult outperformed Nemacur, as was the phytonematicide on J2. In another microplot study, the second order interaction (Nemacur × Biocult × Nemafric-BL phytonematicide) was significant for J2 in soil and roots, with the three-way matrix showing, that Biocult alone had higher effects than the N1B1P1 interaction on J2 in root. A three-way matrix also showed that Nemacur was outperformed by the phytonematicide alone, Biocult alone and the interactions on J2 in soil. In conclusion, Nemarioc-AL and Nemafric-BL phytonematicides could each be used with Biocult Mycorrhizae in the management of population densities of M. javanica in potato production since the impact from Nemacur which is a synthetic nematicide does not have that much difference from that of phytonematicides interacted with Biocult Mycorrhizae. / Agricultural Research Council

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