Control of citrus nematode, Tylenchulus semipenetrans in Nagpur Mandarin Orchard (original) (raw)
Related papers
Three bacterial species of plant growth promoting rhizobacteria (PGPR) namely Paenibacillus polymyxa, Methylobacterium mesophilicum and Methylobacterium radiotolerans were tested alone or combined with humic acid as bio-control agents against the citrus nematode Tylenchulus semipenetrans under laboratory and field conditions. Results cleared that; all tested PGPR species produced IAA, HCN, ammonia, chitinase and protease enzymes and also solubilized phosphate in laboratory. P. polymyxa emphasized the superiority among other species in all PGPR properties except for phosphate solubilization, whereas M. radiotolerans showed highest amount of phosphorus solubilized in culture media. On the other hand, the results of the nematode survey conducted on orange, Citrus sinensis L. cv Balady grown in different localities of Ismailia and Sharkia Governorates during season 2019, revealed the presence of seven genera and species of plant-parasitic nematodes. Among which, T. semipenetrans occurred in all examined samples (100% frequency of occurrence) with a relatively high population density of 2330 and 2640 infected juveniles (J2) /250 g soil in Ismailia and Sharkia Governorates, respectively. Field experiments were conducted in two different locations, at Ismailia and Sharkia Governorates to assess the effectiveness of PGPR strains alone or combined to reduce the numbers of T. semipenetrans during season 2019. It was found that, all treatments caused significant (P≤0.05) reduction in T. semipenetrans population, compared to control treatment. The nematicide, Nemathorin® 10% G followed by P. polymyxa (20 L.fed -1 ) + foliar spraying of M. mesophilicm (5 L.fed -1 ) gave the highest efficacy in controlling the citrus nematode. Percentage reduction in numbers of J2/250g soil and adult females/1g roots for these treatments in Ismailia Governorate were 91% (85.7%) and 91.4% (89.5%), respectively. While the parallel values in Sharkia Governorate were 90% (87%) and 94% (90%), respectively. The combination of P. polymyxa and humic acid (20 L.fed -1 ) with foliar spraying of M. mesophilicm (5 L.fed -1 ) gained the third position. All treatments increased the fruit yield compared to control treatment. The highest percentages of increase were determined with Nemathorin (160% and 206%) followed by P. polymyxa + Humic acid (20 L.fed -1 ) + foliar spraying of M. mesophilicum (155.7% and 193%) and M. radiotolerans + P. polymyxa + foliar spraying of M. mesophilicum (153% and182%) in Ismailia, and Sharkia Governorates respectively.
2010
The citrus nematode is an important nematode that is distributed in citrus gardens worldwide and causes decline and growth reduction of citrus plants. A control way of this nematode is chemical control that it is dangerous to environment. In this research, leaf extract of Allium sativum, Brassica campestris, Capsicum frutescents, Glycyrrhiza glabra, Datura innoxia, Chenopodium botrys and Foeniculum vulgare was used to evaluate them on plant growth and citrus nematode control in Fars province, Iran. In laboratory conditions different plant extracts, concentration of each extract and duration time of exposure extracts was examined in Petri dishes. Results showed that increase in concentration and duration time of exposure extracts caused increased percentage of nematode mortality. In laboratory experiments extracts of A. sativum and C. frutescents, D. innoxia, F. vulgare were more effective respectively. In pod experiments, nematode populations decreased in seedlings that were treated with A. sativum, C. frutescents and F. vulgare compared with control sample. In these, pods increased plant growth. These results confirm that it is possible to use local plant extracts to control citrus nematode instead of using chemical nematicides.
ORIGINAL ARTICLES Effects Of Some Fungi And Bacteria As Bio-Control Agents Against Citrus Nematode
2012
The nematicidal effect of bacterial bio-control agents, i.e. Bacillus subtilis, Pseudomonas fluorescens and Sarratia marcescens and fungal bio-control agents, i.e. Aspergillus niger, Penicillium digitatum, Trichoderma harzianum and Trichoderma viride were examined against Tylenchulus semipenetrans in vitro and in vivo tests. In vitro tests, the effect of cultural filtrates of bio-control agents was evaluated at concentrations of S and/or S/2. All bio-control agents were found to be highly nematostatic against J 2 of citrus nematode. B. subtilis at S concentration was more effective against j 2 of nematode after 72h exposure time, since the nematode mortality % was 100.0%, 99.9% and 99.2% for B. subtilis, S. marcescens and P. fluorescens, respectively. The effect of fungal bio-agents against j 2 was less compared with bacterial bio-control agents. As nematode mortality was 97.6%, 97.0%, 89.4% and 87.8%. For T. viride, T. harzianum, P. digitatum and A. niger, respectively At S concent...
The problems of citrus nematode (Ty/enchulus semipenetran$ C,.abb)in orchards and nurseries of mandarin orange in Darjee1ing hills have been studies during 1988 to 1991. This nematode could be isolated from the infested roo1s and rootzonesoil and the slow decline symptoms could be reproduced in orange through seedling soil inoculation. Citrus nematode occured in all the orchards swveyed but Its incidence differed with respect to the season of observation and physiological condition of the plan1s. The population was high during March-April and low during November-December under Darjee1ing condition. All the common citrus species tested excluding trifoliate orange (poncirus trifoliata) were found to be susceptible to this nematode. Infested seedlings have been found to be an important means of spread which could be controlled by treating the r001s with 200 ppm of thimet (10 g) or nemacur (10 g) for 30 minutes. Nematode population in an orchard may be reduced by applying furadan (3 g) or thimet at the rate of 100 g/tree twice in a year Growing annuals, particularly cabbage, cauliflower, aster, zinnia and marigold etc. in the orchards reduced the nematode population both on the feeder roo1s and in rootzone soil.
PATHOGENICITY OF CITRUS NEMATODE (TYLENCHULUS SEMIPENETRANS) ON CITRUS JAMBHIRI
Citrus nematode (Tylenchulus semipenetrans) causes severe damage to citrus. In the present study the relationship between different initial densities of T. semipenetrans and reduction in growth parameters of Citrus jambhiri and nematode infestations was examined in pot experiment under greenhouse conditions using completely randomized design. Seedlings of C. jambhiri were inoculated with T. semipenetrans at the rate of 0, 1,000, 2,000, 4,000 and 8,000 second stage juveniles/pot in the greenhouse. Data were collected on fresh and dry weights of the shoot and root, shoot length, nematode populations in the roots and soil and reproduction factor. All the data were subjected to analysis of variance and means were compared by Duncan's Multiple Range Test at 5%. The relationships between number of galls and growth variables and nematode infestations were determined using regression analysis. It was observed that all the inoculum densities caused reductions in growth parameters and were found directly proportional to the inoculum density. Similarly, a direct relationship was observed between root and soil populations of the nematode and inoculum levels. On the other hand, the nematode build up was the maximum at lower inoculum level and an inverse relationship was observed between reproduction factor and inoculum densities of the nematode.
Pakistan Journal of Zoology, 2019
The study of the population dynamics of citrus nematode (Tylenchulus semipenetrans) in a production area is required for the assessment of damaging potential of the nematode to citrus, identification of key factors that influence population densities, and to devise effective management strategies. In the present study, seasonal fluctuations in the population densities of T. semipenetrans were studied in two citrus orchards naturally infested with citrus nematode during the year 2014. The effect of soil temperature was also evaluated on the populations of the nematode. The nematode populations differed significantly at both the soil depths. The populations were significantly higher at a depth of 30 cm as compared to 45 cm throughout the year at both the orchards. Similarly, females per gram of roots also followed the same pattern. The number of nematodes in the soil and females in the roots were the higher during the months of April to June and August-September showing two peaks throughout the year. The regression analysis between temperature and number of nematodes in the soil and females in the roots showed highly significant results at both the orchards. A direct relationship was observed between nematode population and temperature. Maximum nematode and female populations were observed at a temperature ranging between 26°C to 29°C at a soil depth of 30 cm. On the other hand, minimum populations were recorded at a temperature range of 9°C to 12°C. Similar trends were observed at the soil depth of 45 cm. It is concluded from the present study that the management of nematode including application of nematicides should be started in the spring season, just prior to the first root flush, to protect the new roots from nematode infection.
Three field trials was conducted in Ismailia governorate, Egypt during the seasons 2009, 2010 and 2011 to evaluate the efficacy of twelve granular and liquid chemical nematicides produced by different companies and three bio-nematicides on populations of root-knot nematodes, Meloidogyne javanica infesting banana and grape and citrus nematodes, Tylenchulus semipenetrans infesting orange as well as crop productivity. Among all chemical nematicides applied on banana, cure (oxamyl SL 24%) treatment at the rate of 15 ml/mat twice surpassed other treatments in reducing rate of nematode build-up with value of 0.24, followed by nemacur G 10% at 30 g/mat and vydate SL 24 % at 15 ml/mat twice treatments with the same value of 0.31 each, whereas nemathorin G 10 % treatment at 3 g/m 2 recorded the lowest reduction percentage of the same criterion with value of 0.50. Application of nemacur G 10% and vydate SL 24% gave the highest increment percentage in crop productivity with value of 65.6 % each, followed by cure treatment (59.2 %). Nemathorin treatment at 12.5 kg/feddan accomplished the best results in improving the production of orange fruits and reducing rate of T. semipenetrans build-up as well where the percentage increase value of productivity averaged to 91.8% and the reduction percentage value of nematode build-up averaged to 82.9%, but no significant differences were noticed among all nematicides tested. The highest reduction in rate of M. javanica build-up was obtained when grape trees treated with vydate 24% SL at the rate of 5 L/feddan twice that amounted to 0.29 as well as the highest percentage increase of crop production with value of 90.2%. It was clear that chemical nematicides gave more efficient control of nematode population density than the bio-nematicides for an immediate control on grape trees. Among all tested bio-nematicides, QL Agri 35 decreased rate of M. javanica build-up and increased grape production to the maximum with values averaged to (0.57 and 7.50).
2011
This study aimed to determine resistance level of some citrus cultivars to the citrus nematode (Tylenchulus semipenetrans Cobb). Number of T. semipenetrans female penetrated per cm root not significantly different on all citrus cultivar. Number T. semipenetrans female per cm root on all citrus cultivar was < 1 nematode per cm root. This fact showed that Citrus jambhiri, C. reticulate, C. aurantium, C. nobilis, C. medica, C. macrocarpa, and C. hystryx ABC showed resistant reaction on T. Semipenetrans.
A field treatment was conducted to evaluate the nematicidal activity of chicken manure and biopesticides (bio-arc , bio-zeid and nemex) viz. chemical nematicides (fydal 24 % SL , tervigo (2% SC), laguna (40% EC) and nemathorin (10% G) against plant -parasitic nematodes infecting fruit orchard located in Sharkia Governorate during 2018. Treatments of chicken manure was at the rate of 30 Kg/ tree , while that of biopesticides were applied at rate of 160 g/tree with bio-arc and bio-zeid , whereas nemex was applied at rate of 24 mL/ tree. Chemical nematicides were applied at rates of 15 mL//tree , 50 g/ tree , 24 mL/tree and 12 mL with fydal 24 % SL, tervigo , laguna and nemathorin , respectively. Samples were taken monthly during three months after application. Results indicated that of the eight tested materials, fydal was the most effective in suppressing umbers of phytonematodes followed by chicken manure while among biopesticides , bio-arc was the least effective one. After one month of application, remarkable decreased in numbers of plant-parasitic nematodes was detected. For instance, in fydal and chicken manure treatments, percentages of reduction in numbers of Tylenchulus semipenetrans, Pratylenchus spp., Tylenchorhynchus spp., Hoplolaimus spp. and Helicotylenchus spp. were diminished by 49.75 %(40.92 %) ,56.97% (53.54%), 55.47% (55.83%), 50.53% (50.53%) and 52.52 % (50.42%), respectively. After two months of application, percentage of reduction was increased to reach 69.25 %(68.53%) ,81.26% (71.37%), 83.18% (80.08%), 86.92% (83.00%) and 81.77 % (61.93%), respectively for mentioned nematodes. On the other hand, after three months of application, no significant differences ( P ≤ 0.05) was noticed between fydal and chicken manure whereas, the biopesticides were the least effectiveness against plant -parasitic nematodes. Generally, results emphasized that chicken and biopesticides could be used to minimize the population density of plant-parasitic nematodes in citrus orchards.
European Journal of Plant Pathology, 2003
Experiments simulating interplanting of resistant rootstocks with susceptible rootstocks that maintain high population densities of Tylenchulus semipenetrans in field soil were carried out in microplots at two locations, and in an naturally infested orchard. Selections of Cleopatra mandarin x Poncirus trifoliata (01) 03.01 .S and 03.01.13, Citrus volkameriarza (23) x P trifoliata 23.01.17, Troyer citrange (02) x Cleopatra mandarin 02.03.24, Troyer citrange x Common mandarin (04) 02.04.18, King mandarin x P. trifoliata 05.01.7, and Carrizo citrange were exposed to continuous high population densities of a population of the Mediterranean biotype of T. sernipenetrans. The selection 23.01.17 retained its resistance in the microplots and in the field (< 1.2% females and eggs per gran1 fibrous root of those on Carrizo citrange). The selection 03.01.5 also retained its resistance in the microplots at Moncada (<OS% females and eggs per gram fibrous root of those on Carrizo citrange) but numbers of females and eggs per gram fibrous root were 27% and 22% at Amposta, and 139% and 18% in the orchard of those on Carrizo citrange, respectively. The selection 05.0 1.7 supported equal number of females and 43% eggs per gram fibrous root of those on Carrizo citrange in the nematode-infested orchard. The remaining selections supported high populations of T. .retnipeiletrans.