Pathogenicity and reproductive fitness of Pratylenchus brachyurus on cowpea

Nematology ◽  
2008 ◽  
Vol 10 (4) ◽  
pp. 495-500 ◽  
Author(s):  
Kércya Maria Simões de Siqueira ◽  
Mário Massayuki Inomoto

AbstractThe lesion nematode Pratylenchus brachyurus is widespread in cowpea plantations throughout the tropics and sub-tropics. However, the pathogenicity of P. brachyurus on cowpea has been scarcely studied. In this work, it was demonstrated in two glasshouse experiments that an isolate (Pb20) of P. brachyurus was pathogenic to cowpea cv. IPA-206, adversely affecting the plant growth and pod formation and filling. Initial population levels of 5000 and 15 000 nematodes per plant caused reduction of root growth and typical decay of root tissue. The third experiment demonstrated that all six cowpea cultivars selected for evaluation supported reproduction of three isolates of P. brachyurus (Pb20, Pb21 and Pb23) in their roots, although the reproduction factor values obtained indicated that they were dissimilar in their reproductive fitness. Low resistance to P. brachyurus was reported for at least one tested cultivar, but apparently of an insufficient degree to be effective for field management of the nematode.

Nematology ◽  
2020 ◽  
pp. 1-8
Author(s):  
Paulo V.M. Pacheco ◽  
Thalita S.A. Monteiro ◽  
Raul R. Coutinho ◽  
Huarlen M. Balbino ◽  
Leandro G. de Freitas

Summary Pratylenchus brachyurus is considered one of the most important plant pathogens of soybean and corn in Brazil, mainly found in areas where no-tillage is practised. Nematophagous fungi are used as an alternative for chemical nematicides in the management of nematodes that affect these crops in Brazil. This study evaluated the fungi Pochonia chlamydosporia, Trichoderma sp. and Duddingtonia flagrans for the biocontrol of P. brachyurus in soybean and corn. The first and second experiments were carried out using soybean, and five isolates of P. chlamydosporia (Pc-3, Pc-4, Pc-10, Pc-35 and Pc-49), one of Trichoderma sp. (T-10), an isolate of D. flagrans (AC001) and a mix (MIX) of all the isolates. In the third experiment using corn, three isolates of P. chlamydosporia (Pc-3, Pc-10 and Pc-35) and one isolate of Trichoderma sp. (T-10) were compared. In the first experiment, the isolates Pc-3, Pc-10, Pc-35 and T-10 reduced the total population of P. brachyurus up to 43.7% when compared with the control treatment. In the second experiment, the isolates Pc-10, T-10 and the MIX reduced the total population of P. brachyurus up to 58.7% when compared with the control. In the third experiment, the isolates reduced the total population of P. brachyurus in corn when compared with the control treatment, except for D. flagrans, which was not able to control P. brachyurus in any experiment. The P. chlamydosporia (Pc-3, Pc-10, Pc-35) and Trichoderma sp. (T-10) isolates were shown to be promising for the control of P. brachyurus in soybean and corn.


2017 ◽  
Vol 35 (0) ◽  
Author(s):  
C. BELLÉ ◽  
T.E. KASPARY ◽  
P.R. KUHN ◽  
J. SCHMITT ◽  
I. LIMA-MEDINA

ABSTRACT Weeds can be hosts of root-lesion nematode (Pratylenchus spp.), maintaining or increasing their population in the soil. The objective of this study was to evaluate the reaction of 25 weeds species to the nematode Pratylenchus zeae. The weed plants were individually inoculated with 1,000 individuals of P. zeae and maintained in a greenhouse for 90 days. After this period, eggs and nematodes were extracted, quantified, and the reproduction factor (RF = final population/initial population) was calculated. All tested weeds were susceptible (RF>1) to P. zeae, and the species Brachiaria decumbens, Rhynchelytrum repens, Digitaria insularis, D. horizontalis, B. brizantha were the most susceptible to this parasite.


2018 ◽  
Vol 44 (2) ◽  
pp. 143-147
Author(s):  
Lais Fernanda Fontana ◽  
Claudia Regina Dias Arieira ◽  
Vinicius Hicaro Frederico Abe ◽  
José Junior Severino ◽  
Jailson de Oliveira Arieira ◽  
...  

ABSTRACT Root-knot nematodes, Meloidogyne spp., and the root-lesion nematode, Pratylenchus brachyurus, are the most common phytoparasites in soybean crop, which usually occur in association in crop areas. However, few studies were conducted on the interaction between these parasites. Therefore, this study aimed to assess the interference of the increase in M. javanica population in the reproduction of P. brachyurus, and the effect of mixed populations on soybean (cultivar BRS/MT Pintado) development. The experiment consisted in inoculating a population of 1000 specimens of P. brachyurus per plant and changing the inoculum level of M. javanica, using zero, 1000, 2000 and 4000 eggs, in two different periods. After 65 days of inoculation, the increase in the initial population of M. javanica reduced by 79 and 73% the final population of P. brachyurus in the different experiments. However, both species significantly increased their populations. When subjected to the same inoculum level, M. javanica was more efficient in reproducing than P. brachyurus. The increase in the number of nematodes reduced the vegetative growth of the plant.


2004 ◽  
Vol 18 (3) ◽  
pp. 605-610 ◽  
Author(s):  
Diego J. Bentivegna ◽  
Osvaldo A. Fernández ◽  
María A. Burgos

Chemical weed control with acrolein has been shown to be a lower cost method for reducing submerged plant biomass of sago pondweed in the irrigation district of the Lower Valley of Rio Colorado, Argentina (39°10′S–62°05′W). However, no experimental data exist on the effects of the herbicide on plant growth and its survival structures. Field experiments were conducted during 3 yr to evaluate the effect of acrolein on growth and biomass of sago pondweed and on the source of underground propagules (i.e., rhizomes, tubers, and seeds). Plant biomass samples were collected in irrigation channels before and after several herbicide treatments. The underground propagule bank was evaluated at the end of the third year. Within each treatment, plant biomass was significantly reduced by 40 to 60% in all three study years. Rapid new plant growth occurred after each application; however, it was less vigorous after repeated treatments. At the end of the third year at 3,000 m downstream from the application point, plant biomass at both channels ranged from 34 to 3% of control values. Individual plant weight and height were affected by acrolein treatments, flowering was poor, and seeds did not reach maturity. After 3 yr, acrolein did not reduce the number of tubers. However, they were significantly smaller and lighter. Rhizomes fresh weight decreased by 92%, and seed numbers decreased by 79%. After 3 yr of applications, operational functioning of the channels could be maintained with fewer treatments and lower concentrations of acrolein.


2003 ◽  
Vol 81 (2) ◽  
pp. 152-163 ◽  
Author(s):  
Humberto Fabio Causin ◽  
Renata D Wulff

Morphological shade-avoidance responses have been hypothesized to be a form of adaptive plasticity to improve competition for light; however, little is known about their intraspecific variability and their effect on reproductive fitness. To compare plant responses either at a common age or at a common phenological stage, two experiments were conducted with early- and late-flowering Chenopodium album plants exposed to different red (660 nm) to far red (730 nm) ratios. In the first experiment, plant height and number of leaves were recorded at several times during the vegetative stage, and at the onset of flowering, each plant was harvested and other growth traits were measured. In the second experiment, three destructive harvests were performed across the whole plant cycle. Plant growth and development markedly differed between early- and late-flowering plants in all of the conditions tested. Light treatments significantly affected stem length, total leaf number, total leaf area, and relative allocation to leaf biomass. In all families, the response of stem elongation to light treatments decreased later in the development, while changes in the other plastic responses were mostly due to variations in plant growth. No significant treatment effect was found on relative biomass allocation to reproductive structures. However, individual seed mass significantly differed between certain groups, indicating that light quality can affect reproductive fitness through changes in traits other than fruit or seed set.Key words: Chenopodium album, fitness, intraspecific variability, phenotypic plasticity, red to far red ratio, shade-avoidance responses.


2020 ◽  
Vol 50 (7) ◽  
Author(s):  
Thays Torquato Cruz ◽  
Guilherme Lafourcarde Asmus ◽  
Rodrigo Arroyo Garcia

ABSTRACT: Soybean is the main agricultural crop in the State of Mato Grosso do Sul, Brazil. It is primarily cultivated in a crop succession system, in wich soybean is grown in spring/summer, followed by corn or graminaceous pastures in autumn/winter as a second crop. Due to the intensive cultivation, new phytosanitary problems have arisen, among them the root-lesion nematode, Pratylenchus brachyurus, which besides causing damage to plant roots, can be important gateway for other soil pathogens. The recent occurrence of high nematode population densities has brought great concern due to the limited resistant soybean genotypes available. Besides, the use of nematicides only reduces nematodes populations temporarily. A viable alternative for the control of soil nematodes could be the use of Crotalaria spp. in succession or rotation with soybean. Crotalaria is immune or a bad host to the nematode, besides having high capacity of biological nitrogen fixation. Thus, the objective of the present research was to define the best way of insertion of this legume as a second crop in soybean production systems to reduce the population density of the root-lesion nematode. Two experiments were carried out: one in the field, in an infested area, and other in a greenhouse. In both experiments, the treatments were: 1) Zea mays, 2) Brachiaria brizantha cv. Xaraés,, 3) Z. mays + Crotalaria spectabilis, 4) Z. mays + C. ochroleuca, 5) B. brizantha cv. Xaraés + C. spectabilis, 6) B. brizantha cv. Xaraés + C. ochroleuca, 7) C. spectabilis, and 8) C. ochroleuca. The effect of the treatments was evaluated by estimating the number of nematodes in the roots of autumn/winter crops, as well as in the roots of the soybean cultivated in the sequence. The cultivation of both Crotalaria species provided suppression of the nematode population. However, when intercropped with corn or Xaraés palisade grass, the suppressive effect of Crotalaria was supplanted by corn and Xaraés palisadegrass susceptibility to the root-lesion nematode.


EUGENIA ◽  
2012 ◽  
Vol 21 (3) ◽  
Author(s):  
Stanley A.F. Walingkas ◽  
Meity Rantung

ABSTRACT This study aims to determine the effect of plant growth regulators and micro elements to cherelle wilt in cacao plants as well as finding the right business in tackling cherelle wilt in cacao plants. The research was carried out in the garden village folk Eris Eris Minahasa district for 8 months from January to August 2009. Spraying micro-nutrient elements is necessary to reduce cherelle wilt because the various treatments for the first observation is not significantly different, but the observations into two to seven observations to indicate a significant difference between treatments (percentage cherelle wilt on treatment without nutrient elements higher than sprayed). While spraying the treatment factor of plant growth regulators (NAA) is not necessary because the first observation and the two had no significant effect on the percentage of cherelle wilt affected only the third observation and further observations to a fourth, fifth, sixth and seventh again no effect. So is the treatment for fruit length and diameter showed that administration of the micro nutrients necessary for sprayed with micro nutrients result 22.10 cm higher than that is not sprayed is 19.43 cm. As for the diameter of the fruit is affected by plant growth regulators. Treatment is better than 200 ppm 100 ppm and 0 ppm (control). Keywords: NAA, cocoa, mikombi     ABSTRAK   Penelitian ini bertujuan mengetahui pengaruh pemberian zat pengatur tumbuh dan unsur mikro terhadap cherelle wilt pada tanaman kakao serta menemukan usaha yang tepat dalam menanggulangi cherelle wilt pada tanaman kakao. Penelitian ini dilaksanakan di kebun rakyat Desa Eris Kecamatan Eris Kabupaten Minahasa selama 8 bulan sejak Januari – Agustus 2009. Penyemprotan unsur hara mikro perlu dilakukan untuk mengurangi cherelle wilt sebab pada berbagai perlakuan untuk pengamatan pertama tidak berbeda nyata namun pada pengamatan ke dua sampai pengamatan ke tujuh menunjukkan adanya perbedaan nyata antar perlakuan (prosentase cherelle wilt pada perlakuan tanpa unsure hara lebih tinggi dari yang disemprot). Sementara faktor penyemprotan dengan perlakuan zat pengatur tumbuh (NAA) tidak perlu dilakukan sebab pengamatan pertama dan ke dua tidak berpengaruh nyata pada persentase cherelle wilt hanya berpengaruh pada pengamatan ke tiga dan selanjutnya pengamatan ke empat, ke lima, ke enam dan ke tujuh kembali tidak berpengaruh. Begitu juga perlakuan untuk panjang dan diameter buah menunjukkan bahwa pemberian unsur hara mikro perlu dilakukan sebab yang disemprot dengan unsur hara mikro hasilnya 22,10 cm lebih tinggi dari yang tidak disemprot yaitu 19,43 cm. Sementara untuk diameter buah dipengaruhi oleh zat pengatur tumbuh. Perlakuan 200 ppm lebih baik dari 100 ppm dan 0 ppm (kontrol). Eugenia Volume 18 No. 2  Agustus 2012 Kata kunci : NAA, kakao, mikombi


O Biológico ◽  
2020 ◽  
Vol 82 (1) ◽  
pp. 1-10
Author(s):  
Samara A. de Oliveira ◽  
Juliana M. O Rosa ◽  
Juliana Eulálio ◽  
Claudio Marcelo G. de Oliveira

The aim of this study was to investigate the response of three different stages (one, three and five leaf pairs) of sweet pepper (Capsicum annuum cv. Orazio) seedlings to five inoculation levels of Meloidogyne enterolobii (zero (control), 300, 1000, 3000 and 10000) under greenhouse conditions. Each plant was cultivated in one pot filled with 3.8 L of substrate. The test was a completely randomized design with four replications. The plants were assessed 60 days after inoculation, plant shoot weight, final population of nematodes, and reproduction factor were measured. The results were fitted to Seinhorst model: Y = m + (1-m). ZPi –T. The results showed a tolerance limit (T) of 2,500 nematodes for plants with one and three leaf pair, and 8,500 nematodes for the five-leaf pair plant.


2017 ◽  
Vol 30 (2) ◽  
pp. 536-540 ◽  
Author(s):  
JAQUELINE TAVARES SCHAFER ◽  
CESAR BAUER GOMES ◽  
ARIONE DA SILVA PEREIRA ◽  
FERNANDA FERREIRA CRUZ ◽  
DANIELLE RIBEIRO DE BARROS

ABSTRACT The objective of this study was to evaluate the resistance of a group of clones and cultivars from the potato breeding program of Embrapa to Meloidogyne javanica. The experiment was conducted at Embrapa Temperate Climate, Pelotas / RS, under greenhouse conditions at temperatures of 25 ± 5°C. Individual potato plants of different genotypes [BRSIPR Bel, BRS F63 (Camila), CL02-05, F23-11-06, F32-02-06, F38-03-07, F189-09-06, F23-24-06 and F22-01-08], kept in pots with sterilized soil were inoculated with 5,000 eggs and J2 of M. javanica, using six replicates per treatment. The susceptible control, potato cultivar BRS Ana was inoculated with the same level of inoculum. Fifty-five days after inoculation, the number of galls on the roots of each plant was determined as well as the number of protuberances caused by nematodes in the different treatments. Then, the roots of each plant were processed for counting the number of eggs and J2, as well as determining the nematode reproduction factor (FR: final population / initial population). All genotypes were susceptible (FR> 1.00) to M. javanica. However, there were different levels of susceptibility among the cultivars tested.


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