scholarly journals First Report of Root Rot and Crown Necrosis Caused by Pythium aphanidermatum on Phaseolus vulgaris in Oman

Plant Disease ◽  
2015 ◽  
Vol 99 (3) ◽  
pp. 419-419 ◽  
Author(s):  
I. H. Al-Mahmooli ◽  
A. R. Al-Fahdi ◽  
A. M. Al-Sadi ◽  
M. L. Deadman

In March 2013, 90% of mature bean plants (Phaseolus vulgaris L. cv. Kendo) grown on a commercial farm in the north of Oman (Barka) developed symptoms of root rot and necrotic streaks on the crown area of the stem and wilted. A Pythium spp. was isolated consistently from roots and basal stems on 2.5% potato dextrose agar (PDA) and V8 (100% vegetable juice) plus 1.5% agar technical. Colonies of Pythium spp. on PDA and V8 plus agar developed abundant aerial mycelia, with the main hyphae being up to 10 μm wide. Zoosporangia were made up of terminal complexes of swollen hyphal branches of different lengths and up to 22 μm wide. Oogonia were terminal, globose, and smooth with a 26-μm diameter (average of 20). Antheridia were mostly intercalary, sometimes terminal, and broadly sac-shaped, 15 μm long and 11 μm wide (average of 20). Oospores were aplerotic, 23 μm in diameter (average of 24), with walls 1 to 2 μm thick at 25°C (ambient temperature). The internal transcribed spacer of the ribosomal DNA (ITS1 and ITS4) sequence of the isolates matched the sequence of Pythium aphanidermatum (Edson) Fitzp. in GenBank. The sequence of isolate Py1 was deposited in GenBank as Accession No. KM102739. This isolate was identified as P. aphanidermatum on the basis of morphological and cultural characteristics (1) and the ITS rDNA sequence. The ITS was found to share 100% nucleotide similarity to previously published sequences of the ITS (KJ755088). To fulfill Koch's postulate, a 5-mm plug of 5-day-old mycelium of isolate Py1 grown on 2.5% PDA was used to inoculate healthy seedlings of beans cv. Kendo. The plug was placed adjacent to the bean stem; PDA served as a control. Five replicate plants were used for the treatment and the control. The plants were maintained in a glasshouse at a temperature of 23 to 25°C. The plants were watered every day. The irrigation water had an electrical conductivity value of 0.2 dSm−1. Eleven days after inoculation, 90% of the plants developed root rot, crown necrosis, and wilt symptoms similar to those observed in the field. On the other hand, control plants did not show any symptoms. The pathogen was re-isolated from roots and basal stems of symptomatic plants. To our knowledge, this is the first report of P. aphanidermatum as the causal agent of root and crown necrosis of mature bean plants in Oman. Future studies should focus on evaluating management options for this disease to avoid possible losses in a crop that has a high export value in Oman. Reference: (1) Y. Serrano et al. Plant Dis. 92:174, 2008.

Plant Disease ◽  
2018 ◽  
Vol 102 (12) ◽  
pp. 2639-2639 ◽  
Author(s):  
H. Sang ◽  
J. L. Jacobs ◽  
J. Wang ◽  
C. M. Mukankusi ◽  
M. I. Chilvers

1973 ◽  
Vol 15 (2) ◽  
pp. 123-125
Author(s):  
V. K. Gupta ◽  
G. S. Saharan

2019 ◽  
Vol 20 (9) ◽  
pp. 2327 ◽  
Author(s):  
Marcello Iriti ◽  
Alessio Scarafoni ◽  
Simon Pierce ◽  
Giulia Castorina ◽  
Sara Vitalini

EM (effective microorganisms) is a biofertilizer consisting of a mixed culture of potentially beneficial microorganisms. In this study, we investigated the effects of EM treatment on leaf in vivo chlorophyll a fluorescence of photosystem II (PSII), yield, and macronutrient content of bean plants grown on different substrates (nutrient rich substrate vs. nutrient poor sandy soil) in controlled environmental conditions (pot experiment in greenhouse). EM-treated plants maintained optimum leaf photosynthetic efficiency two weeks longer than the control plants, and increased yield independent of substrate. The levels of seed nutritionally-relevant molecules (proteins, lipids, and starch) were only slightly modified, apart from the protein content, which increased in plants grown in sandy soil. Although EM can be considered a promising and environmentally friendly technology for sustainable agriculture, more studies are needed to elucidate the mechanism(s) of action of EM, as well as its efficacy under open field conditions.


Plant Disease ◽  
2017 ◽  
Vol 101 (6) ◽  
pp. 1038 ◽  
Author(s):  
J. Beckerman ◽  
H. Nisonson ◽  
N. Albright ◽  
T. Creswell

2014 ◽  
Vol 10 (2) ◽  
pp. 283-293
Author(s):  
Barbara Łacicowa ◽  
Zofia Machowicz

The results obtained in pot and field experiments have shown that <i>Helminthosporium sorokinianum</i> is able to infect bean plants. The cotyledons and roots of shoots during the first three weeks of growth are attacked the most frequently. Dark brown spots occur on the above-mentined organs. The infection of roots and cotyledonsof shoots is responsible for gangrene both before and after germination. Infected plants which remain alive only show symptoms of infection in the root system. The infection of roots by <i>H. sorokinianum</i> in older plants is detromental to growth and causes a decrease in the vield obtained from bean plants.


1950 ◽  
Vol 1 (2) ◽  
pp. 148 ◽  
Author(s):  
CG Greenham

As determined by the length for which roots were killed, there was no diurnal variation in the effectiveness on skeleton weed (Chondrilla juncea L.) of spray applications of 'Methoxone' at two-hourly intervals over a period of 24 hours. As determined by reduction in growth above the primary leaves, there was a well-marked diurnal variation in the effectiveness on bean plants (Phaseolus vulgaris L.) of drop applications of 'Methoxone.'


2017 ◽  
Vol 60 (6) ◽  
pp. 1983-1994 ◽  
Author(s):  
Mónica Espadafor ◽  
Lairson Couto ◽  
Morethson Resende ◽  
Delbert W. Henderson ◽  
Margarita García-Vila ◽  
...  

Abstract. AquaCrop is a crop simulation model developed by the FAO aimed at assessing the yield response to water supply. Once the model is calibrated and validated, it is a useful tool to simulate crop yields under different management options or climatic and soil conditions. Until now, AquaCrop has not been parameterized for dry beans ( L.), and thus our objective was to calibrate and validate the model for this crop using experiments performed 40 years ago at Davis, California. A set of parameters derived from the calibration with one irrigation experiment was used to validate the model using five experiments carried out in 1977 and 1978 that had treatments vastly differing in irrigation depth and frequency. Yield predictions over a wide range of values (&lt;1 to 3.5 t ha-1) were very good, with RMSE of 0.16 t ha-1 and Willmott’s d of 0.978. Seasonal ET was also accurately predicted by the model (RMSE = 40 mm, d = 0.930), as also evidenced by comparing the lysimeter measured ET of 489 mm against the lysimeter simulated ET of 501 mm. Canopy cover and the time course of biomass were adequately simulated as well. Even though total soil water extraction was well simulated, the simulated soil water distribution with depth differed from measured values in the dryland treatment. We conclude that AquaCrop can now be used for the simulation of dry beans in different environments, and we emphasize the value of carefully conducted field experiments for the validation of crop simulation models. Keywords: AquaCrop, Calibration and validation, Dry beans (Phaseolus vulgaris L.), Irrigation, Simulation model, Water stress.


2008 ◽  
Vol 51 (5) ◽  
pp. 883-888 ◽  
Author(s):  
Maria Celeste Gonçalves-Vidigal ◽  
Claudia Thomazella ◽  
Pedro Soares Vidigal Filho ◽  
Marcus Vinícius Kvitschal ◽  
Haroldo Tavares Elias

In 2003 and 2004, 32 isolates of Colletotrichum lindemuthianum obtained from the infected plants of field-grown common bean (Phaseolus vulgaris L.) in Santa Catarina state, Brazil were analyzed based on the virulence to 12 differential cultivars of Phaseolus vulgaris L.. Thirteen distinct races were identified, six of which had not been reported previously in Santa Catarina. This is the first report of the occurrence of 67, 83,101,103,105, and 581 races of C. lindemuthianum. Race 65 was most common (34%). All the isolates were compatible to the cultivars Michelite and Mexico 222. Some isolates infected not only differential cultivar of Mesoamerican origin, but also the ones of Andean origin.


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