scholarly journals First report of field bindweed (Convolvulus arvensis L.) penetrates the roots of pepper (Capsicum annuum L.) plants.

2018 ◽  
Vol 02 (04) ◽  
Author(s):  
F.M. Farag
Author(s):  
In-Sook Cho ◽  
Ju-Yeon Yoon ◽  
Eun-Young Yang ◽  
Soo-Young Chae ◽  
Bong Nam Chung ◽  
...  

Plant Disease ◽  
2009 ◽  
Vol 93 (8) ◽  
pp. 847-847 ◽  
Author(s):  
E. Kuleci ◽  
B. Tunali ◽  
D. K. Berner ◽  
C. A. Cavin ◽  
L. A. Castlebury

Field bindweed (Convolvulus arvensis L.; Convolvulaceae) is a troublesome perennial weed found among many important crops in the world (1). In May of 2007, dying field bindweed plants were found along the edge of a wheat (Triticum aestivum L.) field between Bafra and Taflan, Turkey (41°34.395′N, 35°52.215′E). Lesions on leaves were irregular and variable in size and dark black with green margins. Severely diseased leaves were wilted or dead. Fruiting bodies were not evident on field-collected material. Diseased tissue was surface disinfested and placed on moist filter paper in petri plates. Numerous pycnidia with alpha conidia were observed after 2 weeks. A fungus, designated 24-6, was isolated from the diseased leaves. Cultures on potato dextrose agar (PDA) were floccose with white mycelia and small black stromata. Alpha conidia from pycnidia on inoculated plants were biguttulate, one celled, hyaline, oblong to ellipsoid, and 7.0 to 12.8 × 3.0 to 5.5 μm (mean 10.0 × 3.9 μm). Neither beta conidia nor the teleomorph, Diaporthe sp., were observed on diseased tissue or in cultures. Morphology was consistent with that of Phomopsis convolvuli Ormeno-Nunez, Reeleder & A.K. Watson (2). Alpha conidia were harvested from 12-day-old cultures grown on PDA by brushing the surface of the colonies with a small paint brush, suspending the conidia in sterile distilled water, and filtering through cheesecloth. The conidia were then resuspended in sterile distilled water plus 0.1% polysorbate 20 to arrive at a concentration of 107 conidia/ml. Stems and leaves of seven plants at the 3- to 5-leaf stage were spray inoculated with 10 ml per plant of this aqueous suspension. Inoculated plants and two noninoculated plants were placed in a dew chamber at 24°C in darkness and continuous dew. After 48 h, plants from the dew chamber were moved to a greenhouse bench. Disease severity was evaluated 1 week after inoculation with a rating system based on a scale from 0 to 4, in which 0 = no symptoms, 1 = 1 to 25% necrosis, 2 = 26 to 50% necrosis, 3 = 51 to 75% necrosis, and 4 = 76 to 100% necrosis (2). The average disease rating on inoculated plants was 3.75. No disease was observed on noninoculated plants. P. convolvuli was reisolated from all inoculated plants. Comparison of the internal transcribed spacer (ITS) 1 and 2 sequences with available sequences of a vouchered P. convolvuli specimen (GenBank Nos. U11363, U11417; BPI 748009, FAU649) showed 192 of 193 and 176 of 179 identities, respectively, for the two regions. Nucleotide sequences for the ribosomal ITS regions (ITS 1 and 2, including 5.8S rDNA) were deposited in GenBank (Accession No. FJ710810), and a voucher specimen has been deposited with the U.S. National Fungus Collections (BPI 878927). To our knowledge, this is the second report in the world of leaf anthracnose on field bindweed caused by P. convolvuli. The first report was from Canada (3) of an isolate that was later patented for biological control of C. arvensis (4). References: (1) L. Holm et al. The World's Worst Weeds. University Press of Hawaii, Honolulu, 1977. (2) J. Ormeno-Nunez, et al. Can. J. Bot. 66:2228, 1988. (3) J. Ormeno-Nunez et al. Plant Dis. 72:338, 1988. (4) A. K. Watson et al. U.S. Patent 5,212,086, 1993.


Author(s):  
Juan Elías Sabino-López ◽  
P. García-Escamilla ◽  
M. Espinosa-Rodríguez ◽  
Y. Durán-Trujillo ◽  
O. Talavera-Mendoza ◽  
...  

Objectives: To generate information about a new host of the Polyphagotarsonemuslatus (Banks) mite, and to understand the damages caused by the cultivation ofApatlexco chili pepper (Capsicum annuum L.) in the northern region of the state ofGuerrero.Design/Methodology/Approach: The identification of the mite was carried out throughtaxonomic keys and the damages caused in vegetative shoots, mature leaves andflower buds were described.Results: The P. latus mite was identified as causing important damage to the crops ofAplaxtleco chili pepper grown in greenhouses in the state of Guerrero, Mexico, and thisis the first report of this mite in the Aplaxtleco chili pepper crop grown in greenhouses inthe state of Guerrero, Mexico.Findings/Conclusions: Economic income is obtained from the cultivation of Aplaxtlecochili peppers, a characteristic crop of the municipality of Aplaxtla, in the northern zone of Guerrero; therefore, knowing the identity of the P. latus mite in the Aplaxtleco chili cropwill help to suggest effective control methods to obtain higher yields.


2019 ◽  
Vol 86 (1) ◽  
pp. 76-79
Author(s):  
Yoshifumi Shimomoto ◽  
Kenichi Ikeda ◽  
Yasushi Asahina ◽  
Kazutaka Yano ◽  
Misako Oka ◽  
...  

2018 ◽  
Vol 7 (1) ◽  
pp. 51-51
Author(s):  
Sajjad Hyder ◽  
Muhammad Inam-ul-Haq ◽  
Raees Ahmed ◽  
Amjad S. Gondal ◽  
Nida Fatima ◽  
...  

Bell pepper (Capsicum annuum L.) is one of the extensively cultivated vegetable crop in Punjab, Pakistan. During two years of field surveys, February-November 2016-17, damping off and blight symptoms were observed. Average seedling mortality was recorded as 18.7% while yield loss due to blight was estimated 32 to 41% at mature stages. Maximum blight infection was recorded from the areas frequently flooded with canal irrigation system. At early stages, lesions were noticed on stem portions at soil line level while at crop maturity stages blight symptoms were noted. Leaves were blanched and wilted while fruits were covered with white mold. Masses of sporangia were evident on and inside the infected fruits under humid conditions. A total of twelve isolates were recovered from infected root, stem and fruit portions on rye agar media (Caten and Jinks, 1968) incubated at 25oC under fluorescent light. Papillated sporangia were averaged 42 ± 2.6 X 27 ± 1.7 μm in size (range 27 - 52 × 23 - 36 μm). Oospores were produced on 20% V8 agar and were spherical 22 ± 1.4 μm in diameter (range 14 to 27 μm) while average pedicels length was recorded as 58 ± 12.5 μm (range 13 to 120 μm). These observations were similar to those described for P. capsici (Cocoa, 1988). DNA was extracted using Cetyl Trimethylammonium Bromide (CTAB) method and the internal transcribed spacer regions (ITS1 and ITS2) were amplified by polymerase chain reaction (White et al., 1990). The amplicons were purified and sequenced in both directions (GenBank Accession No. MF322868 and MF322869). BLAST analysis revealed these isolates showed 99% identity with ITS sequences of Phytophthora capsici (KM369964 and KU518782). Pathogenicity assay was performed on healthy bell pepper seedlings with five repeats. Soil was flooded with 20ml sporangial suspension (1 x 103 sporangia/ml) in pots containing seedlings while 5ml suspension was sprayed until run off on mature plants (Hyder et al., 2018). A set of uninoculated seedlings was used as control. Pots were kept in dew chamber for 10-20 days at 25±2 oC. Seedling mortality was observed five days after inoculation while at later stage plants develop brown-to-black stem lesions with white mycelial growth on leaves. These symptoms were identical to the P. capsici infections in field. Consistent re-isolations of P. capsici confirm its association with the disease. To our knowledge, this is the first report of Phytophthora blight on bell pepper from Pakistan


2003 ◽  
Vol 4 (1) ◽  
pp. 31
Author(s):  
Dean A. Glawe ◽  
Gwenyth E. Windom ◽  
Gary G. Grove ◽  
Jennifer S. Falacy

Field bindweed (Convolvulus arvensis L.) is widespread in the Pacific Northwest where it is considered a noxious weed. During 2002, collections of a powdery mildew fungus attacking C. arvensis were made from Pierce, Spokane, Whitman, and Yakima counties, WA. Based on morphological features we determined the fungus to be Erysiphe convolvuli. Accepted for publication 22 September 2003. Published 21 October 2003.


Plant Disease ◽  
2021 ◽  
Author(s):  
Luqman Amrao ◽  
Muhammad Zeshan Ahmed ◽  
Saba Saeed ◽  
Rashida Atiq ◽  
Muhammad Subhan Shafique ◽  
...  

Chili (Capsicum annuum L.) is an important vegetable crop in Pakistan. During summer of 2019, chili leaf spot symptoms were observed on 3-month-old plants in the fields, with 30 to 40% of disease incidence, in District Faisalabad, Punjab, Pakistan. Diseased leaves were characterized by numerous tiny round spots (0.5 to 2.0 mm in diameter, average 1 mm) that were white to grey with a sunken center, surrounded with dark brown edge and chlorotic halo. The lesions gradually enlarged and coalesced into large, nearly circular, or irregularly shaped lesions that could be as long as 3 cm. Small pieces of symptomatic leaf tissues were surface sterilized in 1% sodium hypochlorite for 1 min, rinsed in sterile water, and plated on potato dextrose agar (PDA) amended with streptomycin (100 ppm). After 5 days at 25°C with a 12-hour photoperiod, same fungal colonies developed. The colonies initially appeared white and then turned olive-green. The conidiophores were brown septate and generally branched. Conidia borne singly or in short chains were multicellular, obclavate to obpyriform, and 16.2 to 38.5 µm (average 27.35 ± 2.1 µm) in length and 8 to 16.5 µm (average 12.25 ± 1.6 µm) in width, with zero to three longitudinal and two to five transverse septa (n=35). The fungus was identified as Alternaria sp. (Fr.) Keisel based on its morphological characteristics (Simmons et al. 2007). For molecular identification, genomic DNA of two representative isolates (SSUAF1 and SSUAF2) was extracted using DNAzol reagent and PCR amplification of the internal transcribed spacer (ITS)-rDNA region, Glyceraldehyde 3-phosphate dehydrogenase gene (GAPDH) gene and RNA polymerase II second largest subunit (rpb2) were performed with primers ITS1/ITS4 (White et al. 1990), gpd1 and gpd2 (Berbee et al. 1999), RPB2-5F/RPB2-7cR (Liu, et al. 1999), respectively. The obtained sequences were deposited in GenBank with acc. nos. MT249008.1 and MT249009.1 for ITS-rDNA; MT318220.1 and MT318221.1 for the GAPDH; and MT318236.1, and MT318237.1 for RPB2 gene. A BLAST search in GenBank showed 100% identity with A. alternata for both ITS region (MT279999.1), GAPDH gene (MK637438.1) and RBP2 gene (MK605900.1). To confirm pathogenicity, 2-month-old healthy potted C. annuum plants were inoculated using an atomizer in a greenhouse. A total of 12 plants at the true leaf stage in each experiment were sprayed with a conidial suspension (106 conidia/ml) of both isolates amended with 0.1% (vol/vol) of Tween 20 until runoff (1.5 to 2 ml per plant). Four plants were inoculated with each of the two isolates, whereas four control plants were sprayed with sterile distilled water amended with 0.1% Tween 20. The plants were incubated at 25 ± 2°C in a greenhouse. After 10 days of inoculation, each isolate induced leaf lesions that were similar to typical lesions observed in the field. The experiment was conducted twice with similar results. The fungus was readily reisolated from symptomatic tissues whereas the control plants remained symptomless. Re-isolated fungal cultures were morphologically and molecularly identical to A. alternata, thus fulfilling the Koch’s postulates. Previously, A. alternata has been reported in Italy and India (Devappa et al. 2016; Garibaldi et al. 2019). To our knowledge, this is the first report of A. alternata causing leaf spot of C. annuum in Pakistan. This report will help the identification of leaf spot of chili and the development of management strategies for control of this disease in Pakistan.


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