Fruit rot of sweet pepper caused by <Emphasis Type="Italic">Stemphylium lycopersici</Emphasis> in Japan

A severe rot of postharvest fruits of sweet pepper, a variety of Capsicum annuum, was found in Kagawa Prefecture in southwestern Japan in August 1999. A fungus, isolated repeatedly from the diseased fruits and identified as Stemphylium lycopersici, was demonstrated to be pathogenic to fruits of sweet pepper. The disease was new to Japan, and the fungus was added to the pathogens causing fruit rot of C. annuum.     

Corynespora blight of sweet pepper (<Emphasis Type="Italic">Capsicum annuum</Emphasis>) caused by <Emphasis Type="Italic">Corynespora cassiicola</Emphasis> (Berk. &; Curt.) Wei

In 2004, Corynesopra cassiicola was isolated from dark brown spots on leaves and fruits and from black blights on stems of sweet pepper plants in Kochi Prefecture, Japan. The isolated fungus was then used to inoculate sweet pepper plants and subsequently reisolated from the plants with dark brown spots and black blights, showing that C. cassiicola is a new pathogen causing Corynespora blight on sweet pepper plants. The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases as accession numbers AB366649 (TS-C11), AB366650 (TS-C21), AB366651 (TI-C32) and AB366652 (TI-C51)     

Internal fruit rot of sweet pepper caused by Fusarium lactis in Japan and fungal pathogenicity on tomato and eggplant fruits

Journal of General Plant Pathology - A postharvest rot of ripe sweet pepper fruits was found in Kagawa Prefecture in western Japan in October 2002. A fungus, isolated repeatedly from the diseased...     

Avoiding Secondary Leaf Fall Disease of Rubber by Chemical Defoliation

Abstract

An intensive survey of cultivated plants throughout the island of Montserrat resulted in the identification of a number of viruses. Squash mosaic virus was found in cantaloupe, pumpkin and squash. There were cases of multiple infection of pumpkin and squash by cucumber and squash mosaic viruses. Potato virus Y was recovered from pepper and tomato. Bean yellow mosaic and cowpea mosaic viruses were found in red kidney bean and string bean while cowpea mosaic virus was found in cowpea and broad bean (Jamaica bean). Other viruses that were previously identified on the basis of field symptomatology were confirmed by host range and serology. Viruses were not recovered from sea island cotton or from sweet potato, although field symptoms on the sweet potato are similar to those caused by sweet potato mosaic virus. The leaf tissues of crop plants were inoculated to a wide range of indicator plants. Some of those that reacted systemically were examined by electron microscopy for virus particles and the sap extracted from them was used in serodiagnostic assays for virus identification. This is the first attempt to identify positively the viruses of crop plants on the island.     

Incidence and pathogenicity of races and isolates of Verticillium dahliae in Crete, southern Greece

Classification of 32 Verticillium dahliae isolates originating from 19 plant species in eight different botanical families to races and determination of host range pathogenicity were carried out. The physiological races of isolates were identified using the two differential tomato cultivars ??Belladonna?? (susceptible to both races 1 and 2 of V. dahliae) and ??Ace 55VF?? (resistant to race 1, susceptible to race 2 of V. dahliae). Among these isolates, 14 were race 2 (43.8%), 12 race 1 (37.5%) and six nonpathogenic (18.7%) on tomato. The host range pathogenicity of isolates was determined using four differential hosts (eggplant, turnip, tomato (Ve ^? ) and sweet pepper). Among isolates, five were pathogenic to both eggplant and turnip (15.6%), 21 to eggplant, turnip and tomato (65.6%), five to eggplant, turnip, tomato and sweet pepper (15.6%) and one was pathogenic to eggplant, turnip and sweet pepper (3.2%). The pathogenicity of isolates on the aforementioned five hosts was investigated on the basis of external symptoms and by calculating the relative areas under disease progress curves (relative AUDPC). Results showed that eggplant was the most susceptible, followed by turnip and tomato cv. Belladonna, while sweet pepper and tomato cv. Ace 55VF were less susceptible to all the isolates used. The pathogenicity of isolates varied from highly to mildly virulent on eggplant and turnip while on Belladonna, Ace 55VF and sweet pepper it varied from highly virulent to nonpathogenic. Belladonna exhibited a similar level of susceptibility to races 1 and 2 of V. dahliae, but was more susceptible than Ace 55VF to race 2. Interestingly, the isolates originating from eggplant were clearly more virulent than those originating from tomato and black nightshade on all solanaceous plants tested.     

间作对甜玉米田主要害虫与天敌动态的影响

为明确甜玉米间作不同作物对害虫的控制作用,采用目测法系统调查了甜玉米单作、甜玉米与绿豆、菜豆、甘薯或花生间作生境玉米主要害虫和天敌种群发生动态,并比较了不同生境亚洲玉米螟的为害情况。间作生境中捕食性天敌蜘蛛和瓢虫类群的个体数量均明显增加,其中甜玉米间作绿豆或甘薯生境蜘蛛类群增长21%以上,瓢虫类群增长83%以上,显著高于甜玉米单作生境;不同生境间玉米螟赤眼蜂发生量差异不显著,对亚洲玉米螟卵的寄生率均达到86%以上。间作生境玉米生育期内亚洲玉米螟落卵量、斜纹夜蛾及玉米蚜发生量均与甜玉米单作无显著差异,但收获期甜玉米间作生境玉米螟为害率低于单作生境,其中以甜玉米间作绿豆生境最低,总蛀孔数和活虫数分别比单作生境下降55.72%和76.70%。表明间作不同作物对甜玉米田具有一定的控害增益作用。     

Bicarbonate solutions control powdery mildew (Leveillula taurica) on sweet red pepper and reduce the development of postharvest fruit rotting

Disease severity of powdery mildew (causal agentLeveillula taurica (Lév.) Arn.) on pepper (Capsicum annuum), defoliation and fruit sunscald rating were significantly reduced (P=0.05) by foliar applications of sodium or potassium bicarbonate solutions, compared with water or penconazole (Ophir). Preharvest application of bicarbonate solutions significantly reduced (P=0.05) postharvest decay development on sweet red pepper fruits.     

Serratia marcescens associated with bell pepper (Capsicum annuum L.) soft-rot disease under greenhouse conditions

Soft-rotting bacteria affecting bell peppers crops represent an economically destructive disease of growing importance worldwide. In Venezuela since 2006, soft-rot symptoms have been occasionally observed in bell pepper fruits grown under greenhouse conditions. Affected fruits presented water-soaked lesions that progressed to complete fruit maceration. Bacteria were isolated from water-soaked lesions in order to identify the causal agent of this disease. Of 13 bacterial isolates recovered from affected fruits, only isolate AGPim1A was able to produce a hypersensitive reaction in tobacco plants and to reproduce soft-rot symptoms in bell peppers fruits. Several methods, including classical bacteriological tests and carbon utilization profiling, alongside with sequence analysis of 16S rRNA and housekeeping genes gyrB and groES-groEL, allowed identification of the soft-rotting bacterium as Serratia marcescens. To our knowledge, this is the first report showing a S. marcescens strain associated with soft-rot disease in bell pepper fruits.     

Differential reaction of sweet pepper to infection with the crinivirus tomato chlorosis virus probably depends on the viral variant

The tomato chlorosis virus (ToCV), transmitted by whitefly species of the genera Bemisia and Trialeurodes in a semipersistent manner, causes significant losses in solanaceous crops including tomato (Solanum lycopersicum) and sweet pepper (Capsicum annuum). Worldwide reports of natural and experimental infection of sweet pepper plants with ToCV are contradictory, raising the question of whether the critical factor determining infection is related to the susceptibility of sweet pepper cultivars or the genetics of virus isolates. In this work, ToCV isolates obtained from different hosts and geographical origins were biologically and molecularly analysed, transmitted by B. tabaci MEAM1 and MED, and the reaction of different sweet pepper cultivars was evaluated under different environmental conditions. Brazilian ToCV isolates from tomato, potato (S. tuberosum), S. americanum, and Physalis angulata did not infect plants of five sweet pepper cultivars when transmitted by B. tabaci MEAM1. Temperatures did not affect the sweet pepper susceptibility to tomato-ToCV isolates from São Paulo, Brazil, and Florida, USA. However, sweet pepper-ToCV isolates from Spain and São Paulo, Brazil, were transmitted efficiently to sweet pepper plants by B. tabaci MEAM1 and MED. Although the results indicated that ToCV isolates from naturally infected sweet pepper plants seem to be better adapted to plants of C. annuum, phylogenetic analyses based on the complete nucleotide sequences of RNA1 and RNA2 as well as the p22 gene did not reveal significant nucleotide differences among them. Additional studies are needed to identify intrinsic characteristics of ToCV isolates that favour infection of sweet pepper plants.     

Pathogenicity of Colletotrichum gloeosporioides to carrot

Abstract

Colletotrichum gloeosporioides was identified as the causal agent of carrot umbel blight in Brazil. Pathogenicity was evaluated on carrot and other host plants, as well as compared with the pathogenicity of other C. gloeosporioides isolates on carrot. C. gloeosporioides isolated from carrot umbel was able to infect tomato plants and ripe fruits of tomato and sweet pepper, in addition to carrot umbels and seedlings. This appears to be the first report of C. gloeosporioides attacking carrots.     

Endophytes of <Emphasis Type="Italic">Lippia citriodora</Emphasis> (Syn. <Emphasis Type="Italic">Aloysia triphylla</Emphasis>) enhance its growth and antioxidant activity

Sweet pepper (Capsicum annuum) is a popular crop worldwide and an asymptomatic host of the begomovirus (Geminiviridae) Tomato yellow leaf curl virus (TYLCV). A previous study showed that TYLCV could be transmitted by the seeds of tomato plants, but this phenomenon has not been confirmed in other plants. In 2015, four different cultivars of sweet pepper (‘Super Yellow,’ ‘Super Red,’ ‘Sunnyez’ and ‘Cupra’) known to be susceptible to TYLCV were agro-inoculated with a TYLCV infectious clone. Three months after inoculation, the leaves of the ‘Super Yellow’ cultivar showed 80% (8/10) susceptibility and the other three sweet pepper cultivars showed 30 to 50% susceptibilities. All of the ‘Super Yellow’ seed bunches (five seeds per bunch) from plants whose leaves were confirmed to be TYLCV-infected were also TYLCV-infected (8/8). The seeds of other cultivars showed 20 to 40% susceptibilities. Virus transmission rates were also verified with 10 bunches of seedlings for each cultivar (five seedlings per pool). Eight bunches of ‘Super Yellow’ seedlings (8/10) were confirmed to be TYLCV-infected and one to three bunches of each of the other cultivar seedlings were also infected. Viral replication in TYLCV-infected seeds and seedlings was confirmed via strand-specific amplification using virion-sense- and complementary-sense-specific primer sets. This is the first report of TYLCV seed transmission in sweet pepper plants and among non-tomato plants. Because sweet pepper is an asymptomatic host of TYLCV, seeds infected with TYLCV could act as a silent invader of tomatoes and other crops.     

侵染广西甜椒的西瓜银斑驳病毒分子鉴定

During a survey in 2019, sweet pepper plants (GXTJ) showing symptoms of ring spots and chlorotic on leaves and fruits were collected in Wuming district of Guangxi province. Serological tests by DAS-ELISA demonstrated that the GXTJ was reacted positively against to antisera of watermelon silver mottle virus (WSMoV), but negatively against to antisera of the tomato spotted wilt virus (TSWV), cucumber mosaic virus (CMV) and tobacco mosaic virus (TMV). Total RNA was extracted and 2 pairs specific primers were designed to amplify the WSMoV N gene sequence by RT-PCR. Two expected fragments (769 bp and 654 bp) were obtained from GXTJ, The results of sequence analysis showed that the sequence of N gene was 828 nt and sharing 100% identity with WSMoV isolates from Taiwan (X78556, U78734). Base on the phylogenetic analysis, the N gene sequence of WSMoV-GXTJ was grouped in the same clades as WSMoV isolates from Taiwan. These results indicate that the virus isolate from sweet pepper in Guangxi is an isolate of WSMoV.     

Phytopathogenic, morphological, genetic and molecular characterization of a Verticillium dahliae population from Crete, Greece

A population of 84?V. dahliae isolates mainly originating from Crete, Greece, was characterized in terms of pathogenicity and virulence on different hosts, in parallel with morphological/physiological characterization, vegetative compatibility grouping and mating type determination. Tomato race 2 was found to have supplanted race 1 and was more virulent on a tomato-susceptible cultivar than race 1. Using a differential host classification system which tests pathogenicity to tomato, eggplant, sweet pepper and turnip, 59 isolates were assigned to tomato, 19 to eggplant, one to sweet pepper and five to tomato-sweet pepper pathogenicity groups. All isolates from Crete fell into VCG subgroups 2A, 2B and 4B, while a remarkably high incidence of bridging isolates (compatible with two or more VCGs) was recorded. The tomato-sweet pepper pathogenicity group was morphologically quite distinct from the others, while conidial length and pigment intensity were discriminatory parameters among VCGs 2A, 2B and 4B. PCR-based molecular marker Tr1/Tr2 was reliable in race prediction among tomato-pathogenic isolates, except for members of VCG 4B, while the application of markers Tm5/Tm7 and 35-1/35-2 was highly successful for tomato-pathogenic isolates. E10 marker was related to VCG 2B, rather than to pathogenicity groups. A single nucleotide polymorphism in the ITS2 region, and two novel molecular markers, M1 and M2, proved useful for the fast and accurate determination of major VCGs 2A, 2B and 4B, and can be used for high-throughput population analyses in future studies. The mating type was unrelated to VCG classification and probably does not control heterokaryon incompatibility in V. dahliae.     

朱砂叶螨对不同蔬菜寄主的取食选择性

朱砂叶螨Tetranychus cinnabarinus寄主范围广泛,其对不同蔬菜寄主的取食选择性研究很少。本研究采用离体叶碟法和活体寄主法研究了朱砂叶螨在菜豆、茄子、番茄、黄瓜和甜椒等5种蔬菜寄主上的成螨数量、产卵数量、由卵发育至成若螨期的比例及活体寄主上叶螨数量的增长速度。结果表明,朱砂叶螨对供试的不同蔬菜寄主均可取食为害,但其对不同寄主存在取食偏好性。供试的5种寄主植物同时存在时,朱砂叶螨最喜食菜豆,在该寄主上种群发展速度最快,其次是茄子、番茄和黄瓜,在这3种寄主上的取食选择性差异不大,甜椒是该螨相对不喜食的寄主植物,但同样能够使叶螨成功完成其发育历期。离体试验和活体试验结果趋势一致。     

An inhibitor of polyamine biosynthesis — Difluoromethylornithine — and the polyamine spermidine for the control of gray mold(Botrytis Cinerea)

Difluoromethylornithine (DFMO) — an inhibitor of polyamine biosynthesis, and the polyamine spermidine (Spd) reduced gray mold of tomato, pepper, eggplant, bean andSenecio sp. leaves, and of rose petals by 37–88% when applied at 0.1–1.0 mM each. Higher doses did not result in better control. The disease was also reduced significantly on tomato fruits by 1.0 inM DFMO and by 0.1–1.0 mM Spd, and on cucumber fruits by 0.1–1.0 mM of both compounds, but not on grape berries. The combination of 0.2 mM DFMO with 1.0 mM Spd controlled gray mold ofSenecio sp. and tomato leaves additively better than either treatment alone, whereas this effect was not observed in leaves of lettuce and pepper. Ethylene production was reduced significantly by Spd applied to leaves of tomato and pepper, but not by DFMO. Linear growth and germination of the fungus were affected by lower concentrations of DFMO (ED50 0.12–0.97 and 1.4, respectively) as compared with Spd. Spermidine and DFMO controlled white mold(Sclerotinia sclerotiorum) as effectively as did the fungicide benomyl. Contribution from the Agricultural Research Organization. No. 3195-E, 1991 series.     

Pathogenicity of plant and soil isolates of <Emphasis Type="Italic">Phytophthora parasitica</Emphasis> on tomato and pepper

Crown and root rot of tomato and sweet pepper can be caused by Phytophthora parasitica. In this work, 23 P. parasitica isolates from diseased pepper or tomato plants as well as 54 isolates from 23 monocrop tomato soils (from Spain and Chile) and one from a pepper soil were studied for their host–pathogen response. Results show significant host specificity for the isolates from tomato plants and tomato soils (63 of 64 isolates were unable to cause disease in pepper). None of the pepper plant/soil isolates showed pathogenicity on tomato, and only four of 14 reproduced their pathogenicity on pepper. Only one tomato isolate was pathogenic to both Solanaceae species. Two different inoculation protocols were evaluated (substrate irrigation and stem cutting). All isolates which expressed pathogenicity when stem inoculated also did it when root inoculated, but not vice-versa. Therefore, the recommended test protocol for tomato and pepper breeding programmes is that based on root inoculation by irrigation.     

Phenolic compounds as defence response of pepper fruits to Colletotrichum coccodes

Qualitative and quantitative changes of individual and total phenolics induced by Colletotrichum coccodes fungal infection have been studied in two susceptible sweet pepper cultivars ‘Soroksari’ and ‘Bagoly’, and the role of soluble phenolic compounds in plant's defence mechanism has been evaluated. Three distinct parts were analysed on pepper fruit: healthy tissue, anthracnose lesion, and bordering tissue, and individual phenolic compounds have been identified with the use of HPLC-MS system. In pepper fruit pericarp 21 phenolic compounds have been determined; the prevalent apigenin, quercetin and luteolin glycosides, chlorogenic acid and one chrysoeriol glucoside. C. coccodes infection increased the accumulation of chlorogenic acid, chrysoeriol glucoside, quercetin and luteolin glycosides in infected bordering tissue of both analysed pepper cultivars compared to healthy pepper tissue or symptomatic spot. Total apigenin derivatives did not show a significant increase in bordering tissue compared to the healthy pepper fruit in contrast to other groups of phenolics. This suggests a lesser role of apigenin glycosides in pepper plant defence against the Colletotrichum fungus. Intense phenolic synthesis was characteristic for the bordering zone between the healthy and infected plant tissue resulting in higher total phenolic content which might hinder the fungus to spread from the infected cells into the healthy tissue.     

Root and crown rot of strawberry caused by Pythium helicoides and its distribution in strawberry production areas of Japan

Pythium species were isolated from seedlings of strawberry with root and crown rot. The isolates were identified as P. helicoides on the basis of morphological characteristics and sequences of the ribosomal DNA internal transcribed spacer regions. In pathogenicity tests, the isolates caused root and crown rot similar to the original disease symptoms. Multiplex PCR was used to survey pathogen occurrence in strawberry production areas of Japan. Pythium helicoides was detected in 11 of 82 fields. The pathogen is distributed over six prefectures.     

Corynespora leaf spot of scarlet sage caused by <Emphasis Type="Italic">Corynespora cassiicola</Emphasis>

A leaf spot disease of scarlet sage (Salvia splendens Sellow ex J.A. Shultes) found in Kanagawa and Tokyo prefectures was demonstrated to be caused by Corynespora cassiicola (Berk. and Curt.) Wei based on inoculation experiments, and morphological identification of the pathogenic fungus. Isolates of C. cassiicola from cucumber, green pepper, and hydrangea were also pathogenic to scarlet sage leaves. Although the isolates from cucumber, green pepper, and hydrangea were pathogenic to scarlet sage leaves, the scarlet sage isolate was not pathogenic to cucumber, green pepper, hydrangea, eggplant, tomato or soybean.