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.     

The use of antioxidants (free radical scavengers) to control grey mould (Botrytis cinerea) and white mould (Sclerotinia sclerotiomm) in various crops

Eighteen free radical scavengers (antioxidants) were tested for their ability to control grey mould. Most of the compounds reduced disease significantly in at least one of the test hosts–leaves of tomato, pepper, Senecio sp., bean, eggplant, or rose flowers; however, the effective concentration varied between 0.1 and 100 m m . Selected antioxidants were tested further. Butylated hydroxy toluene (BHT), tannic acid, ascorbic acid and dimethyl sulfoxide (DMSO) at a concentration of 1 .0 m m controlled grey mould of tomato fruits. All these compounds except BHT controlled the disease on cucumber fruits. Antioxidants affected Rhizopus stolonifer on grape berries but not Botrytis cinerea or Aspergillus spp. Some combinations of antioxidants were found to be more effective than either compound alone when tested on pepper or tomato. The synergists ascorbic acid and citric acid improved the control activity of BHT, propyl gallate, benzoic acid and tert -butylhydroquinone on tomato leaves. Ethylene production was inhibited in tomato leaves treated with propyl gallate, ascorbic acid and benzoic acid, but not in pepper leaves. Ethephon or H₂O₂ increased the severity of grey mould on leaves of Senecio sp. Their effect was controlled by BHT and benzoic acid or by BHT, respectively. Four to six compounds reduced linear growth of B. cinerea isolates in culture at a concentration of 1.0 m m , and six more compounds were effective at 10.0 m m . However just five compounds inhibited conidial germination at the high concentration alone. Gluconic acid lactone, thiourea and propyl gallate reduced Sclerotinia sclerotiomm on lettuce by 51-76%. The multiple activity of antioxidants on the host plant interaction is discussed.     

The involvement of ethylene and calcium in gray mold of pelargonium,ruscus, and rose plants

Leaves ofPelargonium domesticum andRuscus hypoglossum infected byBotrytis cinerea Pers., produced 12 and 1.5 nl ethylene/h/g, respectively, 34 days after inoculation; wounded or healthy leaves and phyloclades of them produced much lower amounts. When the fungus was grown on dead leaves it produced negligible amounts of the gas even when supplemented with methionine. Exogenous ethylene enhanced gray mold development in both hosts. Silver thiosulfate, aminooxyacetic acid (AOA) and aminoethoxyvinylglycine significantly inhibited disease development in pelargonium, and the latter two compounds inhibited ethylene production. AOA inhibited disease development and ethylene production in cut rose flowers; calcium ions inhibited disease development whereas the chelator EGTA [ethylene glycol bis-(β-aminoethyl ether)N,N,N′,N′-tetraacetic acid] enhanced it. Disease suppression by an excess of Ca²⁺ was correlated with repression of ethylene production by the flowers, whereas deficiency in Ca²⁺ increased disease severity. Publication of the Agricultural Research Organization. No. 2413-E, 1988 series.     

Control of infection and sporulation ofBotrytis cinerea on bean and tomato by saprophytic bacteria and fungi

Sixty isolates of saprophytic microorganisms were screened for their ability to reduce the severity of grey mould (Botrytis cinerea) infection and sporulation. Isolates of the bacteriaXanthomonas maltophilia, Bacillus pumilus, Lactobacillus sp., andPseudomonas sp. and the fungusGliocladium catenulatum reduced germination of conidia of the pathogen and controlled disease on bean and tomato plants. Their activity under growth room conditions was good, consistent, and similar to the activity of the known biocontrol agent,Trichoderma harzianum T39 (non-formulated). Although the tested isolates may for nutrients with the germinating conidia ofB. cinerea, resistance induced in the host by live or dead cells were also found to be involved. Inhibitory compounds were not detected on treated leaves. Sporulation ofB. cinerea after its establishment on leaves was also reduced by the above mentioned isolates and byPenicillium sp.,Arthrinium montagnei, Ar. phaeospermum, Sesquicillium candelabrum, Chaetomium globosum, Alternaria alternata, Ulocladium atrum, andT. viride. These sporulation-inhibiting fungi did not reduce the infection of leaves byB. cinerea. Most of these selected fungi and bacteria were capable of reducing lesion expansion.     

湖北省设施番茄灰霉病发生规律及流行因子分析

为探索湖北省设施番茄灰霉病的发生规律,揭示不同流行因子与番茄灰霉病发生的关系。于2013-2016年在湖北省武穴市吴谷英村番茄种植基地选取代表性番茄大棚进行调查和取样检测,结果表明:湖北省设施番茄叶片和花朵带菌率变化起伏较大,带菌率分别为0～90.0%和0～100.0%;叶片带菌率在3月下旬到4月中下旬和5月中下旬是高峰期;花朵带菌率在4月中旬和5月中下旬达到高峰期,总体上花朵带菌率较高。番茄不同组织灰霉病的发病时间不同,叶片首先开始发病,花、果实、茎秆再逐渐发病,花朵和果实的发病率相对较高,叶片和茎秆发病率较低;花朵和果实发病率均在5月中旬至6月初达到最大值,茎秆发病率于5月下旬至6月上旬达到最高值,叶片无明显发病高峰期。果实、叶片、花朵和茎秆的发病率分别为0～42.0%、0～24.7%、0～100.0%和0～32.0%。番茄叶片发病率、花朵发病率、茎秆发病率和相对湿度均与果实发病率呈显著相关;通过预测模型检验表明相对湿度和叶片发病率所建模型预测值和实际值符合程度较好。在湖北省设施番茄大棚中,叶片发病率、花朵发病率、茎秆发病率和相对湿度对番茄果实发病影响最为显著,在防治过程中应及时摘除发病组织,调控棚内环境条件,预防灰霉病发生。     

Invasiveness ofPseudomonas solanacearum in tomato,eggplant and pepper: a comparative study

The colonization of eggplant, pepper and tomato byPseudomonas solanacearum was compared. Latent infections were observed in pepper and eggplant, indicating that this phenomenon was general in the main hosts ofP. solanacearum. In eggplant and pepper, as in tomato, resistance did not arise from a resistance to root colonization by the bacteria. In tomato and eggplant, resistance mechanisms appeared to be similar: spread ofP. solanacearum was limited in resistant cultivars. In contrast, in pepper this limitation was not observed and plants appeared more tolerant to high bacterial populations than tomato and eggplant.     

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.     

Ornamental plants and thrips populations associated with tomato spotted wilt virus in Greece

A survey was conducted in order to record the ornamental plants that are hosts of tomato spotted wilt virus (TSWV) and impatiens necrotic spot virus (INSV) in Greece. Polyclonal antibodies prepared against the N protein of a Greek isolate of TSWV fromGerbera jamesonii (GR-34) were used. Leaf samples were taken from plants showing typical symptoms of tospovirus infection such as chlorotic and necrotic rings on the leaves and malformation and necrosis of the flowers. The samples were tested by double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) using polyclonal antibodies to the N proteins of TSWV and INSV (NL-07). ELIS A-positive samples were mechanically transmitted to plants ofPetunia hybrida, Nicotiana rustica andN. benthamiana to confirm infection. Although none of the samples was found infected with INSV, TSWV presence was recorded in 42 botanical species that belong to 40 genera in 27 families. Among them the speciesBeloperone guttata, Coleus barbatus, Impatiens petersiana andLilium auratum are reported for the first time as hosts of TSWV, whereasBegonia sp.,Catharanthus roseus Celosia cristata, Dianthus chinensis, Fuchsia hybrida andStephanotis floribunda are found as new hosts of the virus in Greece. Thrips collected from TSWV-infected plants were in most cases identified asFrankliniella occidentalis, except from plants ofDendranthema sp. andDianthus caryophyllus whereThrips tabaci individuals were also identified. Different percentages of transmitters were noticed when the thrips populations collected from TSWV-infected ornamental hosts were tested for transmission of TSWV.     

Seedborne fungi detected on stored solanaceous berry seeds and their biological activities

We isolated 629 fungi from 1296 berry seeds of solanaceous plants, including tomato (Lycopersicon esculentum), eggplant (Solanum melongena), bell pepper (Capsicum annuum), and red pepper (Capsicum annuum var. annuum) preserved for long and short terms. The isolates were classified into 22 genera excluding unidentified fungi, and the fungal floras were divided into two types: the tomato–eggplant and pepper groups. The results of cluster analysis with unweighted pair-group method with arithmetic average also supported these groups. Most tomato seeds infested with Geotrichum candidum germinated and grew the same as uninfested seeds. Cladosporium sphaerospermum and Arthrinium sp. isolated from eggplant seeds strongly suppressed germination, and Penicillium variabile suppressed seminal root elongation on eggplant. Alternaria alternata, Botrytis cinerea, and Myrothecium verrucaria detected from red pepper or bell pepper seeds were pathogenic to the fruits and the seedlings after artificial inoculation.     

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.     

Selection and evaluation of phyllosphere yeasts as biocontrol agents against grey mould of tomato

Phyllosphere yeasts antagonistic to the infective activity of Botrytis cinerea were isolated from leaves of greenhouse-grown tomatoes and evaluated in a detached leaf assay for their ability to suppress grey mould. Nine of 30 recovered yeast isolates were found to reduce a disease index by >90% when compared to an untreated control. In greenhouse experiments, the yeast isolate Rhodotorula glutinis Y-44 was the most efficient in controlling grey mould of tomato plants. In further experiments in greenhouse-grown tomato plants the effectiveness of R. glutinis Y-44 was compared with two commercial fungicides. It was demonstrated that R. glutinis Y-44 was as effective as fungicides in controlling the pathogen. Moreover, the population of R. glutinis Y-44 was monitored for 8 weeks after application on tomato plants. The isolate successfully colonized the plant surface, although the population decreased by 10-fold 8 weeks after application. Since B. cinerea is also a major post-harvest pathogen for tomato fruits, the ability of R.␣glutinis Y-44, to protect artificially infected wounded tomato fruits was also tested. It was shown that R.␣glutinis Y-44 was able to reduce by 50% the percentage of infected wounds compared to the untreated controls.     

Control of grey mould (Botrytis cinerea) with film-forming polymers

Several film-forming polymers reduced the amount of grey mould on various crops in a dew chamber and in a plastic house under natural conditions. The polymers Wilt Pruf, Biofilm and Colfix reduced germination of conidia and germ tube length of Botrytis cinerea . The most effective inhibition of linear growth of the pathogen on potato dextrose agar was obtained by Safe Pack and Biofilm. All polymers significantly reduced grey mould on detached leaves of Capsicum, Phaseolus , tomato, cucumber, rose and pelargonium. Grey mould on rose flowers was not controlled, apparently due to latent infection. The substances Biofilm and Vapor Gard were applied either alone or with chlorothalonil fungicide on cucumber plants in a commercial greenhouse. The polymers had no harmful effect to the host. Disease on senescing female fruits of cucumber was reduced by 46–67% with no additive effect to the mixture with fungicides. Stem infection also was reduced.     

Honey bee dispersal of the biocontrol agent Trichoderma harzianum T39: effectiveness in suppressing Botrytis cinerea on strawberry under field conditions

Botrytis cinerea, which causes grey mould, is a major pathogen of many crops. On strawberry, isolates of Trichoderma spp. can effectively control B. cinerea, but frequent application is necessary. Bees can be used to disseminate biological control agents to the target crop. We tested the ability of honey bees to disseminate Trichoderma harzianum T39 to control B. cinerea in strawberry in the field during the winter in Israel over two consecutive seasons. We used the recently developed ‘Triwaks’ dispenser for loading the bees with the T. harzianum inoculum. During both years, grey mould developed in late January in untreated control plots; at low to medium disease levels it was partially controlled by fungicide treatment, and was best controlled in bee-visited plots. At high disease levels neither chemical nor biological control was effective. To assess the spatial distribution of inoculum by bees, we sampled flowers up to 200 m from the hives and found effective levels of T. harzianum even at 200 m. The approach used in this study provides an effective control of grey mould in strawberry in conditions of low to medium grey mould incidence.     

Phylogenetic analyses of plant-growth-promoting rhizobacteria isolated from tomato,lettuce, and Japanese pepper plants in Hyogo Prefecture,Japan

Approximately 30,000 fluorescent bacterial strains isolated from tomato, lettuce, eggplant, Chinese cabbage, and Japanese pepper plants at seven different locations in Hyogo Prefecture, were screened for plant-growth-promoting (PGP) activity to induce disease resistance against bacterial wilt in tomato. The 37 strains that had higher PGP activity were subjected to molecular phylogenetic analyses using the sequences of the 16S rRNA, gyrB and rpoD genes. Most of the strains were identified as Pseudomonas fluorescens or its close relative, P. putida, while a few strains were grouped with more distantly related bacterial species such as Enterobacter and Stenotrophomonas. The phylogenetic relationships among tomato and lettuce isolates mostly coincided with the source locality and host plants, with a few exceptions. In contrast, isolates from Japanese pepper plants did not form their own cluster but represented several different bacterial species.     

Epidemiology of Grey Mould in Annual Waiting-bed Production of Strawberry

The epidemiology of Botrytis cinerea was studied in five annual strawberry crops using waiting-bed transplants, a system widely adopted in the Netherlands. On dead leaves of transplants the incidence of B. cinerea varied from 26.7% to 52.6%, but the leaf area with potential sporulation was low (3.5–15.6%). During each crop cycle, the availability of necrotic leaf substrate for spore production of B. cinerea was generally low and varied between seasons and with the quality of transplants. B. cinerea sporulated on a maximum of 15.5 cm² of leaf area per plant, measured as potential sporulation. The aerial concentration of B. cinerea conidia in untreated plots did not differ from the concentration in plots where all dead leaves had been removed, nor from the concentration at 25–50 m distance from the strawberry plots. B. cinerea incidence on flowers ranged from 5% to 96%, but no correlation was found with the potential spore production on necrotic leaves. Grey mould at harvest varied from 1.4% to 11.3% and was correlated with the average precipitation during the harvesting period but not with B. cinerea incidence on flowers. Post-harvest grey mould ranged from 2.1% to 32.6% and was correlated with petal colonisation by B. cinerea. The results suggest that in the annual cropping system with waiting-bed transplants, necrotic leaves are not a significant source of B. cinerea inoculum, unlike in other strawberry production systems. Therefore, control measures of grey mould in this annual system should focus on protection of flowers and young developing fruits, and not on the reduction of inoculum production on leaf debris.     

Host range comparison of the causal agents of pepper yellow vein and lettuce big vein

A number of solanaceous and composite plant species were tested as hosts for the causal agents of pepper yellow vein (PYVA) and lettuce big vein (LBVA), transmitted by a pepper and a lettuce isolate ofOlpidium brassicae, respectively. The agents had the following artificial hosts in common:Lycopersicon esculentum, Solanum melongena, Physalis floridana, Nicandra physaloides, Lactuca sativa, Sonchus oleraceus andL. virosa. Capsicum annuum, S. villosum, S. nigrum, Crepis vesicaria andSenecio vulgaris were infected by PYVA, but not by LBVA.Cichorium endivia andTaraxacum officinalis were not infected by any of the two agents.N. physaloides, although not colonized by the pepper isolate ofOlpidium, still became infected by PYVA.     

Molecular and Pathogenicity Characteristics of Phytophthora nicotianae Responsible for Root Necrosis and Wilting of Pepper (Capsicum annuum L.) in Tunisia

Isolates of Phytophthora from pepper, produced in Tunisia, were characterised according to molecular and pathogenicity criteria. Polymerase chain reaction amplification of the ITS1 region in the ribosomal DNA resulted in different sized fragments. The pepper isolates and P. nicotianae yielded a fragment of 310bp that distinguished it from P. capsici with a fragment of 270bp. The ribosomal RNA gene amplicons of both internal transcribed spacers and the 5.8 S of the pepper Phytophthora and P. nicotianae were digested with 8 endonucleases. The patterns generated, with the 2 enzymes that cut, were identical for both taxa. This molecular analysis corroborated the morphological and biological characteristics and suggests strongly that the isolates of Phytophthora from pepper belong to the species P. nicotianae. Inoculation of pepper, tomato, eggplant and tobacco plants with the isolates of P. nicotianae from pepper showed they were highly pathogenic on pepper but not on tobacco, while their pathogenicity was weak on tomato and eggplant and was associated with atypical symptoms not observed in the field. These pathogenicity tests suggest that pepper isolates of P. nicotianae are particularly adapted to their host and may thus constitute a forma specialis of P. nicotianae.     

棉铃虫雌成虫对16种植物的产卵偏好性及幼虫取食后的生存表现

为研究棉铃虫成虫寄主偏好性和幼虫取食后生存表现之间的关系,明确两者在决定寄主过程中的作用,我们测定了交配后的棉铃虫雌成虫对16种植物(棉花、玉米、大豆、花生、番茄、辣椒、茄子、烟草、黄瓜、胡萝卜、西芹、杨树、月季、菠菜、包菜、大葱)的产卵偏好性和幼虫取食这些植物嫩叶后的存活和发育情况。棉铃虫雌成虫选择在烟草、茄子、棉花、胡萝卜、番茄、辣椒、玉米、西芹、大豆和花生等10种植物上产卵,但只有取食西芹、烟草、番茄、大豆、棉花和胡萝卜等6种植物叶片的初孵幼虫能够完成幼虫阶段的生长发育、化蛹并羽化,且取食植物嫩叶的幼虫的存活率、发育历期、蛹期和蛹重均差于取食人工饲料的幼虫。以上结果表明,棉铃虫雌成虫产卵寄主与其幼虫取食寄主之间存在并非一一对应的关系,幼虫的生存表现限定了棉铃虫的寄主范围。     

Host Range Specificity in Verticillium dahliae

ABSTRACT Verticillium dahliae isolates from artichoke, bell pepper, cabbage, cauliflower, chili pepper, cotton, eggplant, lettuce, mint, potato, strawberry, tomato, and watermelon and V. albo-atrum from alfalfa were evaluated for their pathogenicity on all 14 hosts. One-month-old seedlings were inoculated with a spore suspension of about 10(7) conidia per ml using a root-dip technique and incubated in the greenhouse. Disease incidence and severity, plant height, and root and shoot dry weights were recorded 6 weeks after inoculation. Bell pepper, cabbage, cauliflower, cotton, eggplant, and mint isolates exhibited host specificity and differential pathogenicity on other hosts, whereas isolates from artichoke, lettuce, potato, strawberry, tomato, and watermelon did not. Bell pepper was resistant to all Verticillium isolates except isolates from bell pepper and eggplant. Thus, host specificity exists in some isolates of V. dahliae. The same isolates were characterized for vegetative compatibility groups (VCGs) through complementation of nitrate nonutilizing (nit) mutants. Cabbage and cauliflower isolates did not produce nit mutants. The isolate from cotton belonged to VCG 1; isolates from bell pepper, eggplant, potato, and tomato, to VCG 4; and the remaining isolates, to VCG 2. These isolates were also analyzed using the random amplified polymorphic DNA (RAPD) method. Forty random primers were screened, and eighteen of them amplified DNA from Verticillium. Based on RAPD banding patterns, cabbage and cauliflower isolates formed a unique group, distinct from other V. dahliae and V. albo-atrum groups. Minor genetic variations were observed among V. dahliae isolates from other hosts, regardless of whether they were host specific or not. There was no correlation among pathogenicity, VCGs, and RAPD banding patterns. Even though the isolates belonged to different VCGs, they shared similar RAPD profiles. These results suggest that management of Verticillium wilt in some crops through crop rotation is a distinct possibility.     

Weed hosts of <Emphasis Type="Italic">Verticillium dahliae</Emphasis> in cotton fields in Turkey and characterization of <Emphasis Type="Italic">V. dahliae</Emphasis> isolates from weeds

A weed survey conducted in 2004 and 2005 in Aydin province of Turkey showed that Solanum nigrum, Xanthium strumarium, Amaranthus retroflexus, Portulaca oleracea, Sonchus oleraceus and Datura stramonium were the most prevalent weeds in the cotton fields exhibiting Verticillium wilt. Verticillium dahliae Kleb. was recovered from A. retroflexus and X. strumarium in those cotton fields. This is the first report of V. dahliae occurring naturally in A. retroflexus in Turkey. Pathogenicity tests on cotton and weeds showed that the virulence of V. dahliae isolates from weeds was higher on cotton plants than on weeds, with the disease severity ranging from 31.7% to 98.0%. Disease severity of V. dahliae isolates was 54.7–93.9% on eggplant, 23.7–51.6% on cucumber and 11.0–16.4% on tomato, whereas it did not cause any disease symptoms, or only low levels, on pepper and bell pepper. Two vegetative compatibility groups (VCGs) were identified among seven tested weed isolates: VCG2A (two isolates) and VCG2B (three isolates) using international reference strains.