Cultivar and Spacing Effects on Transmission of <i>Phytophthora parasitica</i> in an Ebb-and-Flow Subirrigation System

Strong, Stephen S; Behe, Bridget K.; Deneke, C. Fred; Bowen, Kira L.; Keever, Gary J.

doi:10.1094/pdis.1997.81.1.89

Cited by 28 publications

(14 citation statements)

References 12 publications

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“…These plants were grown in pots on solid-top benches and the noninoculated controls presum ably became infected by zoospores flushed out of the bottom of the pots, reaching adjacent pots via bench surface water flow. Similarly, P. parasitica was shown to be disseminated from containerized Catharanthus roseus plants growing in soil infested with zoospores on greenhouse benches watered via an ebb-and-flow subirrigation system (63). Such observations again demonstrate the ease with which zoospores can move in water and prompted the switch to open-mesh bench tops in the current experiments.…”

Section: Discussionsupporting

confidence: 67%

Etiology of a Tuber Rot and Foliar Blight of Potato Caused by Phytophthora nicotianae

2015

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Taylor, R. J., Pasche, J. S., and Gudmestad, N. C. 2015. Etiology o f a tuber rot and foliar blight of potato caused by Phytophthora nicotianae. Plant Dis. 99:474-481. Although Phytophthora nicotianae is not normally considered to be an important pathogen of potato (Solanum tuberosum), intermittent out breaks o f a foliar blight and tuber rot have been reported in the United States over the past 75 years. Due to the sporadic nature of these reports, little is known about the etiology o f the disease in potato. However, foliar disease and tuber rots caused by this pathogen are usually centered near areas of standing water in the field and along pivot tracks. Moreover, soil particles adhering to the foliage o f infected potato plants suggest that wa ter splash is involved in P. nicotianae dissemination and infection. Soil infestation and water splash dissemination studies were conducted under greenhouse conditions to examine the role that zoospores of P. nicotia nae may play in disease on potato. In the soil infestation study, inoculum of P. nicotianae was added to soil at four rates (0.0, 1.0 x 1 0 ,5 .0 x 103, and 4.0 x 104 zoospores/ml) and three timings (at planting and 7 and 14 days after planting). Direct infection o f aboveground plant tissues was achieved via splash dissemination of inoculum onto potato foliage. All soil infestations significantly reduced emergence, with the exception of the 1.0 x 103 zoospores/ml treatment, and no plants emerged from soil infested with 4.0 xlO 4 zoospores/ml. Significant reductions in stem num ber were observed with infestations of 1.0 x 103 and 5.0 x 103 zoospores/ ml at planting and 5.0 x 103 zoospores/ml at 7 days after planting. Prog eny tuber infections were confirmed with infestations at 1.0 x 103 zoospores/ml at planting and 7 days after planting. Lesions developed on leaflets, petioles, leaf axils, and stems in all water splash dissemination treatments within 3 days o f inoculation, significant differences in the le sion number were observed, and disease severity generally was propor tional to inoculum concentration. Relative area under the disease progress curve o f the 5.0 x 103 and 4.0 x 104 zoospores/ml splash dis semination treatments was significantly greater than the 0.0 zoospore and 1.0 x 103 zoospores/ml treatments. Progeny tuber infections were ob served with all water splash dissemination treatments but infection rates did not differ significantly among treatments. These studies confirm the hypothesis that water splash dissemination of P. nicotianae inoculum is a likely means by which infections of this pathogen are initiated in potato. The oomycete Phytophthora nicotianae Breda de Haan (= P. parasitica D astur) is a p a thogen w ith an extensive and diverse ho st range that encom passes num erous fam ilies o f w oody and flow ering p lan ts and is capable o f infecting o v e r 300 species (14). T his pathogen com m only causes ro o t and crow n rots, the m ost notable o f w hich are b lack shank o f tobacco (70) as w ell as foot rot, gum m osis, and roo...

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Section: Discussionsupporting

confidence: 67%

Etiology of a Tuber Rot and Foliar Blight of Potato Caused by Phytophthora nicotianae

2015

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“…(1,4,34,46,48,53). A particularly high risk of disease spread is associated with the collection, recycling, and reuse of irrigation water, often referred to as recirculation (45,57,58), which is becoming more popular as attempts are increasingly being made to conserve valuable water supplies. Rapid dispersal of the pathogen in water is often achieved by asexual flagellate zoospores, and a key element for pathogen control is the removal of zoospores from water supplies.…”

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confidence: 99%

Spatial and Temporal Analysis of the Microbial Community in Slow Sand Filters Used for Treating Horticultural Irrigation Water

Calvo-Bado

Pettitt

Parsons³

et al. 2003

Appl Environ Microbiol

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An experimental slow sand filter (SSF) was constructed to study the spatial and temporal structure of a bacterial community suppressive to an oomycete plant pathogen, Phytophthora cryptogea. Passage of water through the mature sand column resulted in complete removal of zoospores of the plant pathogen. To monitor global changes in the microbial community, bacterial and fungal numbers were estimated on selective media, direct viable counts of fungal spores were made, and the ATP content was measured. PCR amplification of 16S rRNA genes and denaturing gradient gel electrophoresis (DGGE) were used to study the dynamics of the bacterial community in detail. The top layer (1 cm) of the SSF column was dominated by a variable and active microbial population, whereas the middle (50 cm) and bottom (80 cm) layers were dominated by less active and diverse bacterial populations. The major changes in the microbial populations occurred during the first week of filter operation, and these populations then remained to the end of the study. Spatial and temporal nonlinear mapping of the DGGE bands provided a useful visual representation of the similarities between SSF samples. According to the DGGE profile, less than 2% of the dominating bands present in the SSF column were represented in the culturable population. Sequence analysis of DGGE bands from all depths of the SSF column indicated that a range of bacteria were present, with 16S rRNA gene sequences similar to groups such as Bacillus megaterium, Cytophaga, Desulfovibrio, Legionella, Rhodococcus rhodochrous, Sphingomonas, and an uncharacterized environmental clone. This study describes the characterization of the performance, and microbial composition, of SSFs used for the treatment of water for use in the horticultural industry. Utilization of naturally suppressive population of microorganisms either directly or by manipulation of the environment in an SSF may provide a more reproducible control method for the future.Fungal plant diseases are a major problem within the horticultural industry, resulting in reduced yields and occasionally major crop damage. Contaminated irrigation water has long been recognized as an important source of fungal plant pathogens and is an important factor in disease spread on commercial horticultural nurseries (4). Water from many commonly used sources, such as rainwater from glasshouse roofs and, in particular, water stored in open reservoirs and ponds, can often contain large numbers of infective propagules of fungal plant pathogens, such as Pythium and Phytophthora spp. (1,4,34,46,48,53). A particularly high risk of disease spread is associated with the collection, recycling, and reuse of irrigation water, often referred to as recirculation (45,57,58), which is becoming more popular as attempts are increasingly being made to conserve valuable water supplies. Rapid dispersal of the pathogen in water is often achieved by asexual flagellate zoospores, and a key element for pathogen control is the removal of zoospores from water supplies. A wide...

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“…Quando a irrigação é completada, a água não utilizada é drenada de volta ao reservatório para posterior recirculação pelo sistema (STRONG et al, 1997;DUMROESE et al, 2006). Já que o sistema é fechado, uma redução em 86% de uso da água foi conseguida em subirrigação comparado com irrigação sobrecopa em culturas alimentares (AHMED; CRESSWELL; HAIGH, 2000), e a perda de fertilizantes para o solo é, praticamente, eliminada, já que a água lixiviada é recirculada, impedindo que fertilizantes e pesticidas atinjam os lençóis superficiais e profundos.…”

Section: Introductionunclassified

Eficiência De Sistemas De Irrigação Em Mudas De Espécies Florestais Nativas Produzidas Em Tubetes

Thebaldi¹,

Lima²,

Silva³

et al. 2016

Ciênc. Florest.

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RESUMOA baixa qualidade de mudas pode advir de problemas na irrigação e/ou nutrição das mudas em sua fase de formação em viveiros. Em relação à irrigação, problemas podem surgir referentes à má distribuição da água ou mesmo seu manejo, levando ao deficit ou ao excesso de irrigação, enquanto o excesso pode lixiviar nutrientes, o deficit pode prejudicar o desenvolvimento da planta. Assim, o presente trabalho teve como objetivos avaliar a eficiência de irrigação de um sistema de irrigação por microaspersão já instalado em um viveiro de mudas de espécies florestais e também avaliar a eficiência de um sistema de subirrigação de mudas florestais nativas cultivadas em tubetes. A avaliação da eficiência da microaspersão foi realizada em um viveiro de mudas de espécies nativas florestais na cidade de Itutinga -MG, o delineamento utilizado foi o inteiramente casualizado (DIC) em esquema de parcelas subdivididas, estando o equipamento de irrigação na parcela (três níveis: MA-20, Rondo e Inverted Rotor Spray) e três espécies florestais na subparcela. Na avaliação de eficiência em tubetes de 300 cm³, as categorias da subparcela foram: araucária (Araucaria angustifolia (Bert.) O. Ktze.), jerivá (Syagrus romanzoffiana (Cham.) Glassman) e cutieira (Joannesia princeps Vell.). Em tubetes de 110 cm³ os três níveis da subparcela foram as espécies: mutamba (Guazuma ulmifolia Lam.), angico-vermelho (Anadenanthera macrocarpa Benth.) e peroba-rosa (Aspidosperma polyneuron Muell.). A avaliação da eficiência da subirrigação foi realizada em uma estufa localizada na Universidade Federal de Lavras, em dois tanques de subirrigação em três repetições. As maiores eficiências de aplicação foram obtidas para o emissor modelo MA-20. Não houve diferenças significativas entre a eficiência de aplicação dos microaspersores em relação às espécies estudadas, em ambos os tubetes. A eficiência de irrigação no tanque de tubetes de 300 cm³ foi 90,42%, enquanto para tubetes de 110 cm³ foi 92,17%. Os tanques de subirrigação mostraram-se como alternativa interessante para irrigação de mudas das espécies florestais testadas, apresentando alta eficiência para os dois tamanhos de tubetes avaliados. Palavras-chave: viveiro; subirrigação; microaspersão. ABSTRACTSeedlings low quality can result due to problems in irrigation and/or nutrition of seedlings in their nursery phase. Regarding irrigation, problems can arise related to low uniformity of water application or its management, leading to lack or excess of water. While the excess can leach nutrients, the deficit can affect plant growth. Thus, this work had as objective to evaluate irrigation efficiency of a microsprinkler irrigation system at a forest native species nursery and also at sub-irrigation of forest native species being raised in recipient tubes The microsplinkler irrigation efficiency evaluation was performed in a native forest nursery at Itutinga -MG city, held in completely randomized design in split plots scheme, with the irrigation equipment

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Cultivar and Spacing Effects on Transmission of Phytophthora parasitica in an Ebb-and-Flow Subirrigation System

Cited by 28 publications

References 12 publications

Etiology of a Tuber Rot and Foliar Blight of Potato Caused by Phytophthora nicotianae

Etiology of a Tuber Rot and Foliar Blight of Potato Caused by Phytophthora nicotianae

Spatial and Temporal Analysis of the Microbial Community in Slow Sand Filters Used for Treating Horticultural Irrigation Water

Eficiência De Sistemas De Irrigação Em Mudas De Espécies Florestais Nativas Produzidas Em Tubetes

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