An Updated Host Differential Due to Two Novel Races of Diplocarpon rosae Wolf, the Causal Agent of Rose Black Spot Disease

The fungal pathogen, Diplocarpon rosae, infects only roses (Rosa spp.) and leads to rose black spot disease. Rose black spot is the most problematic disease of outdoor-grown roses worldwide due to the potential for rapid leaf chlorosis and defoliation. Eleven races of the pathogen were previously characterized from isolates collected in North America and Europe. Isolates of D. rosae obtained from infected leaves of the roses Brite EyesTM (‘RADbrite’; isolate BEP; collected in West Grove, PA) and Oso Easy® Paprika (‘CHEwmaytime’; isolate PAP; collected in Minneapolis, MN) proved to have unique infection patterns using the established host differential with the addition of Lemon FizzTM (‘KORlem’). The new races are designated race 12 (BEP) and race 13 (PAP), respectively, and Lemon FizzTM should be included in the updated host differential because it distinguishes races 7 and 12. Additionally, inconsistent infections and limited sporulation were found in the host differential Knock Out® (‘RADrazz’) for races 7 and 12. Expanding the collection of D. rosae races supports ongoing research efforts, including host resistance gene discovery and breeding new rose cultivars with increased and potentially durable resistance.

Visão computacional na agricultura: APIs de detecção e reconhecimento de doenças das plantas

As tecnologias de inteligência artificial (ia) estão permitindo identificar com mais precisão doenças em folhas de plantas por meio da análise de imagens, com efeitos benéficos sobre a agricultura (custo, eficiência, qualidade). O artigo apresenta os resultados de estudos desenvolvidos com o uso de três tecnologias (plataformas) distintas treinadas com o mesmo conjunto de 50 imagens de quatro doenças, indicando as características visuais de cada uma delas. O treinamento foi dividido em duas etapas: a primeira realizada com 30 imagens e a segunda com 20 imagens, e a validação e a análise do aprendizado foram realizadas a partir de 10 imagens. O propósito dos testes é comparar a assertividade de reconhecimento das doenças em cada tecnologia/plataforma. As doenças examinadas para o estudo são: Peronospora (downy mildew), Diplocarpon rosae (black spot), Oídio (powdery mildew) e Cancro cítrico. Os resultados mostraram-se positivos para a identificação das doenças por meio de imagens.Palavras-chave: Aprendizado de Máquinas. Agricultura Digital. Imagens Digitais. api. Visão Computacional.

Landscape Performance of Buck Roses under Minimal-input Conditions in North-central Texas

Griffith Buck (Iowa State University) bred roses (Rosa sp.) to survive long, cold winters and hot, humid summers yet still retain their foliage without fungicides. Unfortunately, there is little known about the performance of Buck roses in the southern United States. Thirty-eight Buck rose cultivars were evaluated for flowering, disease resistance, drought tolerance, and overall landscape performance in alkaline soils with no fertilizer, no pesticides, and only limited irrigation. Flowering occurred on a bimodal basis, with the highest per plant mean bloom number (16.3 blooms) and bloom coverage (9.7%) in April, and a second flowering in the fall, with 13.7 blooms per plant and 6.9% bloom coverage in October. Drought stress symptoms were most evident in October, with a wide range of symptom severity across cultivars. Black spot (Diplocarpon rosae) and powdery mildew (Podosphaera pannosa) incidence were rare across all roses and years. Landscape performance scores, rated using a 0 to 10 scale with 10 representing a perfect plant and 0 a dead plant, were highest in April (6.5) and lowest in June (4.6) and July (4.6). Landscape performance was not correlated with bloom number or coverage. While unable to recommend many of the Buck roses for north-central Texas, the cultivars April Moon and Freckles, and possibly a few other roses, can join Carefree Beauty™ (BUCbi) as recommended roses for the area.

Occurrence of pathotypes of Diplocarpon rosae on roses in Belgium

Monospore cultures of black spot (Diplocarpon rosae Wolf) were established from isolates collected on outdoor grown roses at different locations in Belgium. These monospore cultures were tested on rose cultivars and species with different levels of natural resistance to examine the possible existence of different pathotypes. For this purpose a screening protocol including scoring after artificial infection was developed on in vitro plantlets. Differences between the examined isolates proved that there exist different pathotypes of Diplocarpon rosae in Belgium.

Екологічно безпечні препарати у захисті від чорної плямистості листя троянд Diplocarpon rosae F.A. Wolf (анаморфа – Marssonina rosae (Lib.) Died.)

<p>As a result of the study of the efficacy of using biopharmaceuticals against black maculation of leaves Roses found that effectiveness of investigated of biological products during the growing season of the genus Rosa L. is 56.4±16.3% in the range from 21.1 to 72.3%. Thus, the highest values of protective action against black maculation of leaves roses had: Tryhopsyn (<em>Pseudomonas </em>and <em>Trichoderma</em> 6×10⁹ CFU/cm³) – 72.8%, Tryhodermin BT (a.s. <em>Trichoderma</em> <em>viride</em>, titer of 2×10⁹ CFU/cm³)+Planryz BT (a.s. <em>Ps. fluorescens</em> 5×10⁹ CFU/cm³) (1:1) and Tryhodermin BT (a.s. <em>Trichoderma viride</em>, titer of 2×10⁹ CFU/cm³) + Haupsyn BT (a.s. <em>Ps. aureofaciens</em> 5×10⁹ CFU/cm³) (1:1) to 72.3%, Planryz BT (a.s<em>. Ps. fluorescens</em> 5×10⁹ CFU/cm³) – 65.3%. Biologicals is restrain the development of pathology caused by causative agent <em>Diplocarpon rosae</em> F.A. Wolf on a variety of different groups of the genus <em>Rosa</em> L., namely the indicator of damage index in the samples of the group of Hybrid tea roses <em>Kardinal 85</em> Kordes, Germany (1985) was 18.2%, climbing <em>New Dawn</em> Somerset Rose Nursery, USA (1930) by 2.2%, floribunda <em>Leonardo da Vinci</em> Meilland (1993) by 6.2%, English Abraham Darby Austin, United Kingdom (1985) by 6.7% less than without processing.</p>