Dynamics of spread and control of cercospora (Cercospora beticola Sacc.) and ramularia (Ramularia beticola Fautrey and F.Lamb.) leaf spot in sugar beet crops

Abstract

Dynamics of spread of the most destructive sugar beet foliar diseases cercospora (Cercospora beticola Sacc.) and ramularia (Ramularia beticola Fautrey & F.Lamb.) leaf spot and efficacy of six fungicides used for their control were investigated at Rumokai Research Station of Lithuanian Research Centre for Agriculture and Forestry during 2011-2012. The crop was sprayed with fungicides once after the first symptoms of foliar diseases had been spotted. In the experimental years, cercospora leaf spot started to spread in the sugar beet crops on the 31 st of July -3 rd of August. During the 1 st assessment the disease incidence was 4.3-19.2% and the disease severity was 0.01-0.08%. Further progress of cercospora leaf spot was influenced by the weather conditions: with the weather being wet and warm the disease development was rapid and 10-11 weeks after the 1 st assessment the disease incidence reached 90.0-98.3%, and the disease severity was 10.98-11.91%. Ramularia leaf spot started to spread at the same time as cercospora leaf spot; however, its severity was lower. The progress of ramularia leaf spot was weaker than that of cercospora leaf spot and before harvesting ramularia leaf spot severity reached 1.75-1.79%. The highest efficacy against both diseases was exhibited by the fungicides containing epoxiconazole -Maredo, Opera N, Tango super.

Improved phyllosphere microbiome composition of tea plant with the application of small peptides in combination with rhamnolipid

“…The amplification of this advantageous fungus through the administration of small peptides could potentially suppress pathogen infection and support healthy plant growth and development [ 26 ]. Conversely, although no studies have directly shown that Ramularia can cause tea plant diseases, studies have shown that Ramularia can cause diseases in many plants, including but not limited to barley, beets and strawberries [ 27 , 28 ]. Therefore, this risk can be given due attention when using small peptides as foliar fertilizers.…”

Fungicidal Protection as Part of the Integrated Cultivation of Sugar Beet: An Assessment of the Influence on Root Yield in a Long-Term Study

“…In integrated protection, after using non-chemical methods and treatments, foliar fungicides are also applied [37,38]. These preparations, properly selected and applied in accordance with the principles of good agricultural practice, improve the health of plants and reduce losses caused by diseases [39,40]. Their use in their own study area was justified.…”

Efficacy of fungicides in sugar beet crops

“…Assessments of the disease severity were done three times on the 1 st of August (before fungicide application), on the 1 st of September (a month after the first fungicide application) and on the 1 st of October (a month after the second fungicide application). Disease severity was estimated by establishing the diseaseaffected leaf area in per cent according to the scale: 0, 1, 2, 5, 10, 25, 35, 45 and 60 (EPPO Standards, 2004;Baltaduonytė et al, 2013). The disease severity (R) was calculated according to the formula:…”

“…where a is disease severity in the control treatment, b -disease severity in the fungicide applied treatment (Baltaduonytė et al, 2013).…”

“…Fungicides are the most effective at the beginning of disease emergence so we need to apply the right disease diagnostics methods, precise evaluation of meteorological conditions and plant growth stages. For the prevention of plant pathogens resistance to the fungicide used, it is recommended to use products containing different active ingredients (Secor et al, 2010;Baltaduonytė et al, 2013). The objectives of our investigations were: 1) to evaluate the severity of fungal diseases; 2) to establish the efficacy of various active ingredients of fungicides, their application timing and doses on the severity of the main fungal diseases in the sugar beet crops; 3) to evaluate sugar beet yield and quality of roots.…”