Chemical control of Ramulosis in cotton. Controle químico de Ramulose no algodoeiro.
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Transcript of Chemical control of Ramulosis in cotton. Controle químico de Ramulose no algodoeiro.
Chemical Control
Ramulosis in cotton
Glomerella gossypii (Colletotrichum gossypii var. cephalosporioides)
By Vinicius Garnica
• Shrub plant native from tropical and subtropical regions around the world, including the Americas, Africa, and India
• Most widely used natural fiber cloth in clothing today
• China is the biggest importer with approximately 14,1 million 480 lb. in 2013/2014
• $5.20 billion in crop value in U.S.
National Cotton Council of America. Retrieved from http://www.cotton.org/econ/world/detail.cfm
Cotton
Source: USDA
Million 480 BalesMillion 480 Bales
Anthracnose in cotton
• Caused by Glomerella gossypii (Colletotrichum gossypii)
• Host specificity, only affects cotton• Cultivars vary in level of severity
• G. gossypii probably indigenous to America, now occurs in most cotton-growing areas throughout the world but tends to be localized in the higher rainfall areas.
• Scald-like lesions in stems and leaves. Also causes damping off on seedling
• Infected bolls develop small, round, water-soaked spots which rapidly enlarge, become sunken and finally develop reddish borders with pink centres
OEPP/EPPO (1982) Data sheets on quarantine organisms No. 71, Glomerella gossypii. Bulletin OEPP/EPPO Bulletin 12 (1).
Guo Shupu, II-AAAS
Anthracnose in cotton
http://www.plantwise.org/KnowledgeBank/Datasheet.aspx?dsid=25358
• Colletotrichum gossypii var. cephalosporioides differs from C. gossypii var. gossypii in invirulence, aggressiveness, morphology, growth on various media and ability to develop at less than 30°C.
• C. gossypii var. cephalosporioides causes ramulosis or witches' broom disease and it only was reported in Brazil and Paraguay, so far, whereas C. gossypii var. gossypii occurs world-wide.
Follin, J.C. (1970) Spécialisation physiologique chez Colletotrichum gossypii South. Coton et Fibres Tropicales 25, 387-388.
Photo: FMC. Manual of Cotton Diseases
Two different etiological agents
Ramulosis• Yield losses averaging 20-38%
• Most economic limiting disease in Brazilian cottony industry
• C. gossypii var. cephalosporioides survives saprophytically as micellium in decaying plant material
• Main source of inoculum contaminated seeds
• Conidia embedded in water-soluble mucilage are rain splashed onto leaves
• Infection favored by temperatures between 25-30C , high humidity and wounding caused
Kimati, H., Amorim, A., Bergamim, F. A. 1997. Manual de Fitopatologia, Vol.2: Doenças de Plantas Cultivadas. Editora Agronomia Ceres.
Cassetari Neto, D.; Santos, E.N.; Zambenedetti, E.B.; Leite, J.J.; Valcanaia, E.; Araujo, D.V.; Andrade, J.R.; Avila, W.P.; Caye, S.;Aenhold, D. Controle de fungos na parte aérea do algodão no Mato Grosso in: Anais do III Congresso Brasileiro de Algodão. Campo Grande. EMBRAPA/CNPA-CPAO, UFMS. Campo Grande-MS. 2001 p.543-545
• Fungus can attack plant at any growth stage. Young tissue of plant meristem, leaves, bolls are affected
• Unequal growth of infected foliar blade
causes the leave to crack, forming necrotic stellate spots
• Infect the apical meristem leading to its death, which promotes lateral branching, shortening of internodes and reduction in plant size
Chitarra, L. G. 2014. Doenças do Algodoeiro. SOCIEDADE BRASILEIRA DE FITOPATOLOGIA (SBF). Retrieved from http://www.sbfito.com.br/divulgacao/doencasdoalgodoeiro.pdf
Photo: FMC. Manual of Cotton Diseases
Photo: Oliveira, L.
Photo: FMC. Manual of Cotton Diseases
Photo: IAC, SP.
Photo: Oliveira, L.
Conidia
Symptoms of pink rot roll caused by (Gg). Incubation period is approximately 15 days at 15°C, 11 days at 20°C, 10 days at 25°C, and 9 days at 30°C.
Plant architecture, leaf size and shape, plant stand influence microclimate into the canopy
Asexual phase
Ascospores
Perithecia
Sexual phase
G. gossypii C. gossypii var. cephalosporioides (only asexual)
2nd Inoculum
1st Inoculum
Plant debri, source of overwintered inoculum. Early plowing of fields increases the degradation of plant tissues and reduce the pathogen survival.
Author: Vinicius Garnica
Acervuli
Infested seed, rainfall, wind, overhead irrigation are important in dissemination of propagules.
Damping off at seedling-stage(Gg) and reduced growth associated with excessive branching (Cgc)
At 25°C, weekly rainfall of 60 mm leads to greater periods of leaf wetness (6h up to 32h), which promotes optimum condition for infection
Chemical control of ramulosis in cotton
Photo by APP
• Strobilurins (QoI fungicides) – Act preventing electron transfer at cytochrome bc1 complex • azoxystrobin • pyraclostrobin• trifloxystrobin
• Triazoles (demethylation inhibitors, DMI) – Inhibit C14-demethylase, component of sterol production• Flutriafole• Epoxiconazole• Tebuconaloze
• Benzimidazoles – Inhibition of ß-tubulin assembly in mitosis• carbendazim• thiophanate methyl
• Carboxanilide (SDHI) – Inhibitor of complex II: Succinate dehydrogenase • Carboxin
• Dithiocarbamate – Multi site Action • Thiram
Products registered in Brazil for ramulosis
Vincelli, P. (2002) QoI (Strobilurin) Fungicides: Benefits and Risks. The Plant Health Instructor. DOI: 10.1094/PHI-I-2002-0809-02. Updated, 2012.FRAC. Fungicide Resistance Action Committee. 2015AGROFIT. MAPA
Effect of fungicide treatment on severity of ramulosis
Untreated co
ntrol
Azoxystrobin
Tebuconazole +
thiophanate methyl
trifloxystr
obin +
propiconazole
tebuconazole +
HEC 5725trifl
oxystrobin
tebuconazole +
trifloxystr
obin
Seve
rity
ratin
g
Iamamoto, M.M.; Goes, A.; Cia, E.; Belot, J.L. Controle químico de ramulose no algodoeiro In: Anais do III Congresso Brasileiro de Algodão. Campo Grande. EMBRAPA/CNPA-CPAO, UFMS. Campo Grande-MS. 2001 p. 625-626.
• 3 fungicide applications resulted in 26.8% increase in yield, and 65.8% less incidence of disease
Ampasul, Brazil 2014
Thank you