Andréa Chaves

Eficiência e atividade enzimática elicitada por metil jasmonato e silicato de potássio em cana-de-açúcar parasitada por Meloidogyne incognita

ABSTRACT The present study had as objective to evaluate methyl jasmonateand potassium silicate effect on Meloidogyne incognita parasitism insugarcane ( Saccharum sp.) variety RB863129 and peroxidase and -1,3-glucanase activity elicited, under greenhouse. The effect of Methyljasmonate and potassium silicate did not affect shoot biomass. Methyljasmonate and potassium silicate significantly decreased eggs number Guimaraes, L.M.P., Pedrosa, E.M.R., Coelho, R.S.B., Couto, E.F., Maranhao, S.R.V.L. & Chaves, A. Efficiency and enzymatic activity elicited bymethyl jasmonate and potassium silicate on sugarcane under Meloidogyne incognita parasitism. Summa Phytopathologica, v.36, n.1, p.11-15, 2010. Keywords: root-knot nematode, Saccharum sp., peroxidase, -1,3-glucanase, resistance induction Palavras-chave adicionais: Nematoide das galhas, Saccharum sp . , peroxidase, -1,3-glucanase, inducao de resistencia RESUMO O presente estudo teve como objetivo avaliar o efeito de metiljasmonato e silicato de potassio sobre o parasitismo de

Resistance Induction for Meloidogyne incognita in Sugarcane through Mineral Organic Fertilizers

The effects of Coda Radimax (CR), Coda Humus-PK (CH) and Coda Vit (CV) on the induction of resistance for Meloidogyne incognita in sugarcane (Saccharum sp.) varieties (RB92579, RB863129, RB867515) through nematode reproduction, plant development and root anatomy analysis, emphasizing the differences of the lignin deposition, and cortex-vascular cylinder proportions were investigated. In 90 days after inoculation with eggs of M. incognita, CR reduced the number of eggs per root system in all the sugarcane varieties; CH and CV reduced eggs density in RB867515; CR increased stalk number in RB92579 and fresh weight of shoots in RB863129 and RB92579; CH increased plant height in RB92579 and fresh weight of shoots in RB92579 and RB867515, CV affected fresh weigh of shoots and roots of RB863129. All the tested compounds did not affect stalk diameter, number and dry weight of shoots. Cross-sections of roots showed no anatomical changes in the M. incognita inoculated tissues.

Efeito de terbufos em soqueira sobre fitonematóides ectoparasitos de cana-de-açúcar

Due to the usually high population levels of ectoparasitic nematodes associated with sugarcane (Saccharum spp.) Northeastern Brazil, the effect of the systemic nematicide Terbufos (Counter 50G) was studied, on first ratoon, in soil naturally infested with Helicotylenchus dihystera, Criconemella ornata and Paratrichodorus minor. The experimental design consisted of completely randomized blocks with treatments factorially arranged in 2x3x5 (two harvest periods x three nematicide doses x five sugarcane varieties), with five replicates. Nematicide doses consisted of 3 kg a.i./ha, applied at planting and immediately after first cutting, 4 kg a.i./ha, applied at planting and control, 0 kg a.i./ha, distributed into 2.0 m x 2.0 m microplots. Evaluations based on nematode population densities were carried out on five varieties, CB45-3, RB813804, SP78-4764, SP79-1011 e SP 70-1143, at plant and first ratoon harvest. There was no interaction among nematicide, variety and harvest time. Results showed nematicide doses and sugarcane varieties did not affect significantly nematode population levels. However, in contrast to H. dihystera, population densities of C. ornata and P. minor were significantly lower at ratoon than plant harvest.

Presence of orange rust on sugarcane in the state of Pernambuco, Brazil.

Sugarcane leaf rust symptoms were observed on seven month-old plants in March 2012 at Santa Teresa Farm, north coast of Pernambuco, Brazil. Plants were identified as a genotype coded as RBUFRPE0032 developed by the Sugarcane Breeding Program of Universidade Federal Rural de Pernambuco (UFRPE/EECAC). Evaluations under field conditions showed characteristic leaf rust symptoms and high severity. Analysis of symptomatic leaves under the optical microscope at the Plant Pathology Laboratory of UFRPE/EECAC confirmed the presence of fungal urediniospores showing specific characteristics of the fungus. Molecular evaluation by real-time PCR yielded positive results for Puccinia kuenhii. This is the first report of sugarcane leaf rust in Pernambuco. Although the disease has been reported in other Brazilian states, producers and researchers are worried since the behavior of promising commercial varieties and clones from breeding programs directed at the soil and climatic conditions of the state is unknown. The Ministry of Agriculture in Pernambuco was officially informed for notification purposes.