Lílian Margarete Paes Guimarães

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.

Soursop, a new host of Rotylenchulus reniformis

RESUMO Gravioleira, uma nova hospedeira de Rotylenchulus reniformis Este trabalho reporta o primeiro assinalamento do parasitismo de Rotylenchulus reniformis em gravioleira (Annona muricata) resultando numa condição de doença na hospedeira. A identificação específica do nematóide foi feita por micrometria de fêmeas imaturas, associada à presença de machos, de acordo com Lehman & Inserra. A síndrome foi considerada severa, afetando o desenvolvimento do hospedeiro.

Atypical Pratylenchus coffeae disease observed in the state of Rio Grande do Norte.

ABSTRACT Atypical Pratylenchus coffeae disease observed in the State ofRio Grande do Norte This paper reports the unique ocorrence of the lesionnematode Pratylenchus coffeae on sweet corn ( Zea mays ) cv. Elisain Mossoro county, state of Rio Grande do Norte. The nematodestrongly inhibited root development by forming large amout of locallesions. The disease now reported was severe inducing high fieldlosses. This is the first report on this patossystem in Brazil. Os nematoides das lesoes, representados por especiesdo genero Pratylenchus Graham, sao, de modo inconteste,serios problemas da agricultura mundial, incluindo-se, comdestaque, o nordeste brasileiro. O abacaxi [ Annona comosus (L.) Merr.], amendoim ( Arachis hypogaea L.), cana-de-acucar( Saccharum sp.), gravioleira ( Annona muricata L.), inhame( Dioscorea cayennensis Lam.) e milho ( Zea mays L.), saoexemplos de culturas com registro de alta suscetibilidade nestaregiao e as especies P. brachyurus (Godfrey) Filipjev &Stekhoven,

A rare syndrome of corn smut

The common smut of corn (Zea mays L.) caused by the Basidiomycete Ustylago maydis (DC.) Cda. occurs worldwide wherever maize is grown in warm, moderate dry areas. In the northeast of Brazil, this disease is endemic and never reaches levels of incidence higher than 1% in large fields. Usually farmers do not react strongly against this disease that causes corn ears to swell into a grey fungal mass, often regarded in Mexico and United States as a delicacy. In fact, corn ears with smut have a subtle but pleasant flavour and are selling as a premium to numerous restaurants. For this reason, farms are now trying to grow the stuff intentionally. According to old references this disease has been of high economic importance for a long time. For instance, Chester (Nature and Prevention of Plant Diseases. 3nd ed. New York. Mc Graw Hill Book Company. 1950) stated that the annual average loss for the United States at that time was around 3 to 5%, or 50 to 80 million bushels, ranging up to 10% in some states. Today with resistant varieties, losses seldom exceed 2% in large areas. Damage includes yield reduction through sterility, destruction of the ears, reduction of the amount of fodder and lowering of carbohydrate content. Smutted stalks yield about one third less grain than healthy ones. The fungus causing common smut can attack any above ground organ of the corn plant: stalk, prop root, leaf, tassel, husk or, most commonly, ears (Figure 1a). The disease is readilly identified by boils, also called galls, which are often larger on ears and stalks and much smaller on leaves or tassels. This structure is full of a black mass of chlamydospores, the teliospores. This paper reports an occurrence of smut on the upper part of the stalk of a sweet corn cultivar (Figure 1b, c). The disease was affecting two commercial hybrid plants, in Camaragibe, State of Pernambuco, Brazil. After stalk infection, a small gall was seen to protude from inside of the plant tissue, which was at first covered with a greenish-white membrane (Figure 1b).When the gall reached maturity it measured 18 cm in diameter, with blades dividing the inside into sections full of black teliospores. At this stage, the gall was covered by a silverwhite membrane. After it ruptured, the gall released a large dustlike cloud of black teliospores. In BDA medium, at 30 oC, the teliospores produced the normal four-celled promycelium, the FIG. 1 a) Common syndrome of corn (Zea mays) smut; b) Inicial stage of protuded gall; c) Late stage of the gall; d) Typical Ustilago maydis teliospores (Bar = 1 μm)