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The incidence–severity relationship for cashew gummosis, caused by Lasiodiplodia theobromae, was studied to determine the feasibility of using disease incidence to estimate indirectly disease severity in order to establish the potential damage caused by this disease in semiarid north‐eastern Brazil. Epidemics were monitored in two cashew orchards, from 1995 to 1998 in an experimental field composed of 28 dwarf clones, and from 2000 to 2002 in a commercial orchard of a single clone. The two sites were located 10 km from each other. Logarithmic transformation achieved the best linear adjustment of incidence and severity data as determined by coefficients of determination for place, age and pooled data. A very high correlation between incidence and severity was found in both fields, with different disease pressures, different cashew genotypes, different ages and at several epidemic stages. Thus, the easily assessed gummosis incidence could be used to estimate gummosis severity levels.

-The objective of this experiment was to characterize the dry matter production of vegetative components (stalk, leaf, husk, and cob) and reproductive components (grain) of the corn plant according to planting time and the grain maturity stage. Eight corn hybrids with different agronomic characteristics were used to carry out the experiments. Two experiments were performed with planting undertaken on 11/11/2007 and 12/12/2007 under a conventional tillage system. The eight corn cultivars were harvested at three grain maturity stages, half milk line, three quarters milk line and black layer. An 8 × 3 factorial (eight hybrids and the three cutting times) randomized blocks design was used, with three replications. Individual analysis of variance was performed for each experiment. Then joint analysis of variance was performed involving the two planting times. The means were grouped and the hybrids used as replications to characterize the components. Delay in planting significantly reduced the dry matter productivity of the whole plant; however, it did not reduce its degradability. The greatest dry matter productivity obtained was that of grain, followed by stalk, leaf, husk and cob. The vegetative components, leaves and husk, lose quality with delay in planting. The leaf is the vegetative component of highest quality, while the cob is the worst. Delay in planting increases the neutral detergent fiber content of the stalk, husk and cob.

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RESUMOO objetivo desse trabalho foi avaliar o nível de resistência de 12 híbridos comerciais de milho à cercosporiose, causada por Cercospora zeae-maydis, e à Mancha Branca, causada por Pantoea ananatis e comparar a eficiência das estimativas da área abaixo da curva de progresso das doenças e da estabilidade fenotípica, na avaliação da resistência a esses patógenos. Foram conduzidos três experimentos, no ano agrícola de 2007/2008, em três locais. Utilizou-se o delineamento em blocos ao acaso com três repetições. Foram realizadas cinco avaliações da severidade das doenças, em intervalos de sete dias, a partir dos 80 dias da emergência, por meio de uma escala de notas variando de 1 (altamente resistente) a 9 (altamente suscetível). Foram estimadas a área abaixo da curva de progresso da doença (AACPD) e o coeficiente de regressão linear (b 1 ) entre a variável independente época de avaliação (x) e a variável dependente severidade da doença (y) e o coeficiente de determinação (R 2 ). Observou-se que, ambas as metodologias utilizadas mostraram-se eficientes na discriminação do nível de resistência dos híbridos avaliados à Cercosporiose e à Mancha Branca, permitindo a classificação de modo semelhante. Os híbridos mais resistentes às duas doenças foram o AG7088, AG7010 e 2B707 e os mais suscetíveis o 30F44, 30F53 e AG8021. Os híbridos 30K64, DKB177, DKB390 e Impacto apresentaram comportamento variável em função dos locais de avaliação. Palavras-chave: Cercospora zeae-maydis, Pantoea ananatis, estabilidade fenotípica, doenças fúngicas. ABSTRACT Reaction of commercial corn hybrids and comparison of methods for evaluation of maize White Spot and Gray Leaf SpotWith the objective of evaluating the resistance level of commercial corn hybrids and comparing the efficiency of the estimates of the area under the disease progress curve (AUDPC) and that of the phenotypical stability parameters in the evaluation of resistance maize white spot and gray leaf spot, three experiments were carried out in the agricultural year of 2007/2008 in three environments. Twelve commercial maize hybrids were used, in a randomized block experimental design with three replications. Five evaluations of disease severity (maize white spot and gray leaf spot) based on visual symptoms were performed at seven-day intervals from the 80 th day after maize emergence, ranging from 1 (highly resistant) to 9 (highly susceptible). The area under the disease progress curve (AUDPC) was estimated, as were the phenotypical stability parameters, i.e., the linear regression coefficient (b i ) between the independent variable evaluation time (x), and the dependent variable, disease severity (y) and the determination coefficient (R 2 ). It was found that in the case of maize white spot and maize gray leaf spot, both methodologies used proved to be effective in the discrimination of the resistance level of the hybrids, enabling them to be ranked in a similar way. The most resistant hybrids to maize white spot and maize gray leaf spot were AG7088, AG 7010 and 2B707, and t...

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Post-harvest basal rot of coconut fruits in the State of Ceará, BrazilA new post-harvest disease of coconut (Cocos nucifera) was recently detected in fruits exported to European countries. The main symptoms are the blacking and cracking of basal parts of the fruits. Water oozing may occurs as the infection progresses. The fungus