Avaliou-se o comportamento de trinta e seis genótipos de soja em relação à incidência da queima-do-broto em condições de campo, no Centro Experimental de Campinas (IAC), no ano agrícola 1985/86. A infecção variou de 13 a 92%, destacando-se PI 227687 (13%), IAC 73-228 (25%), IAC 80-1177 (36%), IAC 80-1191 e IAC 84-20-1 (38%) e PI 274453 (40%) com os menores índices da doença. Os cinco genótipos menos infectados, mais a linhagem IAC 79-1823 e os cultivares IAC 9, IAC 10, IAC 12, Santa Rosa, Cristalina e IAC Foscarin-31, inoculados mecanicamente em casa de vegetação com diferentes isolados do vírus, não mostraram nível de resistência semelhante ao observado em campo; nesse teste, a infecção variou de 45 a 90%, tendo o melhor tratamento do experimento de campo (PI 227687) apresentado 90% de infecção. Há indicação, portanto, que a menor infecção observada nos genótipos no experimento de exposição natural seja resistência de campo, relacionada com a interação planta-tripes vetor.

Brazilian bud blight, a soybean disease caused by the tobacco streak virus, is prevalent in a few areas in the States of Paraná and São Paulo. Although the virus is seed-transmitted, outbreaks of the disease are related to the presence of virus in donor plants in the weed vegetation and not to seed sources. Species of Frankliniella act as vectors. Thirty six soybean genotypes, about half of them known to have varying degrees of resistance to insects, were evaluated when exposed to natural infection by bud blight in five replicated plots sown in an area where medium to severe outbreaks of the virus had occurred in previous years. Incidence of bud blight was high in the experiment and reached 90% infection for some of the genotypes. Best genotypes for resistance to bud blight were PI 227687 (13% infection), IAC 73-228 (25%), IAC 80-1177 (36%), IAC 80-1191 and IAC 84-20-1 (both 38%), and PI 274453 (40%). The best five most resistant genotypes mentioned above plus seven others were also screened by mechanical inoculation of greenhouse plants with five isolates of the soybean bud blight virus. The results were not parallel to those read in the field exposure test. Thus, the response of PI 227687, IAC 73-228 and probably those of some of the other best genotypes are not considered the result of plant resistance to the virus, but rather as field resistance related to the interaction plant/thrips vector.

A anomalia do cultivar de videira Niagara Rosada, caracterizada por sintomas de clorose nas folhas, chocolate das bagas e cachos malformados, não é de natureza virótica, de acordo com resultados de testes de transmissão e de perpetuação. Essa anomalia, presente em áreas definidas de alguns vinhedos de Indaiatuba e Jundiaí (SP), está associada à deficiência nutricional de boro. O teor médio de boro em amostras de plantas afetadas de 'Niagara Rosada' (18 ppm no limbo e 7 ppm nos frutos) foi menor do que nas de plantas normais (24 ppm no limbo e 10 ppm nos frutos) das mesmas plantaçoes; um material coletado de um vinhedo bastante afetado mostrou 13 e 1 ppm respectivamente no limbo e nos frutos de plantas deficientes contra 20 e 6 ppm nos de plantas sem sintomas. Amostras de três vinhedos vizinhos sem essa anomalia apresentaram um teor médio de 35 ppm no limbo. As do porta-enxerto 'Traviú' com clorose e sem clorose mostraram 16 ppm e 43 ppm de boro respectivamente. A aplicação de bórax, nas doses de 5, 10 e 20g por planta, 1ogo após a poda de inverno, ou pulverização de ácido bórico nas concentraçoes de 0,3% e 0,6% sobre a folhagem, durante o início do florescimento e durante a fase de uva chumbinho, permitiram controlar a anomalia nas condições de campo. Foi notada resposta favorável por um ciclo vegetativo, pelo menos, indicando controle por efeito residual de uma aplicação.

The 'pink Niagara' grape (V. labrusca L. x V. vinifera L.) anomaly characterized by leaf chlorosis and "chocolate" (internal browning) of the young fruit, at first thought to be a virus disease, has been found to be a result of boron deficiency. The anomaly was first recorded in 1974. It occurs in patches in vineyards of Indaiatuba and Jundiaí, two grape-growing counties of the State of São Paulo, Brazil. Affected plants show yellowing between the primary and secondary veins of the upper leaves and malformed clusters, with normal-sized berries and small ones. Some small fruits are slightly elongated and show dark areas on the skin; many have dark brown pulp, easily visible when they are still green. Severely affected plants become stunted. Chemical analysis showed a lower boron content in the affected plants (18 ppm in the leaf blades and 7 ppm in the fruit) than in normal ones (24 ppm in the leaf blades and 10 ppm in the fruit). Leaf samples from three nearby vineyards without the anomaly presented a boron content of 35 ppm. Leaf blades from abnormal and normal 'Traviú' rootstocks (V. riparia Michaux. x V. rupestris Scheele x V. cordifolia Michaux., '106-8') had 16 ppm and 43 ppm B, respectively. An efficient control of the anomaly was got with borax, applied after prunning to affected plants at the rates of 5, 10 and 20 g per plant, or with boric acid at the concentrations of 0.3 and 0.6%a sprayed at flowering and when the fruits were small. There was a residual effect of the treatment on the anomaly for at least one more season.