Sooty blotch and flyspeck (SBFS) is a late-season disease of apple and pear fruit that cosmetically damages the cuticle, resulting in produce that is unacceptable to consumers. Previous studies reported that four species of fungi comprise the SBFS complex. We examined fungal morphology and the internal transcriber spacer (ITS) and large subunit (LSU) regions of rDNA of 422 fungal isolates within the SBFS complex from nine orchards in four Midwestern states (USA) and compared them to previously identified species. We used LSU sequences to phylogenetically place the isolates at the order or genus level and then used ITS sequences to identify lineages that could be species. We used mycelial and conidial morphology on apple and in culture to delimit putative species. Thirty putative species found among the Midwest samples were shown to cause SBFS lesions on apple fruit in inoculation field trials. Among them Peltaster fructicola and Zygophiala jamaicensis have been associated previously with SBFS in North Carolina. The LSU analyses inferred that all 30 SBFS fungi from Midwestern orchards were Dothideomycetes; one putative species was within the Pleosporales, 27 were within Dothideales, and two putative species could not be placed at the ordinal level. The LSU sequences of 17 Dothideales species clustered with LSU sequences of known species of Mycosphaerella.

Sooty blotch and flyspeck (SBFS) is a late-season disease of apple and pear fruit that cosmetically damages the cuticle, resulting in produce that is unacceptable to consumers. Previous studies reported that four species of fungi comprise the SBFS complex. We examined fungal morphology and the internal transcriber spacer (ITS) and large subunit (LSU) regions of rDNA of 422 fungal isolates within the SBFS complex from nine orchards in four Midwestern states (USA) and compared them to previously identified species. We used LSU sequences to phylogenetically place the isolates at the order or genus level and then used ITS sequences to identify lineages that could be species. We used mycelial and conidial morphology on apple and in culture to delimit putative species. Thirty putative species found among the Midwest samples were shown to cause SBFS lesions on apple fruit in inoculation field trials. Among them Peltaster fructicola and Zygophiala jamaicensis have been associated previously with SBFS in North Carolina. The LSU analyses inferred that all 30 SBFS fungi from Midwestern orchards were Dothideomycetes; one putative species was within the Pleosporales, 27 were within Dothideales, and two putative species could not be placed at the ordinal level. The LSU sequences of 17 Dothideales species clustered with LSU sequences of known species of Mycosphaerella.

The spatial variability of leaf wetness duration (LWD) was evaluated in four different height-structure crop canopies: apple, coffee, maize, and grape. LWD measurements were made using painted flat plate, printed-circuit wetness sensors deployed in different positions above and inside the crops, with inclination angles ranging from 30 to 45 degrees. For apple trees, the sensors were installed in 12 east-west positions: 4 at each of the top (3.3 m), middle (2.1 m), and bottom (1.1 m) levels. For young coffee plants (80 cm tall), four sensors were installed close to the leaves at heights of 20, 40, 60, and 80 cm. For the maize and grape crops, LWD sensors were installed in two positions, one just below the canopy top and another inside the canopy. Adjacent to each experiment, LWD was measured above nearby mowed turfgrass with the same kind of flat plate sensor, deployed at 30 cm and between 30 and 45 degrees. We found average LWD varied by canopy position for apple and maize (P<0.05). In these cases, LWD was longer at the top, particularly when dew was the source of wetness. For grapes, cultivated in a hedgerow system and for young coffee plants, average LWD did not differ between the top and inside the canopy. The comparison by geometric mean regression analysis between crop and turfgrass LWD measurements showed that sensors at 30 cm over turfgrass provided quite accurate estimates of LWD at the top of the crops, despite large differences in crop height and structure, but poorer estimates for wetness within leaf canopies.

Sooty blotch and flyspeck (SBFS) fungi colonize the surface wax layer of the fruit of apple, pear, persimmon, banana, orange, papaya, and several other cultivated tree and vine crops. In addition to colonizing cultivated fruit crops, SBFS fungi also grow on the surfaces of stems, twigs, leaves, and fruit of a wide range of wild plants. The disease occurs worldwide in regions with moist growing seasons. SBFS is regarded as a serious disease by fruit growers and plant pathologists because it can cause substantial economic damage. The smudges and stipples of SBFS often result in downgrading of fruit from premium fresh-market grade to processing use. This review describes the major shifts that have occurred during the past decade in understanding the genetic diversity of the SBFS complex, clarifying its biogeography and environmental biology, and developing improved management strategies.

Disease-warning systems are decision support tools designed to help growers determine when to apply control measures to suppress crop diseases. Weather data are nearly ubiquitous inputs to warning systems. This contribution reviews ways in which weather data are gathered for use as inputs to disease-warning systems, and the associated logistical challenges. Grower-operated weather monitoring is contrasted with obtaining data from networks of weather stations, and the advantages and disadvantages of measuring vs. estimating weather data are discussed. Special emphasis is given to leaf wetness duration (LWD), not only because LWD data are inputs to many disease-warning systems but also because accurate data are uniquely challenging to obtain. It is concluded that there is no single "best" method to acquire weather data for use in disease-warning systems; instead, local, regional, and national circumstances are likely to influence which strategy is most successful. Key words: integrated pest management, site-specific weather data, disease forecasting, disease prediction, sustainable agriculture OBTENÇÃO DE DADOS METEOROLÓGICOS PARA SISTEMAS DE ALERTA FITOSSANITÁRIO: O CASO DA DURAÇÃO DO PERÍODO DE MOLHAMENTO FOLIARRESUMO: Os sistemas de alerta fitossanitário são ferramentas de suporte à decisão desenvolvidos para ajudar os agricultures a determinar o melhor momento da aplicação das medidas de controle para combater as doenças de plantas. As variáveis meteorológicas são dados de entrada quase que obrigatórios desses sistemas. Este trabalho apresenta uma revisão sobre os meios pelos quais as variáveis meteorológicas são coletadas para serem usadas como dados de entrada em sistemas de alerta fitossanitário e sobre os desafios associados à logística de obtenção desses dados. Essa revisão compara o monitoramento meteorológico ao nível do produtor, nas propriedades agrícolas, com aquele feito ao nível de redes de estações meteorológicas, assim como discute as vantagens e desvantagens entre medir e estimar tais variáveis meteorológicas. Especial ênfase é dada à duração do período de molhamento foliar (DPM), não somente pela sua importância como dado de entrada em diversos sistemas de alerta fitossanitário, mas também pelo desafio de se obter dados acurados dessa variável. Pode-se concluir, após ampla discussão do assunto, que não há um método único e melhor para se obter os dados meteorológicos para uso em sistemas de alerta fitossanitário; por outro lado, as circunstâncias a nível local, regional e nacional provavelmente influenciam a estratégia de maior sucesso. Palavras chave: manejo integrado de doenças, dados meteorológicos específicos do local, previsão de doenças, estimativa de doenças, agricultura sustentável