An apparent decline of fungicide performance for the control of soybean rust in Brazil has been reported but the rate at which it has occurred has not been formally quantified. Control efficacy and yield response to three fungicides applied as single active ingredients (a.i.)—azoxystrobin (AZOX), cyproconazole (CYPR), and tebuconazole (TEBU)—and four applied as mixtures—AZOX+CYPR, picoxystrobin + CYPR, pyraclostrobin + epoxiconazole, and trifloxystrobin + prothioconazole (TRIF+PROT)—were summarized using network meta-analytic models fitted to mean severity and yield data from 250 trials (10-year period). The effect of year was tested on both variables in a meta-regression model. Overall control efficacy ranged from 56 to 84%; the three single-a.i. fungicides performed the poorest (56 to 62%). Yield increase for single-a.i. fungicides was as low as 30% but ranged from 47 to 65% for the premixes. Significant declines in both variables were detected for all fungicides except TRIF+PROT. For TEBU, control efficacy (yield response) declined the most: 78% (18%) to 54% (8%) from 2004–05 to 2013–14. The recent surge of resistant populations of Phakopsora pachyrhizi to both demethylation inhibitor and quinone outside inhibitor fungicides is likely the driving force behind a significant decline after 4 years of fungicide use.

Objetivou-se avaliar a influência de porta-enxertos e ambientes nas características físico-químicas de frutos de maracujazeiros. O experimento foi instalado e conduzido em duas propriedades no município de Terra Nova do Norte, Mato Grosso. Adotou-se o esquema fatorial 2 × 8, no delineamento de blocos casualizados, com quatro repetições, sendo dois ambientes de produção (Ambiente 1 e Ambiente 2) e sete porta-enxertos, além da testemunha. Foram utilizados os portaenxertos dos seguintes genótipos: CPAC M5-H-67, CPAC MJ-H-65, CPAC MJ-45-03, CPAC MJ-H-68, Passiflora nitida (PN), P. alata (PA) e P. edulis (PE), sob a copa da cultivar de maracujazeiro-amarelo, BRS Gigante Amarelo (GA), e essa cultivada em pé franco como testemunha. Após a colheita, retiraram-se, aleatoriamente, dez frutos de cada bloco para a realização das seguintes análises físicas e físico-químicas: massa, comprimento e diâmetro do fruto, espessura da casca, teor de sólidos solúveis totais (SST), acidez total titulável (ATT), relação SST/ATT e teor de vitamina C. O uso dos porta-enxertos e a interação porta-enxertos x ambiente influenciaram as características físicas dos frutos de maracujazeiro. Os ambientes influenciaram as características físico-químicas dos frutos, exceto para a ATT. O ambiente 1 proporcionou frutos de melhor qualidade. No ambiente 2 não houve variação de massa e comprimento de frutos com o uso dos porta-enxertos. Todos os porta-enxertos analisados produziram frutos com características adequadas para consumo in natura ou para industrialização. Palavras-chave: análises qualitativas, fusariose, Passiflora edulis Postharvest quality of yellow passion fruit according to different rootstocks and growing environments AbstractThe objective of this study was to evaluate the influence of rootstocks on passion fruit physicochemical characteristics. The experiment was conducted in two properties in Terra Nova do Norte municipality, Mato Grosso State, Brazil. The experiment was conducted in a 2×8 factorial, in a completely randomized block design with four repetitions, being two growing environments (Environment 1 and Environment 2) and seven rootstocks with one control. The rootstocks used were: CPAC M5-H-67, H-CPAC MJ-65, CPAC MJ-45-03, CPAC MJ-H-68, Passiflora nitida (PN), P. alata (PA) and P. edulis (PE), under the canopy of a yellow passion fruit, BRS Gigante Amarelo cultivar. The same cultivar without rootstock was used as a control. The fruits were randomly harvest from each block. The following physical, physicochemical and chemical analysis were performed: weight, fruit length and diameter of the fruit, skin thickness, total soluble solids content (TSS), total acidity (TA), TSS/TA and vitamin C content. The use of rootstocks and rootstocks x environment interaction influenced the passion fruit physical characteristics. The environments influenced fruit quality, except for total acidity content. Environment 1 resulted in best fruit quality. For the Environment 2 no weight and length variation caused by rootstocks was observed. All an...

Considering the lack of information in literature about the p a t h o ge n i c va ri a b i li t y of B ra zi li a n i s o la t es of X a n t h o m o n a s campestris pv. campestris, a study was carried out to determine t h e p a t h o ge n i c s p e c i f i c i t y o f 3 3 i s o l a t e s o f t h i s b a c t e r i u m originated from several regions of Brazil and overseas to eight d i f feren t B r a s s i c a s p ec i e s , t h rou gh i n oc u la t i on b y m e a n s of injection of the bacterial suspension in leaves. From these isolates, 12 were obtain ed from collard greens ( Bra ssic a ol erac ea var. acephala ), nine from cabbage (B. oleracea var. capitata ), five

The aim of the study was to identify sources of resistance of Passiflora rootstocks to Fusarium sp. in two experimental areas with histories of disease foci in Mato Grosso state, Brazil. The experiment was carried out from June 2012 to December 2015 and was of randomized block design with eight treatments in which susceptible cultivar P. edulis was grafted onto hybrids CPAC MJ-H-87, CPAC MJ-H-76, CPAC MJ-H-86 and CPAC MJ-H-88, the commercial cultivar and native P. edulis, P. nitida and P. alata. Mortality rates of grafted plants were evaluated up to 640 days after transplantation. All Fusarium sp. isolates were identified as F. oxysporum f. sp. passiflorae. Plant mortality occurred earlier in the clay area than in the area with sandy clay loam. Grafted plants involving P. edulis as rootstocks were highly susceptible to Fusarium sp. with overall mortality rates above 56.25% considering both soil types, while plants with CPAC MJ-H-76 or native P. nitida rootstocks were more resistant with mortality rates below 12.5%. Grafted plants with CPAC MJ-H-86 as rootstock were highly resistant in clay soil but highly susceptible in soil with high proportion of sand. Only grafted plants involving CPAC MJ-H-76 as rootstock showed moderate resistance.

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