Pepper Phytophthora blight (PPB), caused by Phytophthora capsici, is an important disease of pepper in China. The extensive application of metalaxyl has resulted in widespread resistance to this fungicide in field. This study has evaluated the activities of several fungicides against the mycelial growth and sporangium germination of metalaxyl-sensitive and metalaxyl-resistant P. capsici isolates by determination of EC 50 values. The results showed that the novel carboxylic acid amide (CAA) fungicide mandipropamid exhibited excellent inhibitory activity against PPB both in vitro and in vivo, with averagely EC 50 values of 0.075 and 0.004 lg/ml in mycelial growth and sporangium germination, respectively, and over 88% efficacy in controlling PPB. The other three CAA fungicides also provided over 70% efficacy in controlling PPB. The mycelial growth was less sensitive to quinone outside inhibitor (QoI) fungicides azoxystrobin and trifloxystrobin than that of sporangium germination in P. capsici isolates. However, azoxystrobin and trifloxystrobin provided over 80% efficacy in controlling PPB. It was noted that propamocarb and cymoxanil did not exhibit activity against the mycelial growth or sporangium germination of P. capsici isolates in the in vitro tests, with over 70% efficacy in controlling PPB. The new fungicide mixture 62.5 g/l fluopicolide + 625 g/l propamocarb (trade name infinito, 687.5 g/l suspension concentrate (SC)) produced over 88% efficacy in controlling PPB caused by both metalaxyl-sensitive and metalaxylresistant isolates. The data of this study also proved that there was obviously no cross-resistance between metalaxyl and the other tested fungicides. Therefore, these fungicides should be good alternatives to metalaxyl for the control of PPB and management of metalaxyl resistance. = 0.05; 1The isolates HN3-Mt r and YX32-Mt r , which were resistant to metalaxyl were generated from the isolates HN3 and YX32, respectively; 2 EC 50 , 50% effective concentration; 3 Infinito (687.5 g/l SC), trade name of the new fungicide mixture 62.5 g/l fluopicolide

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Meloidogyne javanica is one of the most widespread and economically important nematodes in many countries, including China. In this study, a recombinase polymerase amplification (RPA) assay was evaluated for the detection of M. javanica based on the sequences of a sequence-characterized amplified regions marker gene segment. The RPA assay specifically detected M. javanica from individual juvenile or adult female, M. javanica-induced galls, and nematodes in the soil samples. The detection limit of M. javanica RPA assay was 1 pg of purified genomic DNA, 0.01 adult female, or 0.1 second-stage juvenile, which was 10 times more sensitive than conventional PCR assay. Furthermore, combined with lateral flow dipstick (LFD), a visual detection method of LFD-RPA assay was developed, which is suitable for onsite surveys and routine diagnostics. Results indicate that the RPA assay is rapid, sensitive, and reliable for detection and molecular identification of M. javanica.

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