Strong population subdivision according to the host was revealed in a study designed to assess the genetic variability of Alternaria solani on potato (Solanum tuberosum) and tomato (S. lycopersicum) in Brazil (Lourenço Jr. et al., 2009).We hypothesised that more than one species cause early blight disease on these hosts. We analysed 19 isolates obtained from potato and nine from tomato, sampled from 2005 to 2008 from seven geographic regions. Ex-type and authentic isolates of A. tomatophila , and a representative isolate of were used for comparison (Simmons, 2000). Based on morphological characteristics all isolates from tomato were identified as A. tomatophila and those from potato as A. grandis (Simmons, 2007) (Fig. 1; Table 1).A. solani was not detected in the samples. A preliminary report has been previously published (Rodrigues & Mizubuti, 2009).The pathogenicity of three isolates from tomato and five from potato were tested on susceptible plants in cross inoculation assays. Two drops of a 10 4 conidia/ml suspension were placed on five leaflets in each plant (six plants/isolate). The lesion diameter (mm) was determined using a digital caliper and the formula of the area of a circle was used to estimate the lesion area (LA) four days after inoculation. On potato, the mean LA for A. grandis was 464.1 (SD = 53.0) compared to 345.9 (SD = 48.0) for A. tomatophila. On tomato, the mean LA for A. tomatophila was 64.9 (SD = 5.2) compared to 33.8 (SD = 8.1) for A. grandis. Although larger lesions were formed when A. grandis and A. tomatophila were inoculated on their host of origin, there was no statistical difference between species on a particular host. The isolates were recovered from the lesions to fulfil Koch's Postulates. Additionally, reconstruction of the phylogeny was used to investigate the relationships among the species. The major allergen Alt a1 and glyceraldehyde-3-phosphate (Gpd) genes data set were analysed. The Brazilian isolates from tomato clustered with the ex-type A.tomatophila isolate with strong support from parsimony (MP) and neighbour-joining (NJ) analyses. The A. grandis population clustered most closely with the ex-type isolate of A. grandis in a clade also including A. solani (Fig. 2). Alternaria tomatophila has been recorded to cause early blight on tomato in the United States, Australia, New Zealand, and Venezuela (Simmons, 2000).In Brazil, A. solani has been reported as the causal agent of early blight (Lourenço Jr. et al., 2009). We report here that at least two additional species are widely distributed on tomato and potato fields in Brazil.

No abstract

Trichoderma spp. is a fungus with nematode control potential; however, its potential to control the root lesion nematode Pratylenchus brachyurus remains poorly studied.Thus, the aim of this study was to select Trichoderma spp. isolates and assess their ability to control P. brachyurus in soybean crops. Different experiments were conducted aiming at selecting isolates, assessing whether they were able to reduce nematode penetration in plants or cause mortality in vitro, and whether they were able to induce resistance in soybean, as well as at studying the possibility of using the selected isolates associated with resistance inducers (acibenzolar-S-methyl, Ecolife™ and AgroMos™). The selection experiment found three isolates showing satisfactory results, namely GF422, GF425 and GF427; the GF362 isolate was assessed in the subsequent experiments. These four isolates reduced P. brachyurus penetration in soybean roots and promoted nematode mortality in vitro. Increased total protein and catalase activity were recorded, mainly in the 72-hr assessments. Overall, the protein production was different between isolates. The best results were found in the combination between the GF362 isolate and the three resistance inducers, between GF427 and Ecolife™, between GF427 and AgroMos™ and between GF422 and Ecolife™. K E Y W O R D Sbiological control, Glycine max, nematophagous fungi, resistance induction, root lesion nematode

- BGH-2081, BGH-2034, BGH-700, BGH-2057, BGH-2035, BGH-2054, BGH-2018, BGH-2065, BGH-2008, and BGH-2032 had a lower mean AUDPC than the controls and are therefore indicated for future breeding programs.

Growth promoting rhizobacteria may increase the yield of some crops. Several microbial products that stimulate plant growth have been marketed. Therefore, the objective of this study was to evaluate the effect of bacteria from Bacillus genera on the production of commercial carrot roots (Daucus carota L.) in field conditions. The following isolates: SF 264 (Bacillus spp.), SF 268 (Bacillus spp.) and commercial formulations based on SF 202 (Rizos®, B. subtilis), SF 266 (Quartz®, B. methylotrophicus) and SF 267 (Onix®, B. methylotrophicus) were evaluated in four experiments conducted in commercial fields of carrot production in the municipality of Rio Paranaíba, Minas Gerais-Brazil. Each plot was 6 m long and 1.75 m wide (10.5 m 2) including four double rows. An additional treatment containing only water was the control treatment. The experiment was designed as randomized blocks with five replications. The products Rizos ® , Quartz ® and Onix ® containing Bacillus spp. increased the production of commercial carrots roots of all cultivars and sites. The SF 268 and SF 264 isolates were efficient only in two and three experiments, respectively.