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Background: Studies carried out with novel 13 strains of Trichoderma, isolated from mangrove sediments (PE, Brazil) using morphophysiological and molecular characterization, followed evaluation of biocontrol using Fusarium strains isolated from Caatinga soil (PE, Brazil). Trichoderma strains were characterized by polyphasic taxonomic approach, and the extracted DNA was amplified with primers ITS 1 and 4, and sequenced. The biocontrol evaluation was conducted at 24 and 48 h of growth intervals by Tukey test, with a significance of 5%. Antibiosis tests were assessed in vitro by dual plate and partition plate techniques against Fusarium strains. Results: Trichoderma molecular identification, sequences of 500 bp were amplified, deposited into GenBank, and used for phylogenetic analyses. The strains were identified as T. asperellum (10), as T. harzianum (2) and one as T. longibrachiatum. Growth rate presented an average of 0.1207 cm h −1 for Trichoderma and lower growth rate of 0.031 cm h −1 for Fusarium spp., respectively. Antibiosis tests presented the best antagonist level of efficiency for T. asperellum UCP 0149 against F. solani UCP 1395 (82.2%) and F. solani UCP 1075 (70.0%), followed by T. asperellum UCP 0319 against F. solani UCP1083 (73.4%) and T. asperellum UCP 0168 against F. solani UCP1098 (71.5%), respectively. Conclusions: The data obtained in this study as tool for identification of novel Trichoderma strains serve as basis for development of several sustainable use for biotechnological processes. Those Trichoderma strains found promising for the management antagonistic potential and interaction could aid the conduct of biotechnological biocontrol of contaminants, and improve environmental conditions for the health of plants.

Filamentous fungi able to hydrolyse inulin have been isolated from the rhizosphere of plants whose roots contain this polysaccharide. This study reports results concerning the isolation and identification of filamentous fungi from the soil used for sunflower cultivation and from the sunflower rhizosphere cultivated in field and in greenhouse. Fungi were evaluated according to their capacity to hydrolyse inulin and the variation in the diversity of these fungi during the plant's life cycle was also accessed. Forty-nine species of filamentous fungi were isolated. Penicillium and Aspergillus were the genera that presented higher number of species, nine and seven, respectively. At the end of the sunflower life cycle, cultivated both in field and in the greenhouse, a lower numbers of species were isolated. One hundred and fifty nine strains of filamentous fungi were isolated from soil and from the sunflower rhizosphere; from these, 79 (49.7%) were able to hydrolyse inulin. There was not significant difference in the proportion of species able to hydrolyse this polysaccharide during the sunflower's life cycle, in plants cultivated in field or in greenhouse. Although the sunflower's rhizosphere is a source of filamentous fungi able to hydrolyse inulin, that might be used in biotechnological processes. This system does not present a higher density of such microorganisms. Species of Aspergillus, Chaetomium, Cunninghamella, Emericela, Eupenicillium, Fusarium, Myrothecium, Neosartorya, Neocosmospora, Penicillium and Thielavia are being related by first time as inulinase producers.

Witch's broom (WB) and frost pod rot (FPR) are devastating fungal diseases and responsible for severe losses in cacao trees grown in tropical America. To expand and stabilize the resistance to WB in cacao progenies, as well as to incorporate resistance genes to FPR, 17 genotypes were selected from a structured population. These were used in a second selection cycle, in which four gene donors of FPR resistance were included. All but one of the 59 and 52 progenies differed significantly (P < 0.05) from the susceptible controls Catongo and SIC 23, respectively. Nineteen progenies differed significantly (P < 0.05) from the resistance control SCA 6, suggesting high WB resistance. The direct descendants of cacao genotypes from the Brazilian Amazon and from clones carrying FPR resistance showed lower disease index than the resistant control SCA 6, except for some of the progenies of clone ICS 95, which behaved similarly to the susceptible control. The study highlights nine progenies carrying WB resistance genes from several sources and seven of them from parents carrying frosty pod resistance genes.

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). L. sidoides oil contained 42.33% thymol and 4.56% carvacrol, while L. gracilis oil contained 10% thymol and 41.7% carvacrol. Mycelial growth and conidial production of T. paradoxa were completely inhibited by thymol at a 0.3 μL m -1 concentration. The results suggest that thymol could potentially be used for controlling coconut stem bleeding.

There is a large number of challenges regarding the control of plant diseases in the 21 st century. The use of chemicals has currently become restricted due to problems caused to the environment, as well as the high costs involved and the potential risk of the emergence of pathogen RESUMO ABSTRACTResistance induction through the use of chemical inducers often results in physiological costs to the plant. In this study, induced resistance in cotton plants was evaluated with regard to physiological costs in a cultivar susceptible to Colletotrichum gossypii var. cephalosporioides (CNPA GO 2002 -7997). Plants were cultivated in substrates with two levels of nitrogen and received two applications of acibenzolar-S-methyl (ASM), jasmonic acid (JA) and Agro-M os ® ( AM ) d i s e a s e r e s i s t a n c e i n d u c e r s . P l a n t h e i g h t ( H ) , internodal length (IL), shoot fresh weight (SFW), root fresh weight (RFW), shoot dry weight (SDW) and root dry weight (RDW) were evaluated. The activity of the phenylalanine ammonia lyase (PAL) and peroxidase (POX) was also determined. The plants treated with ASM presented high physiological costs with an accentuated reduction in H, SFW and SDW, whereas those treated with JA Barbosa, M.A.G.; Laranjeira, D.; Coelho, R.S.B. Physiological cost of induced resistance in cotton plants at different nitrogen levels. Summa Phytopathologica, v.34, n.4, p.338-342, 2008 Keywords: acibenzolar-S-methyl, jasmonic acid, Agro-Mos, phenylalanine ammonia lyase and peroxidase. exhibited a significant increase in SDW, and did not significantly differ from H and IL. In the potting mix supplemented with nitrogen, all inducers differed from the control treatment regarding to internodal length, whereas only ASM and AM presented a significant difference between one another in the potting mix without the addition of nitrogen. Significant correlations (P=0.05) were found for most of the variables analyzed, with greater correlations observed between SFW and SDW (0.94); IL and H (0.74); SFW and H (0.70); and SDW and H (0.70). ASM induced the leas t amount of PAL acti vity, significantly differing from the remaining treatments. Greater POX activity was observed in ASM, which significantly differed from the control. AM and JA, however, presented lower activity than the control with regard to these enzymes, and it was not possible to confirm induction resistance in these two treatments.Palavras-chave adicionais: acibenzolar-S-metil, ácido jasmônico, Agro-Mós ® , fenilalanina amônia liase e peroxidase.A indução de resistência pelo uso de indutores químicos tem resultado algumas vezes em custo fisiológico para a planta. A resistência induzida em algodoeiro foi avaliada quanto ao custo fisiológico em uma linhagem suscetível a Colletotrichum gossypii var. cephalosporioides (CNPA GO 2002 -7997) que foi cultivada em substratos com dois níveis de nitrogênio e receberam duas a p l i c a ç õ e s d o s i n d u t or e s a c i b e n z o l a r -S -m e t i l ( AS M ) , á c i d o jasmônico (AJ) e Agro-Mós® (AM). As ...

Anthracnose is an important disease of bell pepper (Capsicum annuum) in Brazil and worldwide. This research investigated the efficacy of plant extracts for control of this disease in bell pepper fruits caused by Colletotrichum acutatum under controlled conditions and analyzed the best treatments in relation to different extract and inoculum concentrations, pathogen isolates, and temperatures. In the preliminary screening, among aqueous or ethanolic extracts of 16 plant species evaluated, the best were 6% aqueous garlic, mallow, and ginger extracts, which reduced disease severity by more than 97%. Garlic extract required the highest concentrations to reduce severity by 75% (CL 75 ) when compared to ginger and mallow extracts, but exhibited the best efficacy in relation to different inoculum concentrations and isolates of C. acutatum. It was also able to maintain greater than 90% efficacy at 20-30 o C. The garlic aqueous extract effectively controlled anthracnose caused by C. acutatum in bell pepper fruits under controlled conditions.