The genus Trichoderma is a potential biocontrol agent against several phytopathogenic fungi. One parameter for its successful use is an efficient coiling process followed by a substantial production of hydrolytic enzymes. The interaction between fifteen isolates of Trichoderma harzianum and the soil-borne plant pathogen, Rhizoctonia solani, was studied by light microscopy and transmission electron microscopy (TEM). Macroscopic observations of fungal growth in dual cultures revealed that growth inhibition of the pathogen occurred soon after contact with the antagonist. All T. harzianum isolates tested exhibited coiling around the hyphae of R. solani. The strains ALL23, ALL40, ALL41, ALL43 and ALL49 did not differ in coiling frequency and gave equal coiling performances. No correlation between coiling frequency and the production of cell wall-degrading chitinases, N-acetyl-beta-D-glucosaminidase and beta-1,3-glucanases, was found.

Trichoderma asperellum produces at least two extracellular L-1,3-glucanases upon induction with cell walls from Rhizoctonia solani. A L-1,3-glucanase was purified by gel filtration and ion exchange chromatography. A typical procedure provided 35.7-fold purification with 9.5% yield. The molecular mass of the purified exo-L-1,3-glucanases was 83.1 kDa as estimated using a 12% (w/v) SDS^electrophoresis slab gel. The enzyme was only active toward glucans containing L-1,3-linkages and hydrolyzed laminarin in an exo-like fashion to form glucose. The K m and V max values for exo-L-1,3-glucanase, using laminarin as substrate, were 0.087 mg ml 31 and 0.246 U min 31 , respectively. The pH optimum for the enzyme was pH 5.1 and maximum activity was obtained at 55 ‡C. Hg 2þ strongly inhibited the purified enzyme.

: This work was carried out to record the species of Anastrepha, their host plants and associated parasitoids in Laranjal do Jari and Vitória do Jari, Amapá State. Fleshy fruits of 17 species of 13 families were sampled, from February to July of 2006, in main districts of both municipalities. Nine species of Anastrepha and six species of braconid parasitoids were sampled during this study.

No abstract

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Bactrocera carambolae Drew & Hancock is a quarantine pest present in Brazil and is the main phytosanitary barrier for the export of fresh fruits from that country. In this work, we evaluated the effect of Amazonian isolates of Metarhizium on kill larvae, pupae, and adults of B. carambolae in soil applications. The mortality of larvae and pupae in sterile soil treated with Metarhizium anisopliae was 70 %. In addition, 100 % of the adults that emerged from this substrate died up to five days later. This isolate caused the mortality of larvae and pupae in non-sterile soil, but its effect was more evident after adult emergence (70 % mortality up to ten days after emergence). Metarhizium robertsii was effective in killing larvae and pupae of the pest, especially in non-sterile soil, and caused a 60 % reduction in adult survival 50 days after emergence. These results indicated the possible use of these isolates for the control of B. carambolae, suggesting the possibility of using this biocontrol mode as another alternative in controlling this quarantine pest.

RESUMO. Este trabalho teve o objetivo de registrar a ocorrência de espécies de Anastrepha e parasitoides associados a frutos de Spondias mombin em três municípios do estado do Amapá, Brasil. Foram realizadas coletas de frutos de S. mombin nos municípios de Oiapoque, Porto Grande e Mazagão (10 amostras por município, cada uma composta por aproximadamente 1 kg de frutos), em fevereiro e março de 2014. Foram obtidos 2.715 pupários, dos quais emergiram 891 espécimes de Anastrepha e 261 de himenópteros. Os índices de infestação foram variáveis, sendo o maior valor médio registrado em Porto Grande (99,8 pupários/kg de fruto). Quatro espécies do gênero Anastrepha foram obtidas: Anastrepha obliqua (Macquart), Anastrepha antunesi Lima, Anastrepha fraterculus (Wiedemann) e Anastrepha striata Schiner. A espécie mais abundante nos três municípios foi A. obliqua. Das 29 amostras infestadas por moscas-das-frutas, apenas sete (24,1%) não apresentaram parasitismo. O maior percentual médio de parasitismo foi registrado em Mazagão (18,9%). Foram obtidos exemplares de cinco espécies de parasitoides: Opius bellus Gahan (50,6% do total), Doryctobracon areolatus (Szépligeti) (26,8%), Asobara anastrephae (Muesebeck) (16,5%), Utetes anastrephae (Viereck) (5,7%) e Aganaspis pelleranoi (Brèthes) (0,4%).

Edited by J Van Staden Mosquitoes, such as Aedes aegypti and Culex quinquefasciatus, are important vectors of diseases, such as dengue fever, chikungunya fever, Zika virus, and filariasis, and these diseases are public health problems. The present study was carried out to evaluate the larvicidal activity of the hydroethanolic extract from leaves of Acmella oleracea leaves against 3rd instar larvae of the Ae. aegypti dengue vector and the Cx. quinquefasciatus filariasis vector. The hydroethanolic extract caused significant mortality in Ae. aegypti and Cx. quinquefasciatus. After 24 h of exposure to the extract, it was possible to establish the LC 50 values for the extract: 11.41 ppm for Ae. aegypti and LC 50 32.40 ppm for Cx. quinquefasciatus. The hydroethanolic extract from leaves of A. oleracea showed very low ecotoxicity suggesting that it can be used without causing environmental damage. This is the first study that shows the use of hydroethanolic extract from leaves of A. oleracea as an alternative to synthetic larvicides to eliminate larvae of Ae. aegypti and Cx. quinquefasciatus in an easy, cheap and safe way.