No abstract

. An evaluation of antagonism was determined from the score allotted to the percentage of growth of isolates of Trichoderma spp. in relation to the phyto-pathogenic fungi, as well as the percentage inhibition in pathogen growth in relation to the Compost Aid ® product. The survival of resistance structures in the pathogenic fungi was evaluated 40 days after application of the treatments by plating onto a semiselective culture medium and BDA. For the experiment in vitro, all the treatments with Trichoderma produced a percentage inhibition greater than 50% for both phyto-pathogenic fungi. The commercial products Tricobiol ® and Triconemate ® gave the greatest percentage inhibition for the fungus S. rolfsii (62.5%). The Compost Aid ® product gave 100% and 98.57% inhibition in the growth of the fungi M. phaseolin and S. rolfsii respectively. The treatments in the form of a mixture of Trichoderma and Tricobiol ® had a median value of 100%, while Triconemate ® resulted in a 96% inhibition in the growth of the microsclerotia of M. phaseolina recovered from the soil; however none of these treatments inhibited sclerotial germination in S. rolfsii. The product Compost Aid ® resulted in a median of 100% and 0% growth in resistance structures for the M. phaseolina and S. rolfsii fungi respectively.

Root diseases represent one of the main reasons for yield loss in melon crops, especially root and stem rots caused by pathogens like the fungi Fusarium solani (Fs), Macrophomina phaseolina (Mp) and Rhizoctonia solani (Rs), frequently observed in muskmelon either alone or in combination. The objective of this study was to evaluate the effect of the interaction between the pathogens Fs, Mp and Rs on the incidence and severity of root rot and muskmelon development. Two greenhouse experiments were performed using plastic pots with substrate infested with each pathogenic agent alone or in combination. The second experiment was conducted in the same pots that were used in the first experiment. In the first experiment, the disease incidence was higher for the treatment with Fs alone. In the second experiment, the disease incidence and severity were greater for treatment Fs + Rs than for Fs alone. Macrophomina phaseolina was the most commonly isolated pathogen when applied to the plants in a paired mixed inoculum (Fs + Mp and Mp + Rs) in the first experiment. In the second experiment, Fs was more prevalent than the other studied pathogens. Soil infested with Fs had the lowest fresh weight of muskmelon. The pathogens Fs and Mp were more competitive than Rs.

PALAVRAS-CHAVE Melão Fusarium solani Materiais vegetais Patógenos habitantes do solo KEYWORDS Melon Fusarium solani Soilborne pathogens Plant material RESUMO: O cultivo contínuo e intensivo do meloeiro tem proporcionado aumento na incidência e severidade de doenças causadas por patógenos habitantes do solo que apresentam difícil controle. O objetivo do trabalho foi verificar o efeito da adubação verde sobre o controle da fusariose do meloeiro. O experimento foi conduzido em casa de vegetação e o delineamento experimental utilizado foi o de blocos ao acaso com os tratamentos arranjados em esquema fatorial 2x2x4 [2 (solo esterilizado e não esterilizado) x 2 (solo infestado e não infestado com Fusarium solani) x 4 (solo com crotalária; solo com milheto; solo com mistura de feijão de porco + milheto e solo sem adubação verde)] e oito repetições. Foram avaliadas a incidência e a severidade da podridão radicular e as massas das matérias fresca e seca do meloeiro. A crotalária quando incorporada ao solo, esterilizado ou não, proporcionou menor incidência e severidade da podridão radicular em relação aos demais tratamentos. Em solo não esterilizado e não infestado, a incorporação de adubos verdes (crotalária, milheto e feijão de porco + milheto), propiciaram menor incidência e severidade da doença, quando comparado ao solo sem adubo verde. A incorporação de crotalária e feijão de porco + milheto ao solo proporcionaram maiores massas de matérias fresca e seca do meloeiro, sendo que a incorporação de crotalária proporcionou aumento de 66,39 e 67,13% a mais de matéria fresca e seca respectivamente, em relação ao solo sem adubo verde. A incorporação de milheto propiciou menor massa da matéria fresca e seca das plantas.

Controlling post-harvest papaya diseases without using agrochemicals is a challenge for producers. This study aimed at evaluating the effect of clove essential oil, biological fungicide (Trichodermil®), resistance inducer (Cob Sistem®) and chemical fungicide (Imazacure®) on the in vitro control of phytopathogenic fungi isolates from papaya as well as on the post-harvest quality of Tainung 1 papaya. The in vitro experiment was conducted in a complete randomized design, with five fungal species x five treatments and five replications. The in vivo experiment was conducted in a complete randomized design, with five treatments x five storage times, five replications and three fruits per replication. The fruits were stored under refrigeration at 10 ± 2 ºC and 90 ± 5 % of relative humidity and evaluated at 0, 7, 14, 21 and 28 days of storage, plus two shelf life days at 25 ± 2 ºC, to simulate marketing conditions. The inhibition of mycelial growth was evaluated in the in vitro experiment, while the diseases occurrence and post-harvest quality of the fruits were evaluated in the in vivo experiment. The clove essential oil and Trichodermil® were as efficient as Imazacure® in inhibiting the mycelial growth of Alternaria sp., Colletotrichum gloeosporioides and Rhizopus sp. The treatments with clove essential oil, Trichodermil® and Imazacure® were similar in controlling the pathogens up to 21 days of storage. The treatments had no effect on the fruits soluble solid contents.