Monosporascus cannonballus causal agent of collapse in melon plants in the State of Rio Grande do Norte, Brazil A pathogenicity test has verified that Monosporascus cannonballus is, in fact, the etiological agent causing the collapse of

-The effect of plant materials [Sunn Hemp (Crotalaria juncea), Castor Bean (Ricinus communis L.), Cassava (Manihot esculenta Crantz) and Neem (Azadirachta indica)] and the times of incorporation of these materials in regards to the incidence of root rot in melon was evaluated in Ceará state, Brazil. The experiment was conducted in a commercial area with a history of root pathogens in cucurbitaceae. The randomized block design was used, in a 5 x 3 factorial arrangement with four repetitions. The treatments consisted of a combination of four plant materials (sunn hemp, castor beans, cassava and neem) and a control with no soil incorporation of plant material and three times of incorporation (28, 21, and 14 days before the transplanting of the seedlings). Lower incidence of root rot was observed in practically all of the treatments where materials were incorporated at different times, with variation between the materials, corresponding with the time of incorporation, in relation to the soil without plant material. The pathogens isolated from the symptomatic muskmelon plants were Fusarium solani, Macrophomina phaseolina, Monosporascus cannonballus and Rhizoctonia solani, F. solani being encountered most frequently. Resumo -Avaliou-se o efeito de materiais vegetais [Crotalária (Crotalaria juncea), Mamona (Ricinus communis L.), Cassava (Manihot esculenta Crantz) e Nim (Azadirachta indica)] e do tempo de incorporação destes sobre a incidência de podridões radiculares no meloeiro, no estado do Ceará, Brasil. O experimento foi conduzido em área comercial com histórico de patógenos radiculares em cucurbitáceas. O delineamento utilizado foi de blocos casualizados, em esquema fatorial 5 x 3, com quatro repetições. Os tratamentos consistiram da combinação de quatro materiais vegetais (crotalária, mamona, mandioca brava e nim) mais uma testemunha com solo sem incorporação de material vegetal e três tempos de incorporação (28, 21, e 14 dias antes do transplantio das mudas). Menor incidência de plantas com podridão radicular foi observada em praticamente todos os tratamentos onde se incorporou materiais nos diferentes tempos, com variação entre os materiais, conforme o tempo de incorporação, em relação ao solo sem material vegetal. A crotalária proporcionou menor incidência quando a incorporação foi de 14 dias e à medida que aumentou o tempo, houve acréscimo na porcentagem de plantas com podridão. Quando se utilizou a mandioca, houve redução da podridão, proporcionalmente ao tempo de incorporação.

The objective of the present work was to evaluate the use of extracts of leaves and fruits of neem (Azadirachta indica Juss) as coating for papaya Formosa fruits aiming to maintain their quality during post-harvest storage. A completely randomized experimental design in a 5x5 factorial arrangement was used, with 3 replications of 2 papaya fruits per plot. The treatments consisted of five coatings with extracts of neem leaves and fruits (leaf extracts at 5 and 10%, fruit extracts at 5 and 10% and a control treatment without coating) and five storage periods (0, 3, 6, 9 and 12 days) under mean temperature of 30.4 °C and relative humidity of 42%. The fruit weight loss, external appearance, pulp firmness, titratable acidity and soluble solids were evaluated, and the fungi species on the fruit surface of each storage were identified and quantified. The treatments with extract of neem leaves and fruits at 5% had papaya fruits with best external quality and provided best control of growth of phytopathogenic fungi. Regarding external appearance, papaya fruits coated with extracts of neem leaves and fruits at 5% had a shelf life of 12 days, while those coated with extracts at 10% had a shelf life of 9 days.

Monosporascus root rot and vine decline (MRRVD) is an important disease in the melon crop in Brazil. In our research, we evaluated the reaction of 45 melon genotypes to M. cannonballus in two successive cropping seasons in a greenhouse. Melon seedlings were transplanted into naturally infested soil. The evaluation of the genotypes was performed after 55 days, using a score scale to group each genotype into one of five classes and to calculate the disease severity index. None of the genotypes showed an immune reaction to M. cannonballus, regardless of the season. In the first cycle, only 28.9% ('AF 464', 'Auraprince', 'DRG 2278', 'Estoril', 'Guaporé', 'Kousto', 'Mabel', 'Magisto', 'Massaï', 'Nectar', '8530', 'RZ 34130' and 'RZ 34292') had a similar reaction to the high resistance to the MRRVD. Most genotypes (66.7%) behaved as moderately resistant while 4.4% were susceptible and none were highly susceptible. Conversely, in the second cycle, no genotype showed a reaction similar to high resistance while 42.2% behaved as moderately resistant, 48.9% as susceptible, and 8.9% as highly susceptible. The severity levels ranged from 7.5 to 60% and 27.5 to 92.5% for the first and second cycles, respectively. The genotypes 'DRG 2278', 'Estoril', 'Guaporé', 'Kousto', 'Mabel', 'Massaï', 'RZ 34130' and 'RZ 34292' were identified as highly resistant and moderately resistant in the first and second cycles of cultivation, respectively. Therefore, these genotypes are promising sources of resistance to M. cannonballus and should be preferred in commercial fields infested with the pathogen.

. 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.

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RESUMO A incorporação de materiais vegetais no solo pode exercer influência sobre as populações dos patógenos e/ou suas atividades patogênicas. Este trabalho objetivou avaliar o potencial da adubação verde na indução da supressividade ao declínio de monosporascus em solo naturalmente infestado por Monosporascus cannonballus. Foram realizados dois experimentos, um em casa de vegetação e outro em campo. No primeiro, foram comparados 13 tratamentos considerando diferentes combinações do melão pele de sapo e os adubos verdes (Crotalaria spectabilis, C. juncea, Canavalia ensiformis, Cajanus cajan, Dolichos lablab e Stilozobium aterrimum) em quatro ciclos de cultivo. Os maiores valores de severidade da doença foram detectados nos plantios intercalados de C. cajan ou C. spectabilis com meloeiro, e nos cultivos sucessivos de C. ensiformis com incorporação, e meloeiro sem incorporação. Os maiores níveis populacionais de M. cannonballus nos solos foram verificados nos cultivos sucessivos de meloeiro sem incorporação, D. lablab, e nos cultivos intercalados de C. ensiformis, S. aterrimum, C. cajan, C. juncea ou D. lablab com meloeiro. As menores densidades obtidas ao final do experimento de casa de vegetação foram nos solos submetidos à adubação verde sucessiva de C. spectabilis, C. cajan, C. ensiformis, C. juncea e S. aterrimum e no plantio intercalado de C. Juncea. Em campo, o tratamento mais eficiente na redução da severidade do declínio de monosporascus e que apresentou, numericamente, maior número de frutos comerciais de melão foi o tratamento com S. aterrimum.

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.