The principal rots of English oak,

At head of title: Department of scientific and industrial research. Forest products research.

Developing a commercial hot water treatment to control post-harvest rots on ‘Fiji Red’ papaya

Fiji exports approximately 800 t year-1 of 'Solo Sunrise' papaya marketed as 'Fiji Red' to international markets which include New Zealand, Australia and Japan. The wet weather conditions from November to April each year result in a significant increase in fungal diseases present in Fiji papaya orchards. The two major pathogens that are causing significant post-harvest losses are: stem end rot (Phytophthora palmivora) and anthracnose (Colletotrichum spp.). The high incidence of post-harvest rots has led to increased rejection rates all along the supply chain, causing a reduction in income to farmers, exporters, importers and retailers of Fiji papaya. It has also undermined the superior quality reputation on the market. In response to this issue, the Fiji Papaya industry led by Nature's Way Cooperative, embarked on series of trials supported by the Australian Centre for International Agricultural Research (ACIAR) to determine the most effective and economical post-harvest control in Fiji papaya. Of all the treatments that were examined, a hot water dip treatment was selected by the industry as the most appropriate technology given the level of control that it provide, the cost effectiveness of the treatment and the fact that it was non-chemical. A commercial hot water unit that fits with the existing quarantine treatment and packing facilities has been designed and a cost benefit analysis for the investment carried out. This paper explores the research findings as well as the industry process that has led to the commercial uptake of this important technology.

Ripening and quality responses of avocado, custard apple, mango and papaya fruit to 1-methylcyclopropene

The potential for the ethylene binding inhibitor, 1-methylcyclopropene, to delay ripening of 'Hass' avocado, 'African Pride' custard apple, 'Kensington Pride' mango and 'Solo' papaya was examined. Fruit were gassed with 25 muL/L 1-methylcyclopropene for 14 h at 20 degreesC, followed by treatment with 100 muL/L ethylene for 24 h, and then ripened at 20 degreesC. Ethylene treatment alone generally halved the number of days for fruit to reach the ripe stage, compared with untreated fruit. 1-Methylcyclopropene treatment alone increased the number of days to ripening by 4.4 days (40% increase), 3.4 days (58%), 5.1 days (37%) and 15.6 days (325%) for avocado, custard apple, mango and papaya, respectively, compared with untreated fruit. Applying 1-methylcyclopropene to the fruit before ethylene prevented the accelerated ripening normally associated with ethylene treatment, so that the number of days to ripening for fruit treated with 1-methylcyclopropene plus ethylene was similar to the number of days to ripening for fruit treated with 1-methylcyclopropene alone. 1-Methylcyclopropene treatment was associated with slightly higher severity of external blemishes in papaya and custard apple, slightly higher rots severity in avocado, custard apple and papaya, and at least double the severity of stem rots in mango, relative to fruit not treated with 1-methylcyclopropene. Thus, 1-methylcyclopropene treatment has the potential to reduce the risk of premature ripening of avocado, custard apple, mango and papaya fruit due to accidental exposure to ethylene. However, additional precautions may be necessary to reduce disease severity associated with 1-methylcyclopropene treatment.

Rootstocks influence 'Hass' avocado fruit quality and fruit minerals

To determine the potential for rootstocks to improve avocado quality, 'Hass' fruit from trees on seedling 'Velvick' (SV), clonal 'Velvick' (CV) or clonal 'Duke 7' (CD) rootstocks were harvested in 1999 and 2000, ripened at 20 C immediately after harvest (non-stored) or stored at 5 C for four weeks (stored), and then fruit quality and mineral concentrations determined. In 2000, non-stored CV fruit had lower severity of body rots (5% of flesh volume affected, caused mainly by Colletotrichum gloeosporioides) than CD fruit (20%), while body rots severity in stored CV fruit was 20% compared with 38% in stored CD fruit. Stored CV fruit had less severe diffuse discoloration (3% and 9% in 1999 and 2000, respectively) than CD fruit (7% and 20%, respectively). Stored CV fruit also had less severe vascular browning (19%) than CD fruit (33%) in 2000. In both seasons, CV fruit had 15-19% higher flesh calcium concentrations, 17-22% higher flesh boron concentrations, and 14-15% lower flesh nitrogen concentrations than CD fruit. In 2000, CV fruit also had 27% more skin calcium and 14% less skin nitrogen than CD fruit. There were no effects of rootstock on yield, canopy volume, measured length of non-suberized roots, average fruit weight, fruit length: width ratio, skin thickness, dry matter, proportion of the fruit skin purple-black when ripe, or seed mass: fruit weight ratio. These results suggest that there is potential to improve 'Hass' avocado quality through rootstock selection, and that tree and fruit mineral concentrations have a role in this relationship.

HLA class II antigens (DR, DQ LOCI) and peripheral arthritis in ankylosing spondylitis.

Fifty one patients with ankylosing spondylitis (AS) were typed for HLA-A, B, C, DR, and DQ antigens. The antigen frequencies were compared with those of a normal population and with a B27 positive control group. All but one of the patients with AS were HLA-B27 positive. A positive linkage disequilibrium between Cw1, Cw2, DR1, and the B27 antigen was observed. Patients with AS showed a significant increase in DQw2 antigen compared with the B27 positive control group. No differences in antigenic frequencies were observed in patients having peripheral arthritis and patients with only axial involvement. Seven out of nine patients (78%) with an erosive peripheral arthritis were DR7 positive, suggesting that DR7 or genes closely linked could be related with a more aggressive peripheral joint involvement in patients with AS.

Amyloid arthropathy in patients undergoing periodical haemodialysis for chronic renal failure: a new complication.

Seven patients (five male and two female) with chronic renal failure (CRF) treated by periodical haemodialysis presented with swelling and effusion of more than three months' duration in knees (four bilateral), shoulders (two, one of them bilateral), elbow (one), and ankle (one). Four had a carpal tunnel syndrome both clinically and electromyographically (three bilateral). All patients had hyperparathyroidism secondary to their CRF, which was not due to amyloidosis in any of them. The dialysis duration period varied from five to 14 years, with an average of 8.6 years. Amyloid deposits (Congo red positive areas with green birefringence under polarising microscopy) were shown in six of the seven synovial biopsy specimens of the knee, in five of the sediments of the synovial fluids, and in specimens removed during carpal tunnel syndrome surgery. No amyloid was found in the biopsy specimen of abdominal fat of six of the patients. The finding of amyloid only in the synovial membrane and fluid, and carpal tunnel, its absence in abdominal fat, and the lack of other manifestations of generalised amyloidosis (cardiomyopathy, malabsorption syndrome, macroglossia, etc.) and of Bence Jones myeloma (protein immunoelectrophoresis normal) raises the possibility that this is a form of amyloidosis which is peculiar to CRF treated by periodical haemodialysis.

Necrotrophic fungi associated with epidermal microcracking caused by chilling injury in pickling cucumber fruit

The objective of this work was to visualize the association between microcracking and other epidermal chilling injury symptoms, and to identify rots in cucumber fruit (Cucumis sativus L.) by scanning electron microscopy (SEM). Depressed epidermal areas and surface cracking due to damages of subepidermal cells characterized the onset of pitting in cucumber fruit. The germination of conidia of Alternaria alternata, with some of them evident on the fractures in the cultivar Trópico, occurred after damaging on the epidermis. Before, the chilling injury symptoms became visible, Stemphylium herbarum conidia germinated, and mycelium penetrated through the hypodermis using the microcracks as pathway. In the cultivar Perichán 121 the fungus was identified as Botrytis cinerea.

Phytophthora palmivora causando podridão de frutos de mamoeiro no Pará

Phytophthora palmivora was isolated from papaya (Carica papaya) fruit rots, from commercial growth in Capanema County, Pará. The fungus was pathogenic to healthy inoculated fruits and reisolated, fullfiling the Koch postulates. This is the first report of this pathogen on papaya in Pará, Brazil.

Identification of Rhizoctonia solani associated with soybean in Brazil by rDNA-ITS sequences

The aim of this study was to identify isolates of Rhizoctonia solani causing hypocotyl rot and foliar blight in soybean (Glycine max) in Brazil by the nucleotide sequences of ITS-5.8S regions of rDNA. The 5.8S rDNA gene sequence (155 bp) was highly conserved among all isolates but differences in length and nucleotide sequence of the ITS1 and ITS2 regions were observed between soybean isolates and AG testers. The similarity of the nucleotide sequence among AG-1 IA isolates, causing foliar blight, was 95.1-100% and 98.5-100% in the ITS1 and ITS2 regions, respectively. The nucleotide sequence similarity among subgroups IA, IB and IC ranged from 84.3 to 89% in ITS1 and from 93.3 to 95.6% in ITS2. Nucleotide sequence similarity of 99.1% and 99.3-100% for ITS1 and ITS2, respectively, was observed between AG-4 soybean isolates causing hypocotyl rots and the AG-4 HGI tester. The similarity of the nucleotide sequence of the ITS-5.8S rDNA region confirmed that the R. solani Brazilian isolates causing foliar blight are AG-1 IA and isolates causing hypocotyl rot symptoms are AG-4 HGI. The ITS-5.8S rDNA sequence was not determinant for the identification of the AG-2-2 IIIB R. solani soybean isolate.

Incidência de fungos em pós-colheita de banana 'Prata anã'(Musa AAB)

Este trabalho teve por objetivo determinar a ocorrência e a freqüência de fungos em banana 'Prata anã' e elucidar o agente causal das podridões em pós-colheita de frutos provenientes do norte de Minas Gerais. Dois métodos de isolamento foram adotados: diluição em placas, a partir da lavagem de frutos verdes, e direto de frutos maduros. Os fungos Colletotrichum musae, Trichoderma harzianum, Fusarium equisetii, Penicillium sp. Aspergillus parasiticus, Trichothecium roseum, Colletotrichum acutatum, Alternaria sp., Cladosporium musae e Curvularia lunata foram os mais freqüentemente associados aos frutos. A patogenicidade desses fungos foi testada pela substituição de discos da casca de frutos verdes por discos de micélio. Colletotrichum musae apresentou área média lesionada em torno do ponto de inoculação igual a 5,8 cm², enquanto para os demais fungos testados não passou de 1,50 cm². Os resultados mostraram que C. musae é o agente primário das podridões dos frutos examinados com 100 % de incidência e os demais fungos limitaram-se a necrosar os ferimentos em torno do ponto de inoculação. O modo de infecção latente, causada por C. musae, parece favorecer, primeiramente, a colonização interna dos tecidos e, posteriormente, a ação dos fungos oportunistas, que aceleram as podridões nos frutos e na coroa.

Teores de nutrientes na folha, qualidade do suco e massa seca de raizes de laranja-Valência em função da irrigação e fertirrigação

O presente trabalho foi desenvolvido na Área Experimental de Irrigação da Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal/Unesp, com o objetivo de avaliar o efeito da fertirrigação sobre o teor foliar de macro e de micronutrientes, a massa fresca de raízes e a qualidade do suco de frutos em um pomar de laranja-'Valência'. Os tratamentos utilizados foram: (SI) sem irrigação e adubação com fertilizante sólido parcelado em quatro vezes; (MI-100) fertirrigação por microaspersão com 100% da evapotranspiração; (MI-50) fertirrigação por microaspersão com 50% da evapotranspiração; (G-100) fertirrigação por gotejamento com 100% da evapotranspiração; e (G-50) fertirrigação por gotejamento com 50% da evapotranspiração. Os teores de macro e micronutrientes nas folhas não foram alterados pela irrigação, pelos sistemas de fertirrigação e pela lâmina de água aplicada. A acidez total titulável foi superior no tratamento sem irrigação, e a % de suco no fruto e ratio não foram afetadas pelos tratamentos com e sem irrigação. A massa fresca de raiz foi maior nos tratamentos irrigados, porém não foram constatadas para esse parâmetro diferenças entre os sistemas de gotejamento e microaspersão. A maior concentração de raízes ocorreu até 10 cm de profundidade e até 30 cm de distância do emissor.

Compactação do solo no desenvolvimento radicular e na produtividade da soja

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Conservação e qualidade de mangas 'Palmer' submetidas a tratamento com fungicidas e hidrotérmico

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação do sistema radicular da cana-de-açúcar por diferentes métodos

Para decidir qual método de avaliação do sistema radicular, é necessário ponderar sobre os objetivos do trabalho, a cultura em questão e as condições em que ela se desenvolve. O estudo de raízes é muito importante para a compreensão dos diversos fenômenos de crescimento e desenvolvimento da parte aérea, mas exige procedimentos extremamente criteriosos, pois, além de ser trabalhoso, seus resultados são influenciados pela variabilidade físico-química do solo. Objetivou-se, com esta pesquisa, comparar os resultados de cinco métodos de avaliação do sistema radicular, em duas variedades de cana-de-açúcar, em quatro profundidades e em dois sistemas de colheita: mecanizada de cana crua e manual de cana queimada. Foram comparados ao método de avaliação por extração de monólitos e pesagem de massa de raízes secas outros quatro métodos: monólito com medição de comprimento, trado com pesagem de massa seca, perfil com medição de comprimento por meio de imagens digitais e perfil com contagem do número de raízes. Constatou-se que regressões lineares expressaram adequadamente a relação entre os métodos estudados, exceto quando foi utilizado o trado. Os métodos de perfil foram os mais adequados para detectar diferenças entre tratamentos.