Factors affecting discharge, germination and viability of spores of Microcyclus ulei

Chee, K. H.

doi:10.1016/s0007-1536(76)80221-5

Cited by 19 publications

(9 citation statements)

References 2 publications

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“…Stahel () claimed that the epidemiological significance of ascospores is limited, because he was able to collect only very few viable ascospores and none of them when the young, susceptible leaves emerged. Chee () confirmed that ascospores usually lose viability within a few days but can retain some viability for a maximum of 3 weeks. However, the reported 1–5 month period of perithecium maturity (Langford, ; Holliday, ; Chee, ; Medeiros, ) could allow the fungus to survive between two successive wet seasons, allowing a resumption of epidemics in the second season.…”

Section: Introductionmentioning

confidence: 96%

“…Chee () confirmed that ascospores usually lose viability within a few days but can retain some viability for a maximum of 3 weeks. However, the reported 1–5 month period of perithecium maturity (Langford, ; Holliday, ; Chee, ; Medeiros, ) could allow the fungus to survive between two successive wet seasons, allowing a resumption of epidemics in the second season. The cool temperatures (13–16°C) required for ascospore release (Holliday, ; Chee, ) are not common in Amazonia, especially in coastal French Guiana.…”

Section: Introductionmentioning

confidence: 99%

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Role of ascospores and conidia in the initiation and spread of South American leaf blight in a rubber tree plantation

et al. 2013

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Microcyclus ulei, the fungus causing South American leaf blight (SALB) on rubber tree leaves, produces two main types of spores: ascospores and conidia. To assess their respective epidemiological role, a field experiment was conducted in French Guiana over 3 years. Tree phenology, disease severity and climate variables were recorded while airborne spores were trapped and quantified. Ascospores were shown to play an essential role in the perpetuation of the disease outside the host's growth periods, in the resumption of epidemics, and in the spread of the disease to disease-free zones. Conidia were trapped in visibly infected plots only, during periods of host growth. Disseminated over short distances and present only temporarily on leaves, the conidia enabled the disease to spread stepwise when the climate was conducive. Segmentation analysis revealed that the duration of high relative humidity was the climatic variable most related to ascospore trapping. Ascospore release did not require low temperatures. Considering the essential role of the ascospores in the initiation and spread of disease, artificial defoliation as a means of reducing the inoculum pressure during tree refoliation is proposed to control SALB. To check the validity of this method, a survey over several years of natural defoliation-refoliation in relation to climate and other leaf diseases is needed.

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Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Role of ascospores and conidia in the initiation and spread of South American leaf blight in a rubber tree plantation

et al. 2013

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“…Asexual sporulation occurs on the still immature leaves, principally on their underside, about 7 days after infection, while sexual structures (stromata) appear on the margin of the necrosis once the leaves reach maturity (about 3 weeks after budburst). Ascospores are produced 1 to 5 months after infection (Langford 1945;Holliday 1970;Chee 1976a;Medeiros 1976), but without experimental evidence.…”

Section: Introductionmentioning

confidence: 99%

Influence of host resistance and phenology on South American leaf blight of the rubber tree with special consideration of temporal dynamics

Guyot¹,

Cilas²,

Sache

2007

Eur J Plant Pathol

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South American leaf blight (SALB), the most dangerous disease of the rubber tree, is responsible for the lack of significant natural rubber production in South America and is a major threat to rubber tree plantations in Asia and Africa. Although the selection of resistant clones is the preferred disease control method, greater knowledge is required of the relationship between host and pathogen, in order to construct more durable resistance. Based on small-scale trials, this study set out to compare the dynamics of SALB on two highly susceptible and one moderately susceptible clone and to analyse the effect of host phenology on disease severity, at leaflet and flush scales. Clonal resistance was found to have a noticeable effect on disease severity, asexual sporulation and stromatal density at both leaflet and flush levels, and on disease dynamics at a leaflet level; time for symptom and sporulation appearance were longer on the moderately susceptible clone than on the susceptible clones. On the moderately susceptible clone, the stromatal density was largely dependent on disease severity. The phenology did not differ among the three clones and could not be considered as a factor in genetic resistance to SALB. However, for the three clones, the position of the leaflet in the flush affected the duration of the immature stages and the disease: the shorter the duration of leaflet development, the lower the disease severity, the sporulation intensity and the stromatal density.

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“…Askospora dan konidium M. ulei diketahui mampu bertahan hidup pada kondisi ekstrem dan dalam waktu yang cukup lama, baik pada komoditas pertanian maupun material lainnya. Konidium M. ulei yang diletakkan pada kaca objek dan disimpan dalam desikator selama 16 minggu masih mampu berkecambah, sementara askospora yang disimpan dalam desikator juga masih mampu bertahan hidup selama 15 hari (Chee 1976). Selain itu, konidium M. ulei yang disimpan selama 7 hari pada kertas, kaca, plastik, kulit sintetis, pakaian, besi, tanah kering dan tanah basah juga masih mampu berkecambah sebesar 5.8-31.6% (Hashim 2007).…”

Section: Pendahuluanunclassified

Keefektifan Perlakuan Panas Kering dan Iradiasi UV-C untuk Mematikan Cendawan Model Microcyclus ulei

Cristin¹,

Sinaga

Adnan

2013

jfi

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ABSTRAKStudi dilakukan untuk mengembangkan metode perlakuan serta menentukan dosis efektif perlakuan panas kering dan iradiasi UV-C yang dapat mematikan cendawan model Microcyclus ulei pada biji dan bungkil kedelai tanpa merusak kandungan nutrisinya. Cendawan model yang digunakan ialah Colletotrichum gloeosporioides, Botryodiplodia theobromae, Fusarium oxysporum f. sp. niveum, dan Sclerotium rolfsii. Perlakuan iradiasi UV-C pada jarak 15 dan 30 cm dari lampu UV-C dengan waktu dedah 12 dan 24 jam tidak efektif membunuh biakan semua cendawan model uji di medium PDA. Perlakuan panas kering pada suhu 55 °C selama 30 dan 60 menit efektif mematikan biakan C. gloeosporioides, B. theobromae, dan S. rolfsii pada medium PDA, kecuali F. oxysporum f. sp. niveum. Pengujian pada kedelai menunjukkan bahwa perlakuan suhu 55 °C selama 30 menit efektif mematikan konidia C. gloeosporioides, B. theobromae, dan F. oxysporum f. sp. niveum, tanpa merusak kandungan protein total kedelai, tetapi perlakuan panas kering pada suhu 60 °C selama 60 menit tidak efektif mematikan sklerotia S. rolfsii. Apabila sifat tahan M. ulei menyerupai S. rolfsii, akan diperlukan suhu dan waktu perlakuan panas yang lebih tinggi daripada yang dilakukan dalam pengujian ini.Kata kunci: Botryodiplodia theobromae, bungkil kedelai, dosis efektif, Colletotrichum gloeosporioides, Fusarium oxysporum f. sp. niveum, Sclerotium rolfsii ABSTRACTThis study was carried out to develop treatment methods and determine the effective dose of dry heat treatment and UV-C irradiation to kill the fungus models of Microcyclus ulei on soybean grains and soybean meals without damaging its nutritional content. The fungus models used in this study were Colletotrichum gloeosporioides, Botryodiplodia theobromae, Fusarium oxysporum f. sp. niveum, and Sclerotium rolfsii. The results showed that UV-C treatment up to 12 and 24 hours exposure time at 15 and 30 cm from UV-C light was not effective to kill all fungus models in PDA. Dry heat treatment at 55 °C for 30 and 60 minutes was effective to kill cultures of C. gloeosporioides, B. theobromae, and S. rolfsii in PDA, except for F. oxysporum f. sp. niveum. Further experiments on soybean showed that dry heat treatment at 55 °C for 30 minutes was effective to kill conidia of C. gloeosporioides, B. theobromae, and F. oxysporum f. sp. niveum, without damaging its protein content. However, dry heat treatment at 60 °C for 60 minutes has been proved not effective to kill sclerotia of S. rolfsii. If M. ulei had the similar resistance as S. rolfsii, then it would need a higher temperature and time than used in this study to kill the fungus.

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Factors affecting discharge, germination and viability of spores of Microcyclus ulei

Cited by 19 publications

References 2 publications

Role of ascospores and conidia in the initiation and spread of South American leaf blight in a rubber tree plantation

Role of ascospores and conidia in the initiation and spread of South American leaf blight in a rubber tree plantation

Influence of host resistance and phenology on South American leaf blight of the rubber tree with special consideration of temporal dynamics

Keefektifan Perlakuan Panas Kering dan Iradiasi UV-C untuk Mematikan Cendawan Model Microcyclus ulei

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