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Journal ArticleDOI

Incidence and severity of Botryodiplodia die-back in plantations of Albizia falcataria in Kerala, India

01 Apr 1988-Forest Ecology and Management (Elsevier)-Vol. 24, Iss: 1, pp 43-58
TL;DR: Regular observations in a plot with moderately severe infection indicated that the high incidence of die-back occurred during the dry-warm period, but during or just after the monsoon it declined as some of the affected trees recouped partially or completely with the overall incidence gradually declining.
About: This article is published in Forest Ecology and Management.The article was published on 1988-04-01. It has received 10 citations till now. The article focuses on the topics: Falcataria & Albizia.
Citations
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Journal ArticleDOI
30 Dec 2015-PLOS ONE
TL;DR: The diversity patterns of the lichens indicate a loss of species richness and change in species composition in areas where natural resources are still exploited inside the borders of the national park, thus imperative for protected areas to receive more protection to ensure populations of the characteristic species remain viable in the future.
Abstract: Lichens are valuable bio-indicators for evaluating the consequences of human activities that are increasingly changing the earth’s ecosystems. Since a major objective of national parks is the preservation of biodiversity, our aim is to analyse how natural resource management, the availability of lichen substrates and environmental parameters influence lichen diversity in Rodnei Mountains National Park situated in the Eastern Carpathians. Three main types of managed vegetation were investigated: the transhumance systems in alpine meadows, timber exploitation in mixed and pure spruce forests, and the corresponding conserved sites. The data were sampled following a replicated design. For the analysis, we considered not only all lichen species, but also species groups from different substrates such as soil, trees and deadwood. The lichen diversity was described according to species richness, red-list status and substrate-specialist species richness. The variation in species composition was related to the environmental variables. Habitat management was found to negatively influence species richness and alter the lichen community composition, particularly for threatened and substrate-specialist species. It reduced the mean level of threatened species richness by 59%, when all lichen species were considered, and by 81%, when only epiphytic lichens were considered. Management-induced disturbance significantly decreased lichen species richness in forest landscapes with long stand continuity. The diversity patterns of the lichens indicate a loss of species richness and change in species composition in areas where natural resources are still exploited inside the borders of the national park. It is thus imperative for protected areas, in particular old-growth forests and alpine meadows, to receive more protection than they have received in the past to ensure populations of the characteristic species remain viable in the future.

26 citations

Journal ArticleDOI
TL;DR: Widespread dieback of the introduced noxious weed Mimosa pigra was observed during the dry months in monsoonal northern Australia and was suggested that the occurrence of dieback is linked with the establishment of a stem-boring moth introduced as a biological control agent for M. pigra.
Abstract: Widespread dieback of the introduced noxious weed Mimosa pigra was observed during the dry months in monsoonal northern Australia. Stems were girdled by reddish-brown lesions that generally originated from leaf axils. Botryodiplodia theobromae was consistently isolated from the lesions and was shown to cause the symptoms. It is suggested that the occurrence of dieback is linked with the establishment of a stem-boring moth introduced as a biological control agent for M. pigra.

17 citations

Journal ArticleDOI
TL;DR: This study is the first to confirm that L. theobromae is the causal agent of black rot on kenaf seed in Malaysia.
Abstract: Kenaf (Hibiscus cannabinus) is a fibre crop grown in Malaysia as a substitute crop for tobacco. Previous study have recorded that kenaf has been infected by various genera of seed-borne pathogen include Fusarium, Synnematium, Alternaria, Colletotrichum and Botrytis. Seed-borne disease affects and actively attacks seeds and may be harmful. Lasiodiplodia theobromae is a seed-borne fungal pathogen that infects a variety of crop seeds. Studies on the isolation of seed-borne fungi on kenaf seed have revealed that L. theobromae causes black rot disease on kenaf seeds. L. theobromae was successfully isolated from kenaf seeds on an agar plate and a blotter. L. theobromae was isolated frequently from infected seeds and identified based on its cultural and morphological characteristics. The fungus sequence was analysed using molecular technique (ITS-rDNA amplification). A pathogenicity test was used to confirm that L. theobromae caused blackening of the seeds and reduced the germination against a control treatment in potato Dextrose Agar (PDA) medium. To our knowledge, this study is the first to confirm that L. theobromae is the causal agent of black rot on kenaf seed in Malaysia.

12 citations

01 Jan 2011
TL;DR: From the results of this study, it was recommended that G. robusta should not be planted in the semi arid zones of Kenya, due to its susceptibility to the canker and dieback disease.
Abstract: A canker and dieback disease was recently reported on Grevillea robusta in east Africa but little was known about its magnitude, distribution and associated pathogens. In our survey of the disease approximately 36% of 17,994 G. robusta trees assessed showed canker and dieback symptoms. Disease index increased from the humid zone (18%) and to the semi-arid zones (67%). Tree mortality increased from 0.3 to 20% respectively on the same scale and was highest in trees less than 7 years old in all zones. Disease index and tree mortality showed positive correlations with drought period which increased from an average of 0.7 months (humid) to 7 months (semi-arid zones). Both variables showed negative correlations with farm altitude. Disease index was higher in the woodlots compared to other types of tree planting in all zones. Two Botryosphaeriaceae species, Neofusicoccum parvum and Lasiodiplodia theobromae known to be pathogenic on G. robusta were highly abundant in severely diseased stems and branches and their occurrence also showed positive correlations with disease severity. From the results of this study, it was recommended that G. robusta should not be planted in the semi arid zones of Kenya, due to its susceptibility to the canker and dieback disease.

11 citations

Journal ArticleDOI
TL;DR: Pest infestation increased with an increase of L. invasa abundance but decreased with a increase of altitudes, and control efforts needs to focus on controlling the spread of the pest, using silvicultural methods and planting resistant Eucalyptus species.
Abstract: This study explores infestation density of Leptocybe invasa on five commercially grown Eucalyptus species in Coastal, Plateaux, and Southern Highlands agroecological zones of Tanzania. Infestation density between agroecological zones, Eucalyptus species, age classes and tree crown parts, relationship between stand altitudes and the magnitude of infestation, damage index, species age, and abundance of L. invasa on different Eucalyptus species were examined. There were significant differences in infestation between zones and Eucalyptus species. Eucalyptus tereticornis was more affected, followed by E. camaldulensis, and E. saligna was the least while E. grandis and E. citriodora were not affected. No significant differences in damage between different crown parts were observed. Trees with age of 1–3 yr were damaged more than those of age 4–6 yr. Pest infestation increased with an increase of L. invasa abundance but decreased with an increase of altitudes. Control efforts needs to focus on controlling the sp...

9 citations


Cites methods from "Incidence and severity of Botryodip..."

  • ...The average severity (AS) per plot was calculated as described by Sharma and Sankaran (1988): AS = (1 × a) + (2 × b) + (3 × c) + (4 × d) N , where 1, 2, 3, and 4 are severity categories; a, b, c, and d are the number of trees examined in each severity category; and N is the total number of trees…...

    [...]

References
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Journal ArticleDOI
TL;DR: Benomyl (a systemic fungicide) controls soft rot of cassava tubers, and in the presence of light pycnidia are formed.
Abstract: Soft rot of cassava (Manihot utilissima Pohl) was found to be caused by Lasiodiplodia theobromae (Pat.) Griff. & Mobl., Trichoderma harzianum Rifai, Cylindrocarpon candidum (Link) Wollenw., Aspergillus niger van Tieghem and Aspergillusflavus Link. The organisms enter tubers through wounds, bruises and natural openings. High relative humidities (50–100%) favour rot development by L. theobromae, and in the presence of light pycnidia are formed. Benomyl (a systemic fungicide) controls soft rot of cassava tubers.

27 citations

Journal ArticleDOI
TL;DR: A new stem canker disease of Eucalyptus caused by Botryodiplodia theobromae is reported from India and survey and pathogenicity trials suggest that E. tereticornis is more susceptible than E. grandis to stemCanker.
Abstract: A new stem canker disease of Eucalyptus caused by Botryodiplodia theobromae is reported from India. The disease caused up to 20% mortality. Survey and pathogenicity trials suggest that E. tereticornis is more susceptible than E. grandis to stem canker.

25 citations

Journal ArticleDOI
01 Oct 1962-Botany
TL;DR: The bark and wood moisture content of the three varieties was lower during dormancy than in the growing season and in all varieties, there was a significant positive correlation between wood and bark moisture content.
Abstract: A comparison was made between Populus trichocarpa Torr. and Gray, P. × canadensis Moench 'Regenerata', and P. × canadensis 'Robusta Bachelieri' with respect to shoot moisture relations and anatomy. The two hybrid varieties had slower rates of moisture loss and had higher wood moisture contents throughout most of the year than P. trichocarpa. The bark and wood moisture content of the three varieties was lower during dormancy than in the growing season. The upper region of the shoots had lower bark and wood moisture contents than the basal region during dormancy, but the reverse was true in summer. In all varieties, there was a significant positive correlation between wood and bark moisture content. Compared with P. trichocarpa, the two hybrids had larger piths, wider vessels, longer phloem rays, wider sieve tube zones, and thicker periderms; P. 'Robusta' had fewer lenticels. The upper region of the shoots had a wider pith, thicker bark, thinner periderm, and more lenticels than the basal region. The differ...

23 citations

Journal ArticleDOI
01 Jun 1969-Botany
TL;DR: A technique was devised for obtaining extensive canker development on wounded greenhouse-grown aspens inoculated with mycelium of Hypoxylon pruinatum (Klot).
Abstract: A technique was devised for obtaining extensive canker development on wounded greenhouse-grown aspens (Populus tremuloides Mich.) inoculated with mycelium of Hypoxylon pruinatum (Klot.) Cke. Cankers developed rapidly only on water-stressed plants, and under such conditions often averaged 75 mm in length within 10 days. Alcohol treatment of stems before inoculation did not affect the course of canker development. Cankers developed most rapidly on plants watered every third or every fifth day, and developed least in plants watered daily. Stem wounds exposing the wood were essential for canker development. Wounds required an 8-day period before inoculation to heal sufficiently to inhibit canker development. Wound sites midway on the stem were most susceptible to canker development, while sites near the growing point were the least susceptible. Time for symptom appearance was prolonged in inoculated plants of larger diameters.

19 citations