The Pathology of Hypodermella laricis on Larch, Larix Occidentalis

Cohen, Leon I.

doi:10.2307/2440893

Cited by 7 publications

(6 citation statements)

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“…Abscission is the shedding of plant organs when they become non‐functional, damaged or infected (Sexton and Roberts, 1982; Clements and Atkins, 2001). Non‐abscission has been reported in mutants of Lupinus angustifolius (Clements and Atkins, 2001) and in several host–pathogen complexes (Cohen, 1967; Rivera and Wright, 1999) including the bacteria‐mediated witches’ broom disease of pea (Oduro and Munnecke, 1975). There is however, a dearth of quantitative information on the underlying physiological responses of diseased plants with persistent non‐photosynthetic cotyledons.…”

Section: Introductionmentioning

confidence: 99%

Effect of Crinipellis perniciosa Infection on Abscission of Cacao Cotyledons, Reserve Mobilization and Dry Matter Partitioning

Motilal¹,

Sirju‐Charran²,

Sreenivasan³

2003

Journal of Phytopathology

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Infection by Crinipellis perniciosa on cacao seedlings prevented the abscission of cotyledons which normally abscise within 32–61 days from seed sowing. The early growth and development of control and artificially inoculated seedlings was investigated for root dry mass (RDM), shoot dry mass (SDM), shoot‐to‐root ratio (SRR), total dry mass (TDM), cotyledonary dry mass (CDM) and cotyledonary water content (CWC). Cotyledonary reserve mobilization was estimated at 69 and 56% at 5 weeks and 79 and 64% at 8 weeks in control and infected seedlings, respectively. Infection induced the enlargement of tissues but was not accompanied by an increase in dry mass. Infection both delayed and reduced the utilization of cotyledonary food reserves resulting in slower accumulation of RDM, SDM and TDM culminating in a reduction of growth by a factor of 1.6 at 8 weeks. However, the SRR of inoculated plants was similar to that of control plants, suggesting that the balance between the root and shoot systems exists which is unchanged by the effect of the pathogen. CWC was decreased upon senescence to an average of 65% at abscission. The prevention of cotyledonary abscission in infected seedlings is suggested to be due in part to the CDM remaining above a critical level of 20% of the initial CDM. The implication of this response in relation to the infection biology of the pathogen is discussed.

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Section: Introductionmentioning

confidence: 99%

Effect of Crinipellis perniciosa Infection on Abscission of Cacao Cotyledons, Reserve Mobilization and Dry Matter Partitioning

Motilal¹,

Sirju‐Charran²,

Sreenivasan³

2003

Journal of Phytopathology

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“…In contrast to infection-triggered foliage abscission, infection of larch (Larix ) foliage by Hypodermella laricis Tuboef can stop natural abscission, thereby keeping the foliage as a continuing source of inoculum (Cohen 1987).…”

Section: Pathogen-induced Simulations Of Phenologymentioning

confidence: 99%

Putative biotic drivers of plant phenology :with special reference to pathogens and deciduousness

Burdon

Bartlett

2021

Preprint

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Plant phenology is manifested in the seasonal timing of vegetative and reproductive processes, but also has ontogenetic aspects. The adaptive basis of seasonal phenology has been considered mainly in terms of climatic drivers. However, some biotic factors as likely evolutionary influences on plants’ phenology appear to have been under-researched. Several specific cases of putative biotic factors driving plant phenology are outlined, involving both herbivores and pathogens. These illustrate the diversity of likely interactions rather than any systematic coverage or review. Emphasis is on woody perennials, in which phenology is often most multi-faceted and complicated by the ontogenetic aspect. The complete seasonal leaf fall that characterises deciduous plants may be a very important defence against some pathogens. Whether biotic influences drive acquisition or long-term persistence of deciduousness is considered. In one case; of leaf rusts in poplars, countervailing influences of the rusts and climate suggest persistence. Often, however, biotic and environmental influences likely reinforce each other. The timing and duration of shoot flushing may in at least some cases contribute to defences against herbivores, largely through brief periods of ‘predator satiation’ when plant tissues have highest food value. Wide re-examination of plant phenology, accommodating the roles of biotic factors and their interplays with environments as additional adaptive drivers, is advocated, towards developing and applying hypotheses that are observationally or experimentally testable.

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“…Cohen [20] described how the abscission zone is formed in healthy and diseased larch needles and found that the infection triggers H. laricis to form a typical black band at the base of each diseased needle very early after infection. This is most probably related to the disruption of the normal abscission mechanism, which keeps the needles attached for the duration of the life cycle, and often even much longer, according to past outbreaks.…”

Section: Hypodermella Laricis Tubmentioning

confidence: 99%

“…This is most probably related to the disruption of the normal abscission mechanism, which keeps the needles attached for the duration of the life cycle, and often even much longer, according to past outbreaks. Hypodermella laricis has been reported to have a one-year life cycle (e.g., [20]). Hysterothecia develop in the needles that hang from the spur shoots, i.e., short or dwarf shoots.…”

Section: Hypodermella Laricis Tubmentioning

confidence: 99%

“…The youngest spur shoots, initiated in the previous year, recover by producing new needles in the same year of infection (Figure 2a), thus showing clear greening towards the end of the summer. However, older spur shoots die if needles of the spur shoots are infected in two consecutive years [20], causing severe and permanent crown thinning, especially in the canopy of European larch.…”

Section: Hypodermella Laricis Tubmentioning

confidence: 99%

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Synthesis and New Observations on Needle Pathogens of Larch in Northern Finland

Jalkanen

2016

Forests

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Needle pathogens of larch (Larix spp.) in the Nordic countries are under-studied. Their incidence in Finland tends to be low and local, and this may be a function of enemy release, since species of larch were introduced to the region. Here, the ecology and incidence of larch needle pathogens and the abiotic factors that also affect larch in northern Finland are reviewed. Field observations and related laboratory analyses during the past 35 years have mainly been obtained near the Kivalo Research Area within the Arctic Circle, Finnish Lapland. The relatively recent introduction of Hypodermella laricis is a primary focus. This pathogen is not only new to Nordic countries, but can cause severe outbreaks, defoliation and crown-thinning in the canopies of all ages of most planted larch species worldwide. Symptoms of H. laricis clearly differ from those of Mycosphaerella laricina; the latter has affected Larix sibirica at high latitudes for decades. The effects of Meria laricis, Lophodermium laricinum, various rust fungi, and wind and frost are also discussed.

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The Pathology of Hypodermella laricis on Larch, Larix Occidentalis

Cited by 7 publications

References 0 publications

Effect of Crinipellis perniciosa Infection on Abscission of Cacao Cotyledons, Reserve Mobilization and Dry Matter Partitioning

Effect of Crinipellis perniciosa Infection on Abscission of Cacao Cotyledons, Reserve Mobilization and Dry Matter Partitioning

Putative biotic drivers of plant phenology :with special reference to pathogens and deciduousness

Synthesis and New Observations on Needle Pathogens of Larch in Northern Finland

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