Fusarium root infection of container-grown Douglas-fir: effect on survival and growth of outplanted seedlings and persistence of the pathogen

Fusarium circinatum is a pathogen causing serious post-planting mortality of Pinus patula seedlings in southern Africa. Containerized planting stock that is asymptomatic but associated with F. circinatum in the nursery is thought to be the cause of this problem. The aim of this study was to determine if re-use of seedling containers could be a source of inoculum resulting in asymptomatic planting stock and increased post-planting mortality of Pinus patula. Two experiments were conducted in successive years comparing nursery cull of symptomatic seedlings, seedling growth, association of F. circinatum with asymptomatic seedlings and post-planting mortality for crops raised in re-used containers, with and without sanitation, and factory new containers. Each experiment consisted of a nursery production trial followed by out-planting into pots to assess post-planting mortality. Our results show that re-use of containers without sanitation increases the cull of symptomatic seedlings, incidence of F. circinatum associated with asymptomatic seedlings and post-planting mortality compared to the re-use of containers after steam sanitation or factory new containers. Growth of asymptomatic seedlings was unaffected by container treatment or association with F. circinatum and in the absence of wilt symptoms the root system did not exhibit typical discolouration. Watering frequency did not influence post-planting mortality in pots. The comparison of two open-pollinated seed mixes of P. patula that, based on seedling stem inoculation screening, represented susceptible and tolerant material did not show differences in nursery cull or post-planting mortality. This work demonstrated that natural contamination of re-used containers can be a primary source of inoculum producing asymptomatic seedlings associated with F. circinatum that will succumb to the pathogen after field planting. The process of seedling infection, apparent latent infection in the seedling and expression of disease after planting needs greater understanding to improve nursery hygiene measures to control this disease.

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“…shown not to result in persistent post-planting infection or mortality (Smith et al 1965, Dumroese et al 1993b, Axelrood et al 1998.…”

Section: Discussionmentioning

confidence: 99%

Re-use of seedling containers andFusarium circinatumassociation with asymptomaticPinus patulaplanting stock

Morris¹,

Fourie²,

Greyling³

et al. 2014

Southern Forests: a Journal of Forest Science

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“…For example, depending upon the outplanting site, the percentage survival of Scots pine and Norway spruce seedlings has varied from 40 to 85% (SAKSA et al 1990;RIKALA 1992RIKALA , 1994. (DUMROESE et al 1993). Despite this, no studies have been made in Finland to determine the effect of nursery-acquired diseases on conifer seedling mortality after outplanting.…”

Section: Introductionmentioning

confidence: 99%

“…Despite this, no studies have been made in Finland to determine the effect of nursery-acquired diseases on conifer seedling mortality after outplanting. Studies made in the USA and Canada showed that mortality of outplanted seedlings, which had acquired root rot in the nursery, varied depending on the pathogen and the symptoms which were present at outplanting (HANSEN et al 1980;SAUNDERS et al 1992;DUMROESE et al 1993;BARNARD 1994). For example, the mortality of Douglas fir (Pseudotsuga menziesii (Mirb.)…”

Section: Introductionmentioning

confidence: 99%

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Effect of uninucleate Rhizoctonia on Scots pine and Norway spruce seedlings

Lilja

Rikala

2000

Forest Pathology

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One-year-old container-grown seedlings were planted in spring on clear cut areas: the Norway spruce (Picea abies) on a moist upland site (Myrtillus-type) and Scots pine (Pinus sylvestris) on a dryish upland site (Vaccinium-type). While still in the nursery, half of the seedlings of each species had been inoculated during the previous summer, with a uninucleate Rhizoctonia sp., a root dieback fungus. At outplanting all the seedlings appeared healthy and had a normal apical bud, although the height of the inoculated seedlings was less than that of the uninoculated control seedlings. At the end of the first growing season after planting, the mortality of inoculated Scots pine and Norway spruce seedlings was 25 and 69%, respectively. After two growing seasons the mortality of inoculated seedlings had increased to 38% for Scots pine and 93% for Norway spruce. The mortality of control seedlings after two growing seasons in the forest was 2% for Scots pine and 13% for Norway spruce. After outplanting the annual growth of inoculated seedlings was poor compared with the growth of control seedlings. These results show that, although Rhizoctonia-affected seedlings are alive and green in the nursery, the disease subsequently affects both their survival and growth in the forest.

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“…France, or spruce, Picea spp., in North America (Landis 1989;Sutherland et al 1989;Hamm et al 1990) and Europe (Galaaen and Venn 1979;Perrin and Gomez 1991). Although, there is a substantial amount of information available on Fusarium, Cylindrocarpon and Pythium incidence in containergrown seedlings (Sutherland et al 1989,Unestam et al 1989Liljaet al 1992;Dumroese et al 1993), the prevalence and potential importance of these fungi on asymptomatic container-grown seedlings (Landis 1989) remains largely unknown. Although, there is a substantial amount of information available on Fusarium, Cylindrocarpon and Pythium incidence in containergrown seedlings (Sutherland et al 1989,Unestam et al 1989Liljaet al 1992;Dumroese et al 1993), the prevalence and potential importance of these fungi on asymptomatic container-grown seedlings (Landis 1989) remains largely unknown.…”

Section: Introductionmentioning

confidence: 99%

Prevalence and incidence of the root-inhabiting fungi, Fusarium, Cylindrocarpon and Pythium, on container-grown Douglas-fir and spruce seedlings in British Columbia

Kope¹,

Axelrood

Sutherland

et al. 1996

New Forest

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Application.Species of Fusarium, Cylindrocarpon or Pythium were readily isolated from the roots and growth medium of container-grown Douglas-fir and spruce seedlings. Differences in their occurrence varied with nursery, but not consistently with conifer species, indicating that cultural practices which alter conditions such as growth medium moisture and temperature can influence their prevalence.Abstract. Surveys were made at the end of the 1990 and 1991 growing seasons for rootinhabiting fungi in the genera Fusarium, Cylindrocarpon and Pythium from the roots of one year-old container-grown Douglas-fir and spruce seedlings grown under greenhouse conditions. In the 1990 survey of four nurseries, it was found that 61-97% of both Douglas-fir and spruce roots were colonized with Fusarium, Cylindrocarpon or Pythium. There were significantly @ 5 0.05) more Douglas-fir roots than spruce roots colonized by Fusarium at all nurseries, however, there were significantly (p 5 0.05) more spruce roots than Douglas-fir roots colonized by Cylindrocarpon and Pythium. Root colonization of Douglas-fir and spruce by the three fungal genera during 1991 varied from 042% at three nurseries, however, only at a south coastal nursery was there significantly (p 5 0.05) more spruce than Douglas-fir roots colonized by Cylindrocarpon. Significantly more seedlings were infected in 1990 than in 1991. In 1991, there were few significant differences between Douglas-fir and spruce, in the percentage of seedlings with colonized roots and in the percentage of growth medium colonized by the fungi. However, there were significant differences between nurseries.

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Fusarium root infection of container-grown Douglas-fir: effect on survival and growth of outplanted seedlings and persistence of the pathogen

Cited by 8 publications

References 6 publications

Re-use of seedling containers andFusarium circinatumassociation with asymptomaticPinus patulaplanting stock

Re-use of seedling containers andFusarium circinatumassociation with asymptomaticPinus patulaplanting stock

Effect of uninucleate Rhizoctonia on Scots pine and Norway spruce seedlings

Prevalence and incidence of the root-inhabiting fungi, Fusarium, Cylindrocarpon and Pythium, on container-grown Douglas-fir and spruce seedlings in British Columbia

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