Causal Agents of Silver Top and Other Types of Damage to Grass Seed Crops

Arnott, D. A.; Bergis, I.

doi:10.4039/ent99660-6

Cited by 8 publications

(9 citation statements)

References 8 publications

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“…Berkenkamp and Meeres (1975) reported similar results from their study. Schurr and Bean (1963) and Arnott and Bergis (1967) supported the insect vector theory and emphasised that silvertop was effectively eliminated in stands through the use of insecticides in contrast with the results from applying acaricides.…”

Section: Resultsmentioning

confidence: 96%

“…The importance of silvertop for different grass species is reported by Kůdela et al (2012) (Table 1). Schurr et al (1963) and Arnott et al (1967) supported the insect vector theory and demostrated that symptoms of silvertop were eliminated by insecticide, while elimination by acaricide was not proved. Cagaš and Rotrekl (2014, personal communication) provided similar results.…”

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confidence: 76%

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First report of Fusarium poae associated with and/or causing silvertop on loloid-type Festulolium in the Czech Republic

Nedĕlník¹,

Strejčková²,

Sabolová³

et al. 2015

Plant Prot. Sci.

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Nedělník J., Strejčková M., Sabolová T., Cagaš B., Both Z., Palicová J., Hortová B. (2015): First report of Fusarium poae associated with and/or causing silvertop on loloid-type Festulolium in the Czech Republic. Plant Protect. Sci., 51: 136-140.Silvertop is a serious disease of grasses, and severe infestations cause a great deal of damage every year (particularly to seed producers). Inflorescences of infected plants dry prematurely and are sterile. The genera Festuca, Poa, Agrostis, Trisetum, and Cynosurus are the most frequent hosts of this disease, which has newly been reported in a loloid-type intergeneric Festulolium hybrid. The disease was also observed in the genus Lolium, with only rare previous description. The suspicion that Fusarium poae is the causal agent of severe silvertop was confirmed, and the pathogen was morphologically described and confirmed by molecular analysis. The meadow plant bug (Leptopterna dolabrata) may be a vector transferring the pathogen to plants, although a direct pathogen transfer was not demonstrated. Grass colonisation by the pathogen therefore apparently occurs after plant tissues injury by sucking of the meadow plant bug.

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Section: Resultsmentioning

confidence: 96%

mentioning

confidence: 76%

First report of Fusarium poae associated with and/or causing silvertop on loloid-type Festulolium in the Czech Republic

Nedĕlník¹,

Strejčková²,

Sabolová³

et al. 2015

Plant Prot. Sci.

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“…Stenodema spp. are also known to cause silver top (Arnott and Bergis 1967) and were collected in low numbers on the Rathdrum Prairie and the in Grand Ronde Valley, but were absent from central Oregon samples. Silver top was not a problem in the Þelds sampled, but has been reported to occur in Kentucky bluegrass in the Northwest.…”

Section: Discussionmentioning

confidence: 99%

Association of Insects and Ergot (<I>Claviceps purpurea</I>) in Kentucky Bluegrass Seed Production Fields

Butler¹,

Alderman²,

Hammond³

et al. 2001

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Insects in Kentucky bluegrass seed production fields in Oregon, Idaho, and Washington were sampled just before harvest and their association with ergot conidia of Claviceps purpurea Fr. (Tul.) was evaluated during 1996-1998. A diversity of insects was observed at all three locations. The most abundant beneficial insects collected with sweep nets were Nysium spp., Nabis spp., ichneumonid wasps, and Hippodamia spp. The cranberry girdler, Chrysoteuchia topiaria (Zeller), was the only important pest on grass seed collected by sweep net. Numbers of aphids such as Sitobion avenae (F.), cicadellids and thrips such as Anaphothrips spp. and Aptinothrips spp. that were collected with all aphid sampler were below economic thresholds. Other insect groups occurred in low numbers. Noctuid moths collected in universal blacklight traps included nine species of cutworms and armyworms. Protogrotis obscura (B. & McD.) was the most common cutworm species and was present in all fields. The moth Chortodes rufostrigata (Pack.) previously reported only from wet meadows in northeast and south central Oregon was found in Kentucky bluegrass fields in central Oregon, suggesting that irrigated Kentucky bluegrass seed production fields may simulate a montane meadow habitat. Conidia of C. purpurea were found on a diversity of insects, including moths, flies, leafhoppers, and thrips. Up to 100% of moths and 75% of flies collected from some fields carried conidia of C. purpurea. No correlation between ergot honeydew present in a field and number of insects with conidia of C. purpurea was detected.

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“…Previous studies have reported over 30 species of arthropods associated with silvertop (Peterson and Vea 1971, Gagné and Gagnon 1984, Bürges et al 1993. Insects that feed on stems by puncturing sheaths and damaging stems at the base of culms, notably plant bugs in the families Miridae and Capsidae, are most frequently considered to be the principal causes of silvertop (Hardison 1959, Arnott and Bergis 1967, Kamm 1979, Bürges et al 1993, 1995, while thrips, mites, and leafhoppers also have been associated with this type of injury (Holmes et al 1961, Kamm 1971, Suski 1984, Chang et al 1998. The hypothesis that arthropods are the causal agent is supported by studies showing that spring application of insecticide decreased silvertop incidence (Okuda 1988, Chang et al 1997, Bragg et al 2002.…”

Section: Introductionmentioning

confidence: 99%

Dimethoate insecticide application seldom reduces silvertop incidence in grass seed fields on the Canadian prairies

Soroka¹,

Gossen²

2022

Can. J. Plant Sci.

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Many arthropods have been reported (but none confirmed) as causal agents of sterile seed heads in perennial grass seed fields, known as silvertop or white head. Field studies to identify the arthropods that cause silvertop were conducted in five perennial grass species at seven sites in Saskatchewan, Canada over several years. The effect timing of insecticide application in spring – early, mid or late – and of post-harvest residue management – mowing, close mowing with straw removed (scalping), and burning – on subsequent arthropod populations, silvertop incidence and seed yield were assessed. Samples of grass tillers and sweep net collections were taken regularly, and the arthropods collected were identified to family level and counted. Arthropod populations from sweep samples varied among sites and dates in number and taxon composition, but no arthropod assemblage was consistently associated with silvertop in any grass species. Thrips were the most numerous arthropods on tillers at all sites. Insecticide application often temporarily reduced arthropod populations, but reduced silvertop incidence at only 1 of 15 site-years, and increased seed yield at only 1 of 17 site-years. Scalping or burning did not reduce silvertop incidence but often increased healthy seed head numbers and seed yield relative to mowing, the standard treatment. The majority of Kentucky bluegrass fields had extremely low seed yields unrelated to silvertop or arthropod levels. This extensive study, across a range of grass species and management regimes, provides strong support for the conclusion based on previous work that arthropod pests are not the sole cause of silvertop.

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Causal Agents of Silver Top and Other Types of Damage to Grass Seed Crops

Cited by 8 publications

References 8 publications

First report of Fusarium poae associated with and/or causing silvertop on loloid-type Festulolium in the Czech Republic

First report of Fusarium poae associated with and/or causing silvertop on loloid-type Festulolium in the Czech Republic

Association of Insects and Ergot (<I>Claviceps purpurea</I>) in Kentucky Bluegrass Seed Production Fields

Dimethoate insecticide application seldom reduces silvertop incidence in grass seed fields on the Canadian prairies

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