EPIDEMIOLOGY AND CONTROL OF A SUNFLOWER HEAD ROT IN ISRAEL CAUSED BY RHIZOPUS ARRHIZUS

Injury of the heads was found to be necessary for the infection of sunflower (Helianthus annuus L.) by Rhizopus arrhizus Fischer, identified as the causal agent of a soft rot. Infection did not take place before flowering. Birds visiting the heads in search of seed were implicated in the spread of the disease. The disease was controlled by a single application of Copper 8-quinolinolate.

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Antioxidant systems in sunflower (Helianthus annuus L.) seeds as affected by priming

Seed Science Research ◽

10.1017/s0960258500000040 ◽

2000 ◽

Vol 10 (1) ◽

pp. 35-42 ◽

Cited By ~ 82

Author(s):

Christophe Bailly ◽

Abdelilah Benamar ◽

Françoise Corbineau ◽

Daniel Côme

Keyword(s):

Superoxide Dismutase ◽

Polyethylene Glycol ◽

Beneficial Effect ◽

Helianthus Annuus ◽

Strong Increase ◽

Antioxidant Systems ◽

Seed Vigour ◽

Helianthus Annuus L ◽

Glycol Solution ◽

And Control

AbstractPriming treatment of sunflower (Helianthus annuus L., cv Briosol) seeds for 7 days at 15°C with a polyethylene glycol solution at −2.0 MPa strongly improved their subsequent germination at 15°C on water. This stimulatory effect of priming remained after drying back the seeds at 20°C for 3 days. Malondialdehyde (MDA) and activities of superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) were measured in control unprimed seeds, primed seeds, seeds primed then dried, and after 3 and 6 hours of imbibition of controland dried primed seeds in order to determine whether the cell antioxidant systems were involved in the beneficial effect of priming. The osmotreatment resulted in a strong increase in SOD and CAT activities but did not markedly affect MDA and GR activity. Following the 3 days of drying, MDA increased and the enzyme activities became similar to those measured in dry unprimed seeds, although the stimulatory effect of priming on germination remained. Imbibition of control dry seeds was associated with an increase in MDA and a decrease in CAT and GR activities, whereas reimbibition of dried primed seeds resulted in a decrease in MDA and an increase in SOD, CAT and GR activities. Isoform patterns on native gels showed no difference between treated (priming with or without subsequent drying) and control seeds for SOD (7 isoforms) and GR (5 isoforms), but the osmotreatment did induce a second isoform of CAT. The results obtained indicate that the CAT isoform pattern might be used as an indicato of the priming treatment that promotes germination. Involvement of theantioxidant systems in seed vigour is discussed

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Importance of Coniothyrium minitans in survival of sclerotia of Sclerotinia sclerotiorum in wilted sunflower

Canadian Journal of Botany ◽

10.1139/b77-039 ◽

1977 ◽

Vol 55 (3) ◽

pp. 289-295 ◽

Cited By ~ 46

Author(s):

H. C. Huang

Keyword(s):

Helianthus Annuus ◽

Sclerotinia Sclerotiorum ◽

Growing Season ◽

Root Surface ◽

Causal Agent ◽

Stem Rot ◽

Coniothyrium Minitans ◽

Basal Stem Rot ◽

Helianthus Annuus L ◽

The Relationship

The relationship between Sclerotinia sclerotiorum, causal agent of wilt or basal stem rot of sunflower (Helianthus annuus L.), and its hyperparasite Coniothyrium minitans was investigated in a sunflower field naturally infested with the two organisms. Sclerotia of S. sclerotiorum were collected biweekly from roots and basal stems of wilted plants and analyzed for infection by the hyperparasite. The results showed that C. minitans parasitized and killed the sclerotia produced on the root surface. This hyperparasite continued to parasitize the pathogen inside the root and upwards into the base of the stem, thus infecting the sclerotia produced at these sites. By the end of the growing season, 59%, 76%, and 29% of sclerotia on the root surface, inside the root, and inside the stem, respectively, had been killed by the hyperparasite, while 4%, 9%, and 68% of the sclerotia at these locations were healthy. Death of the rest of the sclerotia was due to organisms other than C. minitans. The data also indicate that C. minitans is more effective in parasitizing sclerotia produced on or inside the root than those produced in the basal stem.

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Rhizopus oryzae Associated with Melanagromyza splendida and Stem Disease of Sunflowers (Helianthus annuus) in California

Plant Health Progress ◽

10.1094/php-rs-14-0042 ◽

2015 ◽

Vol 16 (1) ◽

pp. 39-42 ◽

Cited By ~ 3

Author(s):

Febina M. Mathew ◽

Jarrad R. Prasifka ◽

Stephen D. Gaimari ◽

Li Shi ◽

Samuel G. Markell ◽

...

Keyword(s):

Helianthus Annuus ◽

Seed Production ◽

Geographic Distribution ◽

Sunflower Seed ◽

Rhizopus Oryzae ◽

Causal Agent ◽

Parental Line ◽

Disease Symptoms ◽

Stem Infection ◽

Head Rot

In September 2012, a female parental line in a Yolo Co., California, sunflower seed-production field began displaying external stem symptoms that could not be attributed to any known disease. Symptoms appeared to be associated with tunneling caused by an unidentified insect. Stems were collected, and Rhizopus oryzae (causal agent of Rhizopus head rot) and a minute fly, Melanagromyza splendida, were identified as the causal agent and associated insect, respectively. Further, R. oryzae was isolated from intact fly puparia. All commercial hybrids evaluated in the greenhouse were susceptible to stem infection by R. oryzae isolates. Yield implications and geographic distribution of this novel stem disease are unknown. This is the first report of R. oryzae causing stem disease in sunflowers, and of its association with M. splendida. Accepted for publication 10 January 2015. Published 25 March 2015.

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Rhizopus oryzae as a causal agent of a head rot of sunflowers in Queensland

Australian Journal of Experimental Agriculture ◽

10.1071/ea9770495 ◽

1977 ◽

Vol 17 (86) ◽

pp. 495 ◽

Cited By ~ 2

Author(s):

KJ Middleton

Keyword(s):

Field Experiments ◽

Rhizopus Oryzae ◽

Causal Agent ◽

Disease Development ◽

Atmospheric Humidity ◽

Protective Barrier ◽

Head Rot ◽

And Control ◽

Established Infection

The causal agent of a common head rot of sunflowers in Queensland was isolated and identified as Rhizopus oryzae. Field experiments were conducted to investigate the environmental and host conditions suitable for disease development, and control of the disease by the use of fungicides. The disease occurs in wound inoculated plants when atmospheric humidity is high. Dicloran is capable of restricting established infection, but wound inoculations made after the application of the fungicide avoid the protective barrier and are uninfluenced by it. The possible use of chemicals to control the disease is discussed.

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RELATION OF INFESTATION WITH SUNFLOWER MOTH HOMOEOSOMA ELECTELLUM LARVAE TO THE INCIDENCE OF RHIZOPUS ROT IN SUNFLOWER SEED HEADS

Canadian Journal of Plant Science ◽

10.4141/cjps79-122 ◽

1979 ◽

Vol 59 (3) ◽

pp. 797-801 ◽

Cited By ~ 11

Author(s):

J. M. KLISIEWICZ

Keyword(s):

Helianthus Annuus ◽

Sunflower Seed ◽

Rhizopus Oryzae ◽

Helianthus Annuus L ◽

Head Rot ◽

Sunflower Moth ◽

Homoeosoma Electellum ◽

Rhizopus Rot

Larvae of the moth Homoeosoma electellum (Hulst.) were found consistently in sunflower (Helianthus annuus L.) seed heads affected with Rhizopus rot in California. Both Rhizopus rot and larvae were found in 88% of the rotted heads examined and only Rhizopus rot was evident in 12% of the heads. Head rot developed in 55–100% of the sunflower heads artificially inoculated in the field with both Rhizopus oryzae Went & Brinsen-Geerlings and H. ellectellum larvae and in 5–20% of the heads inoculated only with Rhizopus. Rot did not occur in heads in which only larvae were present. Larvae enhanced infection of the receptacle by Rhizopus through feeding injury. Ingested spores that are viable after passage through the gut of a larva can be spread by larvae into the inner tissues of the sunflower receptacle.

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