Shasta Daisy Research Articles

Weed Control in Container-grown Herbaceous Perennials

Tolerance of transplanted black-eyed Susan (Rudbeckia hirta var. pulcherrima Farw.), lanceleaf coreopsis (Coreopsis lanceolata L.), shasta daisy (Chrysanthemum × superbum Bergmans ex. J. Ingram), purple coneflower [Echinacea purpurea (L.) Moench.], and blanket flower (Gaillardia aristata Pursh) to preemergence herbicides was evaluated in container trials. Herbicides were applied at the maximum use rate and twice the maximum use rate. Dithiopyr, pendimethalin, and prodiamine provided excellent control of spotted. spurge (Euphorbia maculata L.) and yellow woodsorrel (Oxalis stricta L.) with little injury to the five herbaceous perennials. DCPA, oxadiazon, and metolachlor were tolerated by all treated species, but these chemicals provided lower control of one or both weed species. Oryzalin, isoxaben + trifluralin, and napropamide caused unacceptable injury and shoot fresh-weight reductions in some of the perennials at one or both application rates. Chemical names used: dimethyl 2,3,5,6-tetrachloro-1,4-benzenedicarboxylate (DCPA); S,S-dimethyl 2-(difluoromethyl) -4-(2 -methylpropyl)-6-trifluoromethyl-3,5-pyridinedicarbothioate(dithiopyr);N-[3-(1-ethyl-1-methylpropyl)-5-isoxazolyl]-2,6-dimethoxybenzamide(isoxaben); 2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide(metolachlor);N,N-diethyl-2-(l-naphtha1enenyloxy) propanamide(napropamide);4-(dipropylamino)-3,5-dinitrobenzenesulfonamide (oryzalin);3-[2,4-dichloro-5-(1-methylethoxy)phenyl]-5-(1,1-dimethylethy1)-l,3,4-oxadiazol-2-(3H)-one (oxadiazon); N-(1-ethylpropyl) -3,4-dimethyl-2,6-dinitrobenzamine (pendimethalin); N,N-di-n-propyl-2,4-dinitro-6-(trifluoromethyl)-m-phenylenediamine (prodiamine); 2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)benzamine (trifluralin).

Response of Nine Herbaceous Flowering Perennials to Selected Herbicides

Abstract Nine herbicides registered for use on turf and ornamentals were applied semiannually for 2 years to 9 species of field grown herbaceous flowering perennials. The herbicides used were Balan (benefin), Betasan (bensulide), Dacthal (DCPA), Devrinol (napropamide), Fusilade (fluazifop), Ornamental Herbicide 2 (oxyfluorfen + pendimethalin), Pennant (metolachlor), Poast (sethoxydim), and Ronstar (oxadiazon). The perennials included fernleaf yarrow, shasta daisy, coreopsis, dianthus, daylily, candytuft, red hot poker, statice, and phlox. Betasan produced no visual phytotoxicity. All other treatments, excluding Ornamental Herbicide 2 (OH-2), caused less than 20% injury to all species tested. OH-2 caused 40%, 39%, and 30% injury to daylily, yarrow, and red hot poker, respectively. Economically tolerable (less than 25%) injury was exhibited by phlox and shasta daisy treated with OH-2, by daylily treated with Pennant, and by phlox treated with Ronstar. OH-2 increased flowering of coreopsis and statice by 97% and 235%, respectively, while it reduced plant area of phlox by 53% and flowering of phlox by 34%. Both Pennant and OH-2 reduced flowering of dianthus by nearly 30%.

Regulation of Growth and Flowering in Chrysanthemum × superbum Bergmans1

Abstract Seedlings of Chrysanthemum × superbum shasta daisy varied greatly in their requirements for flowering. Some vegetatively propagated clones of selected seedlings required cold in order to flower, some required long photoperiods, some required both, and some required neither. Flowering bedding plants were produced from seed in 6–8 months.

Control of Acremonium Wilt of Shasta Daisy

CHASE, A. R., and D. E. MUNNECKE. 1980. Control of Acremonium wilt of Shasta daisy. Plant Disease 64:377-379. Shasta daisies (Chrysanthemum maximum) were propagated in vitro using shoot tips (0.5 mm long) from field-grown 'Killian' daisies infected with Acremonium strictum. Viable explants were assayed, and those free from internal fungal and bacterial contaminants were multiplied in vitro. Commercial fumigation of naturally infested fields (sandy loam soil) at the rate of 340 kg per hectare of a 2:1 mixture of methyl bromide and chloropicrin delayed reinfection of pathogen-free plants for as long as 6 mo. Acremonium wilt of Shasta daisy (Chrysanthemum maximum Ram.) was first reported in 1978 (2). Symptoms include vascular browning, chlorosis and necrosis of the lower leaves, wilting, stunting, and overall debilitation of the host. The causal agent, Acremonium strictum W. Gams (3), is a weak pathogen dependent on stress of the host for maximum development in the plant. Elimination of the fungus from the plant Present address of senior author: Agricultural Research Center-Apopka, Route No. 3, Box 580, Apopka, FL 32703.

Septoria leucanthemi . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Septoria leucanthemi . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Chrysanthemum leucanthemum, C. maximum, C. segetum . Also by inoculation on Chrysanthemum parthenium, C. roseum, Tagetes patula, Centaurea cyanus, Achillea ptarmica, Helichrysum sp., Helianthus annuus . DISEASE: Leaf spot of ox-eye daisy ( Chrysanthemum leucanthemum [Leucanthemum vulgare] ), shasta daisy ( C . maximum ) and corn marigold ( C . segetum ). The disease is sometimes referred to as leaf blotch of shasta daisy (Wormald, 1925). Symptoms appear on leaves of all ages and are of two types: dark brown circular or semicircular zonate lesions with a central sunken pale or whitish area surrounded by somewhat elevated concentric markings and measuring 0.5-2 cm wide; shot-hole spot usually appearing during extremely wet conditions, where the central pale depressed area falls off leaving behind spots with abundant pycnidia around the rim of the shot-hole. In severe cases leaves turn yellow and completely wither. GEOGRAPHICAL DISTRIBUTION: Africa (South Africa); Asia (U.S.S.R.); N. and S. America (Canada, U.S.A., Argentina); Europe (Denmark, France, Germany, Great Britain, Italy, Norway, Portugal, Spain, Yugoslavia. (Literature; Herb. IMI). TRANSMISSION: The pathogen may be transmitted by splashing rain drops and by contact. It remains in a viable condition in diseased plant debris and serves as the inoculum for the following year.

光中斷による切花の促成と抑制

This study was designed to secure the effect of light break on prolonging and forcing of the cut flower. For prolonging of short day plant, two varieties (early variety“Yoshino”and late variety“Edo”) of chrysanthemum were selected. The experimental lots of light break are as follows. (1) Lighted from 8p.m. to 9p.m. (2) from 10 p.m. to 11p.m. (3) from 12p.m. to 1a.m. (4) from 2a.m. to 3a.m. (5) from 4a.m. to 5a.m. (6) from 6a.m. to 7p.m. (7) control.The light break treatment was began on August 15 and was ceased on Oct. 10. Some plants from each lot were dissected to observe floral initiation, and flowering date of each of lot was recorded successively.The inhibiting effect was the most remarkable in the 4th lot. For the late variety“Edo”, in the 4th lot the mean flowering date was Dec. 16, while for control that was Nov. 6.For forcing of long day plants, Aster Savatieri and Shasta daisy were selected. In this case, the experimental lots were as follows. (1) Lighted from evening to 9p.m. and from 3a.m. to morning. (2) Lighted from 11p.m. to 12a.m. (3) Lighted from 1a.m. to 2a.m. (4) Lighted all night and (5) control.For aster the result was not clear, but for Shasta daisy forcing effect was observed in relation to the length of lighted time, being not so distinct by light break.

DERMATITIS DUE TO THE BLOSSOM OF GREVILLEA BANKSII

The occasional production of dermatitis venenata by contact with flowering plants has been commented on briefly by several writers. Weber,1in an extensive list of cutaneous irritants, mentioned the following plants as occasional sensitizers: daffodil (Narcissus pseudonarcissus), buttercup (Ranunculus asiaticus), tree of heaven (Ailanthus altissima), gas plant ( [Fraxinella] Dictamnus albus), olive spurge ([Mezereon] Daphne mezereum), catalpa (Catalpa sp.) and pasqueflower (Anemone patens). The list did not specify whether the blossoms or the leaves or both were irritating. Shelmire2discussed dermatitis from flowers and shrubs, remarking that florists and housewives, especially the latter, are naturally the most frequent sufferers from this. The most common skin sensitizers among the flowers and shrubs in his experience were the primose (Primula obconica), painted daisies ([Pyrethrum] Chrysanthemum sp.), feverfew (Chrysanthemum parthenium) and other members of the chrysanthemum family; less frequent offenders were the Shasta daisy, narcissus, tulip, iris, vinca, petunia, verbena, carnation, zinnia,