The
              Report
No. 91: Disease management and new varieties may boost exports of wildflowers


The full report

This is a summary of a full report Varietal development and disease management of Ixodia Achillaeoides for cut flower produc- tion published by RIRDC (Pub.No.00/ 186,DAS-45A)by Gail Barth,South Australian Research and Development Institute.Phone:08 8303 9400,Fax:08 8303 9424, Email:barth.gail@saugov.sa.gov.au

The report is available in hardcopy (under wildflowers) or downloadable from this site.

Exports of higher quality Ixodia daisy wildflowers are expected following a varietal improvement and disease management project funded by the Rural Industries Research and Development Corporation (RIRDC).

The project sought to extend the wildflower ’s harvest period,provide new products for dried and fresh flower markets and improve the quality of the wildflower ’s characteristics –including stem length,floral appearance,post harvest life and disease resistance.

Gail Barth and Barbara Hall of the South Australian Research and Development Institute,reported the Ixodia achillaeoides (Ixodia daisy )crop was previously bush harvested but for the past 20 years also has been increasingly cultivated.

Strong demand exists for dried Ixodia blooms for both export and domestic markets.The daisy is diverse in form, appearance and geographic origins and there are many unassessed varieties and seedlings under cultivation.

But production of varieties with unknown performance records has led to poor quality control,lack of confidence by growers in farming practices,and with increasing cultivation,a range of disease problems have emerged seriously affecting or restricting production of Ixodia.

These diseases require identification, pathogenicity testing and control measures, to allow Ixodia production to proceed as a profitable venture.

The Research

The main objective was to increase the amount and the quality of Ixodia daisy produced for export markets by overcoming the varietal and production-based problems limiting commercial uptake and expansion.

To achieve this,a varietal improvement and disease management program was commenced which aimed to provide better varieties of Ixodia to industry.

Varietal improvement

The varietal improvement program involved:

Disease study

The disease study involved surveying Ixodia diseases in commercial plantings and native populations.

The most serious losses of the daisy in commercial plantings are from the disease Verticillium dahlia e –more serious where levels of plant pathogenic nematodes are high.

Phytophthora cinnamomi and Phytophthora cryptogea –serious diseases of most Australian native flower crops –also were a problem.

Table 1.1 Summary of attributes of major geographic forms of Ixodia achillaeoides .
 
ORIGIN
OTHER NAMES
SA
BLOOM PERIOD
FLOWER SIZE
OTHER CHARACTERISTICS
Central Mt. Lofty Ranges Adelaide Hills  SA Jan-Feb 8-10 mm Thick winged stems, tall bushes, quality blooms, flat terminal clusters or sprays
Lower Mt Lofty Ranges Deep CreekSA SA Dec 10-12 mm Intermediate in form and blooming period. Often well branched bush
Kangaroo Is. SA Jan-Feb 6-8mm.,

>12mm

 Variable forms: fine foliaged small to medium flowers, dwarfs
South-East SA Nov 12-15 mm Early, high yield first year, short-lived
Yorke/Eyre Peninsula SA Dec-Jan 5-7 mm Fine stems and foliage, small bushes or dwarfs: potential for pot plants and landscape use
Nelson Glenelg River NP Vic Nov-Dec 12-15 mm Variable, open sprays and flat topped, Medium stems, high yielding, good quality
Donovans SA Jan-Feb 12-15 mm Late form, similar to Nelson varieties
Portland/ Mt. Richmond Vic Dec >15mm Largest flowers, wide leaves and thick stems. Short stem length
Grampians Grampians NP Vic Feb-Mar 5-10mm Variable petal forms, small to med bushes, fine stems Attractive flower forms
Lower Grampians NP Vic Feb-Mar 3-8 mm Smallest flower forms, distinct thin stems and leaves
Anglesea, Vic Vic Feb 8-10mm Pink buds, potential colour variants

The Results

Field performance trial results demonstrated outstanding cut flower forms originate in two distinct geographic regions of South Australia and Victoria.Varieties from the Adelaide Hills (SA)and Nelson (Victoria)districts were capable of producing highest yielding plants, best adapted to cultivation conditions.

Yield in stem length classes was determined for each assessed variety along with flower and bunch characteristics,wastage and postharvest performance,particularly to identify varieties with outstanding potential for fresh flower development.

Growth patterns of five varieties representing distinct geographic forms were monitored fortnightly over 18 months.

This established differences in growth between forms and varieties that would impact on management practices.Quality characteristics of cultivated Ixodia were defined to allow for continued development and selection of improved forms to support economical production.

Results of post harvest assessment trials suggest that Ixodia varieties suited for marketing as a fresh product require vase life above10 days,stem lengths above 40 cm and freedom from stem blackening in water.

The average vase life of all the plants assessed in the program was 11.3 days with the longest lasting flowers in the range of 15-17 days.

Geographic origin proved important,as forms designated Deep Creek and Mt Richmond performed significantly better in keeping-quality trials than all other forms.

Currently,the early Nelson varieties have been most frequently grown for fresh flower markets but these new results indicate that as a whole these varieties have performed poorly in keeping quality.There are no known controls for these diseases other than fumigation.

Disease research

The most serious losses of Ixodia in commercial plantings were found to be from the disease Verticillium dahlia e,which is more serious where levels of plant pathogenic nematodes are high.

All 58 cultivars tested in this program were susceptible.There are no known controls for these diseases other than fumigation.

Susceptibility to Phytophthora cinnamomi and Phytophthora cryptogea varied among cultivars with significant differences in sensitivity relating to geographic classes.These results were used in selecting parent varieties in the breeding program.

The report recommended managing phytophthora in Ixodia by isolating infections through removing plants and drenching the site and neighbouring plants with a fungicide such as Fongari ®.The remaining crop should then be treated using a regime combining applications of Ridomil Go ®or granules initially and maintenance sprays of Foli-R-Fos ®as a preventative treatment.

The planting area should be rotated with a non- susceptible crop in the next planting cycle.

Leaf diseases including powdery mildew and botrytis were found to be increasingly a problem in crowded plantings where overhead irrigation was used or where there was a heavy weed problem.

Nine treatments were evaluated for controlling powdery mildew and a wettable sulphur compound was found to be the most effective.

Examples of dried ixodia flowers and bunches: i.capitula from 4 varieties ranging in diameter from 3-12 mm ii.clusters of dried flowers arranged in corymbs and showing differences in centre colour iii.50 and 60 cm bunches of terminally flowered stems.


 

Table 2.8.Comparison of two years data (1998/99 and 1999/00)of stem classes and total yield (TH)for Varieties 60-67 at the Lenswood site. Data is presented as fresh weight in grams.
 
   
Year 1 Weight (gr)
  
Year 2 Weight (gr)
  
Variety
Geo
40cm
50cm
TH
40cm
50cm
TH
60
N
342 bcd
626 b
968 bc
390 b
620 abc
1009 bc
61
N
560 b
1129 a
1689 a
661 b
30 c
683 c
62
KI
1023 a
518 b
1541 a
688 b
451 bc
1139 bc
63
N
429 bc
715 b
1144 ab
1620 a
840 ab
2477 a
64
E
250 cd
0
250 d
758 b
0
790 bc
65
N
178 d
454 b
631 bcd
      
66
H
410 bc
225 b
430 cd
410 b
1175 a
1585 b
67
G
403 bc
191 b
594 bcd
543 b
740 ab
970 bc

Summary

The main research outcome was to identify varieties of Ixodia daisy available for commercialisation with known flowering, cultivation and postharvest characteristics and which have been assessed by growers and wholesalers for market performance.

Performance standards were determined by continually evaluating selected varieties in replicated field trials supported by laboratory and greenhouse investigations.

Meetings with growers groups and trial shipments were used to evaluate and predict market performance.

Superior varieties have now been identified for commercialisation and in partnership with RIRDC and industry,the best methods of protecting and disseminating varieties for the benefit of industry will be developed.

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