Cause Colletotrichum gloeosporioides (sexual: Glomerella cingulata), a fungus that survives on infected plants and plant debris. Some reports indicate the fungus may be seedborne. Wet weather and overhead irrigation favor the disease. Spores are produced in abundance within lesions. 'Gold Coast' is very susceptible.
Symptoms The crown and base of leaves decays; however, many leaves may still look healthy. Soon plants wilt, become somewhat yellow, and die. Sometimes symptoms may be on only one side of the plant. The tap root is unaffected until the crown completely rots. Symptoms often occur before flowering.
The fungus also can cause spots on leaves, flower stems, and flowers. Spots begin as small circular lesions. Tan to brown irregularly shaped spots with a yellow halo may also develop. Spotting may be so severe that flower stalks are girdled.
- Remove and destroy infected plants.
- Avoid overhead irrigation, or water such that plants are not wet for extended periods of time.
- Banner MAXX at 5 to 8 fl oz/100 gal water. Although not listed for this pest, it may be effective. Group 3 fungicide. 12-hr reentry.
- Bonide Fung-onil Multi-purpose Fungicide at 2.25 teaspoons/gal water. Group M5 fungicide. H
- Daconil Weather Stik at 1.38 pints/100 gal water. Flowers may blacken. Group M5 fungicide. 12-hr reentry.
- Mancozeb-based products. Group M3 fungicides. 24-hr reentry.
- Fore 80 WP at 1.5 lb/100 gal water plus a spreader-sticker.
- Protect DF at 1 to 2 lb/100 gal water plus 2 to 4 oz spreader-sticker.
- Ortho MAX Garden Disease Control at 2 teaspoons/gal water. H
- Spectro 90 WDG at 1 to 2 lb/100 gal water. Group 1 + M5 fungicide. 12-hr reentry.
- Thiophanate-methyl-based products. Tank-mix or alternate with fungicides that have a different mode of action. Fungi resistant to these chemicals have been found in other areas of the world. Group 1 fungicide. 12-hr reentry.
- Cleary's 3336 EG at 12 to 16 oz/100 gal water.
- OHP 6672 4.5 F at 10.75 to 20 fl oz/100 gal water.
Reference Engelhard, A.W., Howard, C.M., and Wilfret, G.J. 1972. A new crown rot, leaf and scape spot disease of statice (Limonium sinuatum) incited by Colletotrichum sp. Plant Disease Reporter 56:894-895.