SYMPTOMATOLOGY AND THE OCCURRENCE OF MYCOPLASMA-LIKE ORGANISMS DISEASE OF STATICE (LIMONIUM-SINUATUM) IN ALBERTA, CANADA

New symptoms of witches' broom and axillary shoots in the phylloid flo ral stems of annual statice (Limonium sinuatum (L.) Mill.), caused by mycoplasma-like organisms (MLOs), were found in Alberta in August 199 1. This is the first report of MLOs of statice in the province. MLOs r anged in size from 0.12-0.56 x 0.12-0.51 mum (mean = 0.29 x 0.33 mum). The MLO bodies were mostly spherical, lacked cell walls and were surr ounded by single membranes. Six cultivars of statice grown in three lo cations of the province were surveyed for tolerance to MLOs. The cv. ' Golden Coast' showed the most tolerance to the disease and had the low est percentage of flower loss. The average incidence of leaf reddening (LR), stunting, flower bunching and witches' broom (WB), and phyllody were 32.2, 11.7, 15.8, and 8.6%, respectively. The percentage of stun ting and WB symptoms increased slowly with time and on a much smaller scale than those of LR. The number and dry weight of flowers of diseas ed plants were significantly reduced relative to those of healthy ones . MLOs induced distortion of chloroplasts and caused an average of 18. 7% loss of flower production in late summer. The results indicated tha t the economic impact of this MLOs disease on the floral production of statice could be significant in Alberta.