In this section:
Bacterial diseases
The bacteria Pseudomonas syringae was detected in grapevines in spring 2000 in the Adelaide Hills region of South Australia, 35 Km East of Adelaide and in the Southern Vales, 30Km south of Adelaide.
Initially a few small dark angular spots (Fig. 1) develop on the leaves, occasionally coalescing (Fig. 2) and causing the leaves to senesce. The infected leaves usually occurred on the lower part (Fig.3) of the vine with occasional yellowing (Fig.4) of the leaf blade. No symptoms were observed on the young fruit, but on one occasion where vines had not been sprayed with copper, some lesions were observed on the stems, petioles and bunch rachis. This disease has been found on Verdelho, Merlot, Chardonnay, Shiraz and Cabernet Sauvignon in the Adelaide hills and the Southern Vales area.
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Fig. 1 Small dark angular sports developing on the leaves. |
Fig. 2 Coalescing causing leaves to senesce. |
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Fig. 3 Infected leaves usually occur on the lower part of the leaf. |
Fig.4 Occasional yellowing of the infected leaf blade. |
This disease is not recognised as a serious problem in grapes, and the first recording appears to be from Argentina in 1968 (Klingner et al 1976). It has so far only been observed in wet springs such as 2000, 2001 and 2005. Bacteria usually require a point of entry into plant tissue and commonly infect through natural openings and wounds. The Argentinian investigators found that leaf infection could occur in wet humid conditions without wounding of the leaf, whereas stems etc required prior wounding for infection to occur. At this stage there appears to be no loss of crop or detrimental effects to the vine apart from some minor leaf loss.
Bacterial diseases are controlled with copper sprays applied as protectants, which will prevent infection and spread of the disease, but will not eradicate it.
Reference: Klinger, A.E., Palleroni, N.J. and Pontis, R.E. (1976) Isolation of Pseudomonas syringae from lesions on Vitis vinifera. Phytopath. Z., 86: 107-116.
No other bacterial diseases are known to occur in South Australia.
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First report of Pseudomonas syringae on grapevines in South Australia (2002) Article published in Australasian Plant Pathology 31(4):421-2
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Two New Diseases of Grapes reported in South Australia 2001. (PDF). Poster presented at Conference.
