Fiji leaf gall (previously Fiji disease) is a plant disease that affects sugarcanes. This disease caused an epidemic in the sugarcane industry between the 1970s-90s combined with lush crops embedded with high nitrogen content and warm humid weather. In Australia and Fiji, this virus caused irreparable damage to commercial sugarcane. In the Bundaberg district of Queensland in 1979, over 70 million plants were present with the disease. It is spread by a small insect known as planthopper (Perkinsiella saccharicida Kirk) and by planting infected seed cane. The planthopper nymph can acquire the virus from feeding on the phloem of an infected plant. The virus multiplies in the planthopper and can be pivotal during the summer months when populations are at their highest.
To diagnose the symptoms of Fiji leaf gall, locating the formation of galls on the underside of the leaf blade and midrib must be observed. If you run a fingernail over a suspected gall, you can feel the raised galls which appear to be green or white in colour. Fiji leaf gall can cause profuse tillering, severe stunting, and even the death of plants. The leaves also appear darker green. When infected stalks are planted, severe stunting can occur and as the growing point often dies, this causes side-shoots on stalks.
Since the last known crop disease was sighted in the Central Queensland region, over 32,000 crop inspections have been undertaken. To prevent this disease, an onslaught of management techniques have been used which include termination of heavily-infested crops, quarantine, rogueing of diseased stools, varietal resistance, and using disease-free plant sources. Roguing is a method that has been done at regular intervals since the disease can continue irrespective of roguing practices, therefore the only feasible method of control may be plough-out.
Several districts have used these measures as they have been proven to be highly effective in reducing and detecting the disease. Approved seed plots are available in all districts. Plots must be positioned in low-risk areas to prevent the spread of the disease by the planthoppers. However, the most important aspect for controlling the disease is disease-free seeds.
Read more from our sources below!
Source:
FAO – Review of sugarcane Fiji leaf gall disease in Australia and the declaration of pest freedom in Central Queensland.
Sugar Research Australia – Fiji leaf gall
Plantwise – Fiji disease of sugarcane
Lucidcentral -Sugarcane Fiji disease
