Symptoms
Pineapple disease is a fungal disease principally affecting sugar cane planting material, but it may also affect the stubble of recently harvested crops. The disease may devastate germination and lead to the replanting of entire fields - a costly exercise in terms of extra time, fuel, fertiliser, planting material, and insecticide. Initial symptoms are an uneven or a complete lack of germination. When setts are dug up and split longitudinally, internal tissues are seen to be discoloured, grading from water-soaked to red to red-black. Rotting starts from the cut ends but becomes more serious when it penetrates through the nodes into the central portion of the sett. The disease tends not to affect the vascular tissue, giving the setts an internal fibrous appearance. Spore production leads to a blackening of internal tissues, particularly in the central pith. In the early stages of the disease, a strong odour similar to over-ripe pineapples is present which gives the disease its name.Establishment of ratoon crops may also be affected. Under certain conditions, the fungus may invade the cut ends of the stubble remaining after harvest and inhibit germination of the buds which normally give rise to the ratoon crop. It is thought that the fungus produces a toxin which may kill the buds or young shoots. This is why, in recently planted crops, germination may occur but the young shoots may die. When shoot root production has occurred, the shoot becomes independent of the planting material and the disease can exert little effect on subsequent growth.

Cause
The casual agent of the disease is Ceratocystis paradoxa, an ascomcete fungus. The fungus resides in the soil; soil populations are favoured by the presence of incorporated sugar cane material. The disease is controlled by the application of fungicide to the cut ends of the planting material, and the use of sound planting material.

Distribution
Pineapple disease occurs throughout the Australian sugar industry. Its incidence is favoured by cool conditions, poor soil preparation, excessively wet or dry soil moisture, poor planting material, and planting too deep.

Assessment of Severity
Timing of inspections
A number of difference causes may lead to poor germination. To correctly diagnose pineapple disease, planting material should be examined as soon as poor germination becomes evident (4-6 weeks after planting). If inspections are left too long, it is impossible to accurately assign a casual agent.

Assessing severity
Pineapple disease (area affected) is recorded infields where part or whole field is replanted due to poor germination caused by the disease.