March 2006. Pineapple growing is a new agribusiness amongst the Amerindian communities in Guyana with a ready market for organic fruit. The pineaples are grown in the forest areas after slashing and burning the forest cover, and the plants have been doing well until recently when the farmers started complaining of a problem. After 6???8 months they start wilting and dying as shown. The leaves lose their green color and start drying from the tips, wilt and ultimately the whole plant dies. When uprooted the middle part is often rotten and smelly. No insect pests (and nematodes) were found associated with this problem.
In the fields, surveyed the damage is high (25???40% of plants), but farmers’ estimates are higher and this is the reason why the communities are worried. Is it possible to identify the problem and suggestion control.
There were two suggestions:
- Pineapple heart rot caused by Phytophthora. Type ‘Pineapple heart rot’ into an Internet browser to get more information on this disorder.
- A mite, possibily Steneotarsonemus. This was reported from Samoa causing similar symptoms. The mite is very small and found at the base of the leaves, by pulling them out. It is associated with reddish-brown lesions and the mites occur around the edge of these. Look at some younger leaves to see if this is the problem.
The CABI Plant Clinic sent a long description of the Phytophthora problem:
Phytopthora heart rot usually affects the younger leaves first, which fail to elongate, and turn chlorotic. The inner leaves (or terminal whorl) are also easy to pull out. A lot of secondary bacterial is associated with this disease problem, which may account for the putrid odour that you describe. Erwinia chrysanthemi also causes heart rot, although leaves start to bloat and turn an olive colour, which is different from the symptoms described. The problem is unlikely to be this. More details are needed on the field conditions, especially rainfall.