The occurrence of toxic levels of lithium in southern California citrus has been found to be more widespread than previously reported. Approximately 5 per cent of the total acreage shows symptoms of toxicity attributed at least in part to excess lithium. Some of the most severely affected acreages are on newly developed desert areas using locally developed well water with a high lithium content. A survey of the lithium content of irrigation waters of California is in progress.

The above progress report is based on Research Project No. 1025-B.