"Plum pockets is another fungal disease that can infect the
Japanese-type plums. Infected
trees will produce abnormally large misshapened, bladder-like fruit
with thick, spongy
flesh. The centre of the infected fruit is hollow due to failure of
the young seed to
develop. The best way to describe the fruit is that it looks like
large pea pods. Infections
also occur in April as the buds swell and bud scales separate. A
spring fungicide
application prior to bud swell will control this disease. The
fungicide thiram 75WP @
6.75 kg/ha is recommended for commercial plantings with Japanese plum
varieties.
Lime sulfur can also be used for those persons that have only a few
plum trees."

From:
http://www.gov.ns.ca/nsaf/elibrary/a...d/980331oo.htm

I hope this helps. Sorry I lost the post to reply to.
--
Cheers,
Loki [ Brevity is the soul of wit. W.Shakespeare ]