North American Fruit Explorers mailing list at ibiblio

[Ray Kaminski <rjkaminski@charter.net>]

Located in North East Wisconsin zone 4-5.  About 15 years ago I planted  9 
various types of pear trees both standard and dwarf.  They were producing 
nice crops and one day a neighbor brought a friend over to get some scion 
wood from me.  Unknown to me, he had used his pruners on stock that was 
infected with stony pit virus. Stony Pit  deforms fruit and makes them 
cat-faced, crooked and they look like some one hit them with a baseball bat 
when they were small.  The fruit is not eatable as it is hard, gritty and 
solid rock in the deformity.  While pruning that year I advertently spread 
it to my entire pear tree crop.  The cure for that virus is to remove your 
trees!!!  That is one heart breaking job when you have had good success so 
far but I did it.
    Replanted with new ones and most went into new ground although some 
went very close to the old locations (holes). Did research on what might be 
cause etc. and found that virus is spread by grafting and pruning.
  Bought new pruners, protective gloves and anything else that I thought 
might be helpful in stopping the spread of the virus.   I used 1 part 
bleach to two parts water along with a brass brush to clean any particles 
on the pruners and cleaned  meticulously after each tree.  You have to 
prune in order to keep the tress in good shape as well as any dead or dying 
branches, so not-pruning is not an option.  There are other orchards with 
this virus within a mile of mine.  Needless to say, it did show up on all 
the trees that bore this summer. One of the trees that is a beautiful pear, 
is the Rescue  which has large rose colored fruit and about 80 per cent of 
the fruit was infected.  The Flemish Beauty had about 50 per cent infected 
and some varieties were 100 per cent infected.
  Pears being one of my favorite fruits, I started 8 more trees about 500 
feet away from this patch this fall and will not prune  on these till they 
bear and see what results I have.
  According to what I could learn  bees or root growth have not been known 
to spread it and only by pruning or grafting.
  Does anyone have any suggestions on containing this virus and also what 
is a fruit virus?  Could not find any info on it.
  Started with 10 fruit trees and now up to 96, strictly as a hobby.
  Each apple tree has 4 varieties on it, try to keep a branch going in 
each direction.  Never used tags on trees, only log it on paper, then put 
it in the computer and all records are easy to keep with all the pertinent 
info like type, date, year ,where from,  type of graft etc.  The best 
teacher probably is experience but  I wish someone would of told me long 
time ago to graft varieties together that blossom and are good 
companions.  Being in that golden age group am running out of time to be 
planting too many more.
Due to hard spring frost this year the crop was light but fruit was bigger 
and when less on a tree it seems bigger, juicier and sweeter.
Any comments, help, ideas of cure would be greatly appreciated.