8 
Bulletin 84. 
The disease was recovered in pure cultures from these apri¬ 
cot twigs in which blight had been artificially produced and 
apples inoculated with this material developed typical cases of 
pear blight. (Fig. 2). 
The results of these experiments prove that pear blight may 
attack apricot twigs and fruit and observations show that the 
disease may do a considerable amount of damage. While this 
apricot blight has not yet assumed alarming proportions, yet 
there is a possibility of its becoming a common disease. It has 
been found in several Colorado orchards and an apricot disease 
has been reported from Utah, which is probably due to the same 
cause. Blighted twigs were also found on Primus simonii trees 
which were also thought to be caused by an attack of pear blight. 
REMEDIES. 
Since this disease has been proven to be due to attacks of 
pear blight, the logical method of treatment would appear to be 
the suppression of this disease in apple and pear trees. With pear 
and apple orchards free from blight there would probably be no 
apricot blight. There is little probability at present, however, of 
ever attaining this ideal condition, but much can be done to hold 
the disease in check if all orchardists will unite in following the 
best treatment that is now known. This consists in cutting out 
all blighted limbs after the growing season is over, as in late fall 
or any time during the winter. 
It is now definitely known that the germs of pear blight live 
over winter in occasional diseased limbs. The germs in such 
limbs become active in the spring with the growth of the tree 
and cause a thick fluid to ooze from the diseased bark. This juice 
is swarming with blight germs and because it is slightly sweet, 
bees and other insects are frequently attracted to it. That bees 
do carry blight germs in particles of this sticky juice that may 
accidently stick to their bodies was proven by Mr. Waite of the 
Department of Agriculture. Then when visiting flowers in their 
search for nectar or pollen it is easy to conceive how these parti¬ 
cles may become dislodged from the bees’ bodies and fall into the 
nectar in the blossom. Mr. Waite also proved that this does 
take place as he found pear blight germs growing in nectar in 
pear flowers. Thus the pear blossoms become sources of infection 
and the disease spreads rapidly or “like a fire,” from which 
expression the term “fire blight” is derived, as hundreds of insects 
visit flower after flower. 
Just how many of the twigs become infected has not been 
satisfactorily explained, but in the light of our present knowledge 
