Fire Blicuit or Pilars, Apples, Quinces, Etc. 



159 



cispccially favorable conditions the parasite may also live over in blighted 

 shoots or twigs. With the rise of sap and the increased temperature of 

 spring the bacteria in these hold-over cankers become active, multiply 

 and spread into the adjoining healthy bark. Here they increase to such 

 an extent that on warm, rainy days they ooze from the lenticels and 

 cracks in the diseased bark as thick syrupy drops of a dirty white or 

 brown color (Fig. 16). This oozing from hold-over cankers usually 

 takes place first, about the time the blossoms are opening. Wasps 

 and flies visit these cankers to sip the 

 sweet ooze, and becoming smeared with 

 it from head to toe (Fig. 13) fly away 

 to the opening blossoms. Here som.e 

 of the bacteria of which the ooze is 

 composed are left behind in the nectar 

 of the flower. They multiply rapidly 

 in the sweet solution and the next bee 

 visitor unwittingly carries the fatal 

 germs to all the succeeding blossoms 

 that are visited. The bacteria pene- 

 trate the tender tissues of the flower 

 and within nine or ten days blossom 

 clusters here and there over the trees 

 begin to turn black and wither, fol- 

 lowed shortly by the wilting and black- 

 ening of the leaves on the spur. Blos- 

 som Blight (Fig. 6) is the result. 

 During rainy weather the bacteria ooze 

 from these blighted blossoms and are 



carried by plant lice, leaf hoppers and Fig. 1$.— Blighted stub resulting ]rom 



other sucking insects to the tips of introduction of bacteria on the prun- 



, . 'ng saw. 



the twigs that are now growmg rap- 

 idly; here, in sucking the sap the insect introduces the bacteria into 

 the tender tissues where Ihey multiply rapidly, producing in a few days 

 the characteristic ''Twig Blight" (Fig. 7). Sometimes the bacteria are 

 introduced by insects into the green fruit, where they find an abundance 

 of proper food and moisture and soon the fruit shows the symptoms 

 of the disease. The loss from Fruit Blight (Fig. 8) is frequently quite 

 heavy, though it is seldom associated in the mind ,of the grower 

 with the Twig Blight. The bacteria commonly work their way down 

 the s-pur to the limb, spread into the surrounding bark and form 

 cankers (Fig. 6). Where watersprouts or shoots are allowed to grow 



