6 
to that of the blackhead fireworm, nor has the cranberry there any 
other pest which annually destroys so much as this one. 
The young larvae start to feed on the newly growing tips shortly 
after they hatch, in the months of April and May, and continue 
their work throughout the growing season, attacking in greater or 
less severity the buds, blossoms, and later the berries, injuring 
the berries by boring into them and causing them to shrivel and 
dry and often to fall from the vines. The most noticeable feature 
of the attack of the fireworm during the middle or latter part of 
the summer is the burnt appearance of the vines which results from 
the work of this insect, suggesting the name fireworm. Since the 
terminals are most affected, few if any fruit buds are set when the 
vines are badly infested, and as a result nearly all the crops of the 
current season and of the following year are destroyed by the 
feeding of the larvae during a single season. The vines, while never 
completely killed, are very much stunted and by the end of the 
summer are left stripped of the majority of the leaves. They are 
often brittle, and in the case of long-standing infestation are short 
and scrubby with numerous short and crooked branches as a result 
of being prevented from making a natural terminal growth. From 
this condition they do not usually return to their normal produc- 
tiveness until good control work has been in force for several years. 
NUMBER OF GENERATIONS. 
By rearing the insect from the winter egg stage in an outdoor 
shelter it was found that it passes through two generations and 
sometimes a partial third. For example, the hatching of the winter 
eggs starts the first generation, and the resulting larvae which change 
into pupae and moths also belong to the first generation. 
The eggs that these moths lay start the second generation. Con- 
trary to the behavior of this pest in the East, only about four-fifths 
of these eggs hatched to form a second generation the same season in 
which they were deposited. The remaining one-fifth did not hatch 
until the following spring. 
All the eggs deposited by the moths resulting from the second set 
of individuals are known as the eggs of the third generation. So 
far as is known, in eastern cranberry regions the eggs of this genera- 
tion do not hatch until the following spring. On the Pacific coast, 
however, it was found that about one-third of the eggs of this gen- 
eration hatched late in the summer, forming a third generation of 
larvae. Because of adverse weather conditions toward the latter 
part of the season, none of these larvae developed into pupae and 
moths. This generation is therefore called a partial or incomplete 
generation. 
