28 
I began my studies on the insect pests of the blackberry in the early 
part of the present year, before yet the canes had begun to leaf out, and 
found that all the pests infested cane or root. 
One of the chief pests is the well-known Agrilus rujicollis, or red- 
necked blackberry cane-borer. Its life history has been worked out by 
others, and I have nothing of any importance to add. The well-known 
galls usually indicate the position of the borer, and how to get rid of it 
is the question. I say the galls usually indicate the position of the 
borer, because, though there can be no gall without a borer, we can 
have a borer without a gall. If a gall be split the length of the cane 
it will be seen that the wood is not involved in the gall growth, but 
only the bark. The insects emerge from the canes in early summer, 
May 25 to July 10, the month of June being the time of greatest abun- 
dance. The egg is laid by the female at the base of a leaf stalk, and 
I believe it is not thrust into the tissue, but is simply laid at the base 
of the stalk or in the bud there starting. It was not until late in July 
that any larve were found. The first sign of their presence was a dead 
bud at the leaf axil, and where the stem was carefully examined al- 
most every dead bud showed traces of having been eaten into, the 
minute and very slender young larva being found under the bark 
near by. 
Usually they run up the main shoot; but where laterals have become 
well developed, they often go into these, especially where more than 
one egg was laid in the same place. In neglected fields, often as many 
as three eggs may be found at a single point, and five leaf axils may be 
infested on a single stalk. The young larva bures upward in a cork- 
screw channel in the sap wood, as much in the bark as in the wood, 
until early August. Some are at that period only one-fourth of an inch 
long and almost nothing in diameter, while others are half an inch in 
length and reasonably stout. Sometimes a larva will make only two or 
three long circles around the cane and then, while yet minute, will 
pierce the cane and get into the pith. Where this is done, no visible 
gall forms. Others, however, and usually those in large, stout canes, 
will circle the stalk half a dozen times or more in succession, the girdles 
not more than one-eighth of an inch apart. The first trace of a gall I 
found in early August, when a slight ridge appears over every larval 
gallery, so that the course of the borer is perfectly traceable on a smooth 
stem. As the cane grows the sawdust and excrement in the galleries 
seem to swell and enlarge and also to destroy the vitality of the tis- 
sues around it, until, instead of the girdlings becoming smaller, they 
really become more prominent, and the abnormal growth of tissue con- 
tinues. In some cases, as stated, no galls appear; but this is somc- 
what exceptional. In raspberry I have not found the galls, while bor- 
ers have been found not rarely. This indicates that some of the exempt. 
varieties of blackberries may simply form no galls. [am the more 
inclined to believe this, because I have seen beetles in no small num- 
