An outbreak of the leaf curl plum aphid—Anuraphis helichrysi Ka1t.—occurred in 1953 in Placer County, where a considerable acreage of plums was severely attacked. The aphid—in California for many years but not as a pest of major importance—curls the leaves of the tree in early spring, and new leaf growth is tightly curled during the early summer. As a result of the leaf damage, fruit does not properly develop, and shoot growth is severely stunted.

The above progress report is based on Research Project No. 806.