108 DEPARTMENT OF AGRICULTURE. [Pub. Doc. 



scale. In most cases where this scale was found, the infested 

 plants were so few that they were destroyed. The practice of 

 destroying infested plants, together with the spraying and par- 

 asites of this scale, have greatly reduced the annual infestations 

 in the nurseries, and each year finds conditions improved. A 

 small amount of oyster-shell scale was found, principally on 

 lilacs, willows and poplars. This scale is very common and 

 widespread, and at the same time difficult to combat. It dif- 

 fers from the San Jose scale in that it passes the winter as 

 eggs under the scale. These eggs hatch about the middle of 

 June, and spraying at this time with a contact poison of sum- 

 mer strength is the most effective remedy. These insects must 

 be hit with the spray if they are to be killed, and because of 

 the dense foliage in June it is a very difficult job to do thor- 

 oughly. Several authorities claim that spraying with lime- 

 sulphur in the winter, or preferably in the early spring just 

 before the buds open, is very effective. The lime-sulphur seems 

 to loosen the scales from the bark so that they are more exposed 

 to their enemies or are even sometimes blown away. 



Satin Moth. 

 A new insect in this country, the satin moth, was discovered 

 in Medford in 1920. The moth is closely related to the gypsy 

 moth, and, probably on account of some of its similar habits, 

 was able to become firmly established before being discovered. 

 So far this insect has been found only on willows and poplars, 

 and European writers record it as feeding chiefly on these trees. 

 In Massachusetts the satin moth is known to be in 63 towns, 

 and probably a careful survey would show it to be in many 

 more. The moth appears in July and lays its eggs in clusters 

 on the bark and leaves of trees, although sometimes they are 

 found on stones or even on the ground. The eggs hatch in a 

 few days, but the young feed very little in the late summer and 

 fall. With the approach of cold weather they spin a web in a 

 crevice of the bark, where they pass the winter. It is very 

 difficult to observe them in this stage, as the web is very small 

 and the color closely resembles that of the bark. The insect 

 is in this stage during the period when the fall and spring 

 shipments of nursery stock are made, and a very careful in- 



