346 Plums and Plum Culture 



caterpillars are abundant. Early and thorough spray- 

 ing will give practical immunity from this serious pest. 



Cankerworms. — These small caterpillars, or meas- 

 uring-worms, about an inch long, hatch in the 

 spring from eggs laid in the fall (fall cankerworm) or 

 spring (spring cankerworm). They appear on the 

 trees with the opening leaves and are easily discovered 

 by jarring a branch, when they come down out of the 

 trees suspended by fine silken cords of their own 

 spinning. Bands on the tree trunks, over which the 

 wingless female moth cannot crawl to lay her eggs, are 

 often recommended as a good means of defense against 

 cankerworms. Such bands should be of sticky tar, 

 cotton or similar material. But really the best treat- 

 ment is thorough spraying with paris green or some 

 similar arsenical poison. This should be applied when 

 the little caterpillars make their first appearance. One 

 spraying is usually enough, unless imperfectly done or 

 unless heavy rains wash off the poison. 



Bud Moth. — The bud moth (Turetocera occllana) f 

 better known as an enemy of the apple, sometimes at- 

 tacks plum trees, especially young trees in the nursery. 

 The larvae eat into the young buds at the time they are 

 opening, usually destroying the young shoot. They 

 also eat the very young leaves. When they are dis- 

 covered soon enough they may be killed by spraying 

 with paris green. The spray really ought to be given 

 just as the buds begin to open; but, unless one suspects 

 an attack in advance, it is seldom possible to be so 

 prompt. If the larvae are discovered at work, how- 

 ever, a spraying should be given at once. 



Red Spider. — This common pest of greenhouses 

 and conservatories rarely attacks plum trees. The 

 mite or spider itself is so minute that it can hardly be 

 seen, and one becomes aware of its presence first by 



