108 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 
examples were noted by Mr. Zimmer on an adjoining block of apple 
of the Jersey Sweet and Early Harvest varieties. The varieties of 
peach most injured were Crawford’s Late, Mountain Rose, and 
Old Mixon. The varieties Crosby, Stump the World, and Georgia 
Bell were least injured. The ground planted had been in wheat in 
1909 and was planted to peach for the first time in the spring of 
1910. The buds used were obtained partly from a bearing orchard, 
but largely from nursery trees in an adjacent block, but in which no 
injury had been noted. 
A similar outbreak was also reported as occurring in a near-by 
nursery. 
A prominent nursery company in Ohio, writing of this trouble, 
states, under date of October 30, 1911: 
We have been bothered with the thrips in peach trees for 15 or 20 years. This year 
and last very bad. Some years very little. This year first time ever bothered much on 
peach seedlings. If we can get peach buds 3 or 4 feet before this pest begins, we can 
make very good trees. 
A Maryland nursery firm gives their experience as follows, under 
date of October 24, 1911: 
We have had lots of trouble and loss caused by the ‘‘setback ” on peach seedlings and 
also on peach buds. In 1910 we saw nosigns of it, but this year (1911) it caused us a good 
deal of extra expense. When the trees are stung by this insect in the terminal bud 
during the summer and when the trees are about 18 to 24 inches tall, it causes them to 
stop growing in the top and put out a lot of side or lateral branches, and if not attended 
to they will be worthless. The past summer we kept a gang of men going over our 
peach blocks and cutting or heading in the side branches in order to throw the growth 
to the terminal and make them start a second growth. In this way by constant work 
we got our trees to start to grow and the most of them finally outgrew the trouble. We 
knew no other remedy than to cut the side branches back 2 or 3 inches. We notice it 
is much worse in some places even in the same field than others. 
Prof. Waite’s careful observations, and those of Messrs. Johnson, 
Phillips, and others, indicate clearly that the Tarsonemus waiter is 
the cause of the so-called ‘‘stop-back”’ affection of peach nursery 
stock. It may also be true that injury practically identical im effect 
on the trees is caused by thrips, as stated by Dr. Smith and Prof. 
Alwood. Young thrips larve, principally Huthrips tritici, are very 
commonly found in the tender growing tips of various kinds of 
vegetation, and are especially common in peach nursery trees. In 
blocks of trees infested with the mite, the thrips larvee have been 
found by the writer in great abundance, but never, so far as could be 
determined, killing the tips of the shoots. The writer is inclined to 
the belief that the injury in Ohio, New Jersey, and Virginia (as shown 
by Phillips) is due to the Tarsonemus, its small size, agility, and 
habits contributing to its oversight. 
Any injury to the growing tip of a peach shoot, as by plant-bugs, 
would naturally produce a similar effect in causing the cessation of 
growth and the development of lateral shoots, but the comparative 
