100 Farmers’ Bulletin 1169. 
(3) Trees breaking, tops sickly, shredded boring dust in piles on ground 
beneath trees; borer work under bark close to ground__~___-----------~ 
Cottonwood borer, p. 66. 
(4) Smaller twigs wilting, strings of frass dangling from holes in bark, 
worm in burrows vi¥id reddish white, greenish beneath____-_-------___ 
Carpenter worm, p. 69. 
(5) Girdled twigs hanging on trees, or lying on ground below trees____--- 
Twig girdler, p. 71. 
Sap suckers, scale insects. 
Young bark more or less covered with brown or gray, elongate, more or 
less curved, snell-like bodies, readily raised with knife point or finger | 
TRL LS  Ce Se Ss Ree oe ee ee ee eee ee Oyster-shell scale, Me Tit 
Sap sucker, gall-maker. 
Leaves bearing prominent swelling on stem and dropping prematurely___ 
Poplar leaf-stem gall-aphis, p. 89. 
SYCAMORE. 
Leaf chewer. 
(1) Holes in leaves with spindle-shaped bags near by___Bagworm, p. 31- 
(2) White frothlike egg masses on tree trunk; leaves more or less eaten 
by yellow caterpillars with black and red hair -pencils on back___-____ 
White-marked tussock moth, p. 41. 
Sap sucker, bug. 
Leaves off color in spots or entirely ; underside shelters colonies of slow- 
moving, lacelike bugs and their young________ Sycamore lace bug, p. T4. 
TULIP TREE! 
Sap sucker, aphid. 
Leaves discolored, dropping, with numerous aphids on underside, sticky 
With HONeCYGeW. Leek = as eRe ee ee eee eee Tulip-tree aphis, p. 85. 
Sap sucker, scale insect. 
Sickly, blackened branches beset with vivid gray or brown, rather large, 
high Scales: Sa 2 ee Tulip-tree soft scale, p. 80. 
WALNUT. 
Leaf chewer. : 
Leaves being eaten by gregariously feeding caterpillars which, when full 
grown, are black, covered with dirty gray hairs, and nearly 2 inches 
long: 22.20 SS NS eee een nee ts Seek ees Walwut caterpillar, p. 46. 
WILLOW. 
See Poplar, p. 99. 
O 
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