14 
COLORADO EXPERIMENT STATION. 
In December, kerosene emulsion and soluble petroleum sprays 
were given egg-covered trees, and the per cent of eggs destroyed at 
time of hatching this spring will be determined. Further experi¬ 
ments for the control of this pest are planned, including a large series 
on contact insecticides to be used this spring. 
WOOLLY APHIS. ( Schizoneura lanigera.) 
Importance —Probably more important to the fruit growers of 
Western Colorado than the green aphis is the woolly aphis of the 
apple. The past season this pest has ranked second only to the cod¬ 
ling moth in destructiveness in the Grand Valley, and has been of 
first importance in other counties of the Western Slope. 
Life History —Many lived through the winter upon the roots 
of the apples, and a few survived the winter upon the branches above 
ground. During the winter of 1905-06 the • temperature at Grand 
Junction, according to the United States Weather Station, did not 
drop as low as the zero point, and the unusually mild winter perhaps 
had much to do in the great abundance of the insect this past summer. 
In May many of the aphids above ground had already secreted 
their woolly coverings of white, and in cases heavily infested the 
water sprouts about the base of the-tree. By the month of July, 
countless myriads of them were to be seen crawling over all parts 
of the tree and fruit, as well as upon the ground through the orch¬ 
ards. Winged ones were noted first at Fruita September 6. 
Parasites —Parasites have done some service in helping to keep 
in control the pest, but have not been abundant enough to reduce 
the number of insects to a point below injury. Lace wing and syr- 
phus-fly larvae, as well as adults and larvae of lady beetles, have been 
most prominent in preying upon this aphis. Some observations upon 
the habits and life history of these parasites have been made. 
Injury —Roots and tops were attacked throughout the season, the 
twigs being sometimes entirely coated with the woolly secretion cov¬ 
ering the bodies of the insects. Such infested twigs were greatly 
dwarfed, the bark on the twigs caused to split and grow in a gnarled 
and misshapen form. The "honey dew” secretion from the insects 
in some cases coated over the peeling of the fruit itself, leaving the 
surface so sticky and discolored that apples were disgusting in ap¬ 
pearance and most unpleasant to handle. Grafts and top-worked 
trees suffered most heavily in the spring, and their injury continued 
through the summer. 
So thick were the insects upon the branches that apple pickers 
working in the trees had their clothing covered with crushed bodies 
and the white secretion of the insect. 
Roots about the crown of the trees were gnarled and knotted, 
resulting in the dwarfing of the trees, the production of undersized 
fruit, and, in exaggerated cases, the outright destruction of the trees 
themselves. 
Experiments in Progress —Summer sprays, as with the green 
aphis, where the infestation was so severe and so general through 
the orchards, proved of small practical value. 
