throughout California, in parts of Arizona and Utah, and, since 
1951, in a number of eastern States. The Colorado potato beetle 
spread along the Atlantic coast as a relatively new pest of 
tomatoes. Contre] measures are fairly satisfactory except for 
lesf miners. The total loss to tomatoes caused by insects is 
net know. 
Ornamental Plants and Shade Trees 
(Table 8) 
Ornamental Plants 
Insect. control in greenhouses has attained a new level of effi- 
ciency since shout 19146. Most pests that formerly seriously 
injured greenhouse crops are now controlled with the modern pesti- 
cides. In the colder parts of the country insects that do not 
survive outdoors heve almost. disappesred fron greenhouses. Some 
of these are the carnation erhid, crescent-marked lily aphid, 
orchid thrips, orchid weevil, greenhouse thrips, Surinam roach, 
tomato pinworm, greenhouse leaf tier, soft scale, citrus mealybug, 
and Mexicen mealybuge Those pests that survive outdoors continually 
reinfest. greenhouses and cause some losses. Examples of this greup 
are spider mites, the cyclamen mite, leaf rollers, cutworms, the 
onion thrips, garden centipece, rese anhid, green peach aphid, 
melon aphid, potato arhid, leafhoppers, spittle bugs, tarnished 
plant bug, rose scale, and leaf miners. The spider mites and the 
garden centipede have heen particularly troublesome. 
In 1930 the losses caused by insects and related pests to green- 
house flowers and ornamentals in Illinois were estimatad to total 
avout 15 percent (Ill. Nat. Hist. Survey, Ent. Ser. Cir. 12). This 
estimate was accepted for many years ag typical of the greenhouse 
industry. During the past. few years the lesses have been in the 
neighborhood of 1 or 2 percent. In 1938 it was estimated that. 
insect control cost about 5 cents per square foot. Although cost 
of production has more than doubled, the cost. of controlling 
greenhouse pests has prebably remained about the same. 
An outstanding example of the reduction in losses to greenhouse 
ercps is that to greenhouse roses due to spider mites and associated 
insects. Prior to 1946 the annual loss was estimated at approximately 
10 percent, but since then it. has been almost negligible. The annual 
loss for the period 19h2=51 was about $1,647,000, or 5 percent. 
However, some strains of spider mites are already showing some re= 
sistance to the recommended contre] measures. 
Shade Trees 
In 1938 it was estimated that insect. damage to shade trees plus 
the cost. of controlling such insects amounted to $87,000,000 
anruaily. For the period 1912-51 the losses, on the basis of a 
cest of $10 ver tree for replacement alore, are roughly estimated 
