28 THE BEAN THEIPS. 
OTHER VEGETABLES. 
During the spring and early summer this insect is not noticeable 
on either the sugar or table beets. Late in the summer, however, as 
the wild plants die down, these plants often become badly infested, 
but as the beets have nearly completed their growth little real in- 
jury results. The outside leaves seem to be first infested, showing 
series of minute white spots more or less in chains, where the chloro- 
phyll has been removed, but in badly infested leaves the underside 
becomes white and dried and covered with small black spots, causing 
the leaves to wilt. Mr. Parker wrote from Hamilton City, Cal., 
under date of September 18, 1911, that the injury was apparent in 
almost every field. 
Cabbages and other crucifers are commonly infested by this thrips 
and at times may be seriously injured. On March 27, 1911, cabbages 
in the laboratory yard were slightly infested. Where the}- had fed 
long the underside of the leaf was fall of the silvery-white feeding 
marks of this insect and the tin} 7 black specks of excrement. Cauli- 
flower suffers to the same extent as the less valuable cabbage. 
This insect has also been found feeding quite extensively on let- 
tuce, potato, and tomato. At Hollywood, Cal., in February, 1911, 
it was very abundant on the foliage of pea vines, but the infestation 
did not appear to increase, inrobably because the vines were quite old. 
PEAR. 
Mr. S. W. Foster found pear foliage badly injured on August 31, 
1909, at Martinez, Cal. He wrote: 
The foliage gave the appearance from a distance of having been scalded. 
Close examination showed that the leaves were often injured in large areas on 
either or both surfaces. The larvae, feeding only on these outer surfaces, soon 
cause the blackened areas. 
As the tree has made most of its growth for the season and the fruit crop 
has been harvested, it is hardly probable that this species will prove of serious 
consequence to the growers unless it should get so numerous as to appear in 
numbers early in the season. 
ALFALFA. 
The following field observations on the work of the bean thrips 
on alfalfa and cotton were made by Mr. Wildernruth in the Imperial 
Valley, Cal. : 
August 2. 1910. This thrips does nearly all if not all of its feeding on the 
upper surface ot the leaf. The excrement is arranged in definite rows, often 
semicircular in form, around these eaten spots and makes a very characteristic 
mark [see fig. 9]. The eaten spots later turn yellow and then the alfalfa 
presents a sickly appearance. August 4 I visited several alfalfa fields and all 
were very much injured by this thrips. Scarcely a leaf could be found that 
