30 THE BEAN THEIPS. 
On September 18, 1911, he wrote : 
This tlirips is very abundant in alfalfa fields at this time of year, the larva? 
being present on the older alfalfa and the adults present on the younger shoots 
and leaves. Many leaves, after being badly scarred by the thrips, wilt and fall 
off, so that the damage is soon very great. It seems rather strange that this 
thrips should become so very abundant in the fall of the year and Euthrips 
tritici, the other important alfalfa thrips, should decrease in numbers and 
that in the spring of the year just the opposite should be the case. 
COTTON. 
September 22, 1910, Mr. Wildermuth wrote : 
This thrips was found damaging cotton about 11 miles southeast of EI 
Centro, Cal. The cotton was only damaged in one corner of the field, and it 
happens that fresh alfalfa is being stacked close to this corner. 
September 28 a field of cotton east of Imperial had a strip through the center 
of the field damaged by this thrips. September 30 numerous fields on the east 
side of the valley were being damaged by this pest. The leaves were dead and 
rusty looking aud the plants in bad condition. The damage was not as great as 
if the work had begun earlier in the season, but was at that time very great. 
October 11 several cotton fields at Holtville, on the east side of the valley, 
were examined. A great many fields showed considerable injury. The leaves 
were eaten and turned a sickly yellowish or brown, many often being curled. 
A field on the Young ranch was as badly damaged as any seen, and this field 
lay alongside an alfalfa field. Three other fields on the same ranch showed 
very little damage. The former field was of a late planting. This thrips has 
caused much more damage to cotton than was anticipated, and if it should 
begin its work early in the season it might prove extremely destructive. Be- 
cause of this, as well as other still better reasons, cotton should be planted as 
early as possible in the spring. 
In November, 1911, Mr. Wildermuth wrote: 
Mr. Tackard and cotton growers throughout the valley report but little injury 
to cotton by this thrips this year. I found only two specimens of larva? myself, 
and a few adults. It would seem as if the damage to cotton comes when cotton 
follows alfalfa. This year, there being but little alfalfa land put ^o cotton 
and more cotton following cotton, the damage was not so noticeable. 
WILD PLANTS. 
Of all food plants of this insect the wild spiny lettuce (Lactuca 
scariola) seems to be preferred, at least in the vicinity of Los Angeles. 
From early spring, when this plant comes up, until it dies down in 
the fall, it is usually badly infested by thrips. Many cases have been 
observed where other food plants, such as beans, etc, in the same field 
were only slightly infested, while the spiny lettuce near by was so 
badly attacked that many plants were dead. Furthermore, this weed 
is one of the commonest in the country, occurring abundantly in un- 
cultivated or even in badly cultivated fields. In addition it grows 
up in dense clumps in all fence rows and roadsides, and the rights 
of way of the different railroads are densely packed by this plant. 
