FALL NUMBER 19 
to expect that the same insect pests which are present in both 
of these localities should also be present in the Valley. Such is 
largely the case and we find about the same scale insects and 
mites present as in both Florida and California. The Florida 
red scale is supposed to be the most injurious scale present. It 
seems to thrive in the hot dry climate. Next in importance is 
the California red (this may be dictyospermum). This scale 
was observed in a grove, the trees of which were purchased in 
California, in great abundance. In fact this scale had nearly 
killed this entire grove which was only saved from total destruc- 
tion by the use of oil emulsion two or three times last winter. 
The chaff scale, P. pergandii, does great damage to the twigs 
and trunk and no doubt is the third most injurious scale insect. 
The long scale, L. gloverii, is the fourth in importance and does 
much more damage than the purple scale. The purple scale is 
also present but I presume the sun is too hot for its proper de- 
velopment in great numbers. I understand the citrus white fly 
is present at Brownsville but I did not see it myself. 
The citrus rust mite is present in the greatest abundance in the 
Valley. It often becomes so abundant that the limbs turn blue 
and the leaves take on a brown color and, in many cases, do not - 
reach normal size. The fruit on several groves was badly rus- 
seted and in many cases the living mites and eggs were present 
on the fruit in countless numbers. 
Even though rust mites are extremely abundant they can be 
very easily controlled by means of dusting with sulphur. Owing 
to the infrequency of rains the sulphur would remain on the 
foliage for long periods of time and sufficient to kill rust mites 
would no doubt be present until a rain came and washed it from 
the trees. 
Entomogenous fungi. None of the entomogenous fungi at- 
tacking scale insects were observed. Neither the county agents 
nor Mr. E. W. Halstead had ever seen them in the Valley excep- 
ting on nursery stock when received. No doubt these fungi have 
been introduced many thousands of times and owing to the 
adverse climatic conditions have never established themselves. 
I did not find out if our Florida fungus on rust mites was pres- 
ent. Neither the citrus red spider nor the six-spotted mite, T. 
sexmaculatus, were observed. Another red spider, however, 
of a greenish tinge with dark spots on its back was observed 
at McAllen. I am of the opinion that this is the same red spider 
