71 
turn pale and become stunted, and eventually the whole plant succumbs 
unless remedies are applied. Cuttini^s and young- rooted plants are 
especially susceptible to injury, and more particularly in spring. 
These mites injure by suction, slowly reducing the vitality of plants 
until in time their functions are more or less deranged. Among 
ornamental plants that are much affected are violet, rose, clematis, 
minuet, pink, fuchsia, pelargonium, godetia, passillora, feverfew, 
thunbergia, verbena, heliotrope, moon- 
fiower, calla, smilax, and Easter lily; 
while of other crops, beets, beans, sage, 
tomato, eggplant, pepper, cucumber, 
squash, cowpea, hops, and berries of 
various kinds are attacked. As a rule 
this species is not especially harmful to 
the sugar beet but is quite destructive 
at times in fields of other crops; for ex- 
ample, to beans, which have been badly 
injured in South Carolina in recent 
years. 
.Remedies, — This red spider is resistant 
to "gassing" or fumigation, either with 
tobacco or hydrocyanic-acid gas. It is, 
however, peculiarly susceptible to sul- 
phur, a sovereign remedj^ for mites in 
general. Flowers of sulphur mixed with water at the rate of 1 ounce 
to the gallon and sprayed over the plants is of great value in its eradi- 
cation; or the sulphur may be combined with a wash, for example, 
with strong soapsuds. 
Potash, fish oil, whale oil, and other soap solutions, resin wash, and 
kerosene-soap emulsion are also valuable, and the addition of sulphur 
increases their effectiveness; but these washes are too strong for some 
delicate plants and are apt to injure them. For violets and similar 
plants, as they occur in greenhouses, no other remedy is used by flor- 
ists generally than frequent syringing or spraying with water or with 
a solution of neutral soap. Directions for the application of the soap 
washes to violet and other greenhouse plants are furnished in Bulletin 
27, new series, of the Division of Entomology (pp. 40-42). 
Fig. 65. — Tetranychus bimaculatun: a, 
adult; b, palpus; c, claws (after Banks, 
Division of Entomology). 
o 
