3 - 
It is believed that the mite is at present so widely distributed in 
California on petunia, nightshade, and Jimsonweed that tomatoes can- 
not be safely grown in that State without the protection of insecticides. 
These native host plants live over winter in California and survive in 
protected locations even during periods of heavy frosts. Tomato fields 
cannot be isolated sufficiently to prevent infestation. It seems likely 
that the mites are spread by wind to tomato from these host plants. 
Tomato fields not treated with insecticides may not be seriously dam- 
aged every year, but they probably will be infested, and if the weather 
is favorable damage may occur every season. 
Control 
Sulfur dust is the standard remedy for the tomato russet mite. 
Experiments with various control methods have been reported by Bailey 
and Keifer (1), Hoerner (3), Michelbacher et al. (9), Wilcox and 
Elmore (12), and Wilcox and Howland (13). Recent laboratory tests 
(Tuft and Anderson 11) and field tests (Wilcox and Howland 14) indicate 
that a number of the new pesticides are effective. 
The authors have obtained good control with 2-percent parathion, 
2-percent EPN, 5-percent chlordane, 2.5-percent methyl parathion, 
and 20-percent toxaphene dusts. Limited tests indicate that these in- 
secticides are also effective in sprays. However, since sulfur is effec- 
tive and the other materials present greater hazards when used on 
tomatoes, none of them have been recommended for use against this 
mite. 
Excellent control is obtained by dusting the plants with sulfur. Three 
applications are made 2 weeks apart, the first when the fruits of the 
main crop begin to set. A dust containing 50 percent of finely ground 
(325-mesh) dusting sulfur is used at 30 pounds per acre. It may be 
applied in mixtures that also contain 10 percent of either DDT or TDE 
for the control of the tomato fruitworm and other insects. A 25 -percent 
sulfur dust is effective if this schedule is carefully followed. A sulfur 
dust of any strength can usually be applied to transplants without injury, 
but greater strengths may injure small plants less than 6 inches high. 
The tomato russet mite has also been controlled by the addition of 10 
pounds of wettable sulfur per acre to sprays applied for control of other 
pests on tomatoes. 
Sulfur residues must be completely removed before the tomatoes 
are canned. In California sulfur dust was first used on tomatoes with 
considerable caution, as some canners prohibited its use and others 
only permitted 25-percent sulfur to be used. In 1943 the canning com- 
panies had evidence that in ordinary tin cans 1 to 2 p. p. m. of sulfur 
caused bluish iridescent streaks in the tin, at 5 p. p.m. bluish streaks 
were observed in the tin and hydrogen sulfide odor, and at 15 to 20 p.p. 
