STATE PLANT BOARD 
j February l$Uh E-613 
United States Department of Agriculture 
Agricultural Research Administration 
Bureau of Entomology and Plant Quarantine 
MOT-A 
THE C0H2R0L 0? THE TWO-SPOTTED MITE - ^ OH LIRA. BEANS U CAlDTOBHIA 
LS^ 
By John C. Elmore, Division of 
Truck Crop and Garden Insect Investigation! 
The damage caused by the two- spotted mite to lima beans in 
Orange and Los Angeles Counties, Calif., since 19Ul, has made control 
measures necessary. Sulfur has long been recognized as the remedy 
for this pest on cultivated crops, but its application has not al- , 
ways resulted in satisfactory control. Experiments made during 19U3 
to determine vhen and how to apply sulfur to lima beans for mite con- 
trol and to develop supplementary measures of control have led to the 
suggestions given in this circular. These should aid the bean grower 
in California in protecting his beans* 
When to Apply Sulfur 
Lima beans in southern California can be protected from appre- 
ciable mite injury by one or two applications of "conditioned 1 ' dust- 
ing sulfur. The period In which applications are made, with respect 
to crop growth and mite Infestation, is the important factor. It has 
been found that, to be most successful, sulfur should be applied with- 
in a period from Uo to 60 days after planting. The mites do not be- 
come numerous enough to damage the crop until more than Uo days after 
planting. On the other hand, applications need not be made later than 
60 days after planting to protect the plants for the rest of the season. 
The dusting period for beans planted May 1 would be from June 10 to 30 
and for those planted Kay 15 It would be from June 25 to July 15. Dur- 
ing these periods the plants are small enough to permit dusting equip- 
ment to pass through without plant damage and to make control possible 
by use of a moderate amount of sulfur per acre. Experimental plots 
dusted 30 days after planting became heavily infested before harvest- 
time. Plots dusted 67 to 77 days after planting required a larger 
amount of sulfur per acre, and the plants were damaged because they 
were too large to allow the dusting equipment to pass through freely. 
1/ The name "two-spotted mite" is proposed for Tetranychus 
blmaculatus Harvey, one of the several species that have been known 
as common red spiders, or epider mites. 
2/ The author wishes to acknowledge the cooperation and as- 
sistance of the Departments of Agriculture of Orange and Los Angeles 
Counties in the field work done on this problem. 
