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Dusting should be done when there is little or no air movement 
either at night or during the morning before the wind becomes too strong 
to permit thorough coverage of the plants. 
Number and Bate of Applications 
In situations not previously subject to serious mite damage* such 
as localities where alfalfa is not being grown, one application of dust- 
ing sulfur at the rate of 30 pounds per acre. k$ to 50 days after plant- 
ing, is recommended* In localities subject to early or heavy mite in- 
festations, or where there is a possibility of serious mite damage, two 
applications of sulfur should be made, at 30 &&& 50 pounds per acre, re- 
spectively, the first kO to k$ days after planting and the second about 
2 weeks later. The second application need not cover more than 6k mar- 
ginal rows on each side of the field and a border of the same width 
across each end* 
Dusting Equipment 
The most satisfactory dusting machines for lima beans are of the 
row type capable of covering eight rows at a time and mounted on, or pulled 
by, tractors. It is very important to get the dust evenly distributed on 
the under sides of the leaves. This can be done by using dusting machines 
equipped with nozzles to direct the dust to both sides of each row. If 
one outlet per row is used, the dust can be directed to the under sides 
of the leaves with a T nozzle carried between the rows. If two outlets 
per row are used, the nozzles should be so directed that the dust strikes 
the plants from both sides and from below. 2h the case of S-row dusters, 
larger air volume and less friction will be obtained with eight 2- inch 
tubes or outlets than with sixteen 1^-inch tubes. When nozzles or tubes 
become clogged with dust material, they may be cleaned by running a small 
amount of scouring sand through the machine. 
The cost of custom dusting in 19^3 'ranged from $2.50 to $5.00 
per hour for labor and equipment, plus $1.00 to $1.65 per acre for 
sulfur. With 8-row dusters, from 8 to 10 acres were usually dusted 
per hour. This dusting resulted in an increased yield ranging from 
MOO to ^OO pounds in some fields as compared with the yield from un- 
treated areas within the fields. 
Indirect Control 
Any practice that reducee the number of mites on other nearby 
infested plants early in the season will tend to reduce infestation in 
the bean fields. Therefore, the treatment of alfalfa, roadsides, or 
other sources of mite infestations with sulfur early in the season is of 
value. Likewise, the destruction, along roadsides and ditch banks, of 
morning-glory plants and other weede that are infested with the two-spotted 
