'TolDaccc flea "beetles E, .paryigla and 2. cucumeris ,- are controlled oy 
cube or derris dusts containing sterilized tobacco dust as the diluent. — 
United States Department of Agriculture, Bureau of Entomology and Plant 
Q,uarantine ( 39^ ) in 1937. 
White (Ul3) in I936 and again (UlU) in I937 advised thct the most 
satisfactory control of flea beetles attacking tobacco is a derris or cube 
dust containing 1 percent of rotenone. These dusts are obtained "by diluting 
derris or cube powder to the desired strength with a clay diluent. The foil 
ing dosages of dust are recoramended for each application: Tor plant "beds 
1/2 pound per 100 square yards, a,pplications to "be repeated every k days unt 
control is o"btained. For newly set plants, 3 ^o 5 pounds per acre, applica- 
-..tions to "be repeated every U days until control is obtained. For the gro^-^- 
ing Ijohacco crop, 8 to 10 pounds per acre, depending on the size of the 
plants, applications to be repeated every 7 days until control is o"btained. 
F. S. Chamherlin (fk ) in 193^ reported that experiments and observ- 
ations have indicated that finely ground and sterilized to"bacco dust is the 
most satisfactory diluent for cu"be or derris when applied to shade-grown 
to'bacco in combating the to"bacco flea beetle. The addition of clay to the 
customary cuhe- or derris-tobacco-dust mixture used for com"ba.ting the to"bacc 
flea "beetle apparently did not improve its dusting qualities when applied 
with rotary hand-operated dusters. It appeared that the use of a dust mix- 
ture containing 1 percent of rotenone, ^-rith 75 percent of tobacco dust and 
25 percent of finely ground G-eorgia clay as a diluent, on shade-grown tobac- 
eo--' under favora"ble weather conditions at the rate of 6 pounds per acre, 
did not leave conspicuous residues on the cured tobacco leaves. Heavier ap- 
plications, however, did leave conspicuous deposits on the cured product. 
In general, these experim.ents demonstrated that the addition of finely grour 
clay to the derris- or cube-to"bacco-dust mixture did not result in any ap- 
precia'ble improvement in the finished dust mixture and may cause a permanent 
white residue to remain oii the treated leaves. 
Chamberlin (jG) later reported in I93S thcit results of recent exporimer 
designed to determine the duration of the toxicity of a cuhe-dust mixture 
containing 1 percent of rotenone to the to'bacco flea "beetle on shade-grown 
to'bacco have shown that the toxicity of this dust mixture to the insect 
decreases very rapidly on shade-gro'wn to"buCco. In the presence of the most 
favorable \reeth r conditions the effectiveness of a light applica.tion of 
the cuhe-dust mixture is limited to approximately 3 days "but apparently the 
toxic action o.ccuring on the third day after application is relatively 
slight. Showers evidently remove much of the cu'be-dust mixture from tobaccc 
foj-iage and render such applications ineffective. It is "believed that this 
mechanical loss hy the action of rain is one of the most important factors 
limiting the effectiveness of cube-dust mixture for flea "beetle control in 
Florida. Cu'be-dust mixtures applied to shade-grown tobacco "by the "drift" 
method when the foliage is moist with dew appeared to 'be more offoctivo 
against the flea "boctlo than vrhcn applied to dry foliage. The a"bovo results 
wore obtained and conclusions drawn from oxporimonts wherein the method of 
proccduro consisted of confining a definite number of toba.cco flea beetles 
with loaf discs cut from the troo.tcd foliage at vorious intervals and deter- 
mining the percentage of the resulting flea beetle mortality. 
Gory (88) in I93S issued recomiacndrtions based on the report of the 
Tobacco Insect Council, for the control of tobacco insects. 
