13 
undesirable. The results with Bliss Triumph were not clear-cut but 
showed a similar trend, whereas there was no significant off-flavor in 
the other two varieties. 
Insecticide residues on cucumber fruits following field applications 
of lindane and gamma BHC are discussed on page 17. 
Methoxychlor 
Methoxychlor proved to be one of the least effective materials against 
the pickleworm. Inadequate control resulted from the use of a 5-percent 
dust in 1948 (table 3) and in 1949 (table 4), a 2.5-percent impregnated 
dust in 1949 (table 3), a 10-percent dust in 1950 and 1951 (table 3), a 
0.181-percent suspension spray in 1949, and a 0.189-percent emulsion 
spray in 1949 (table 3). Methoxychlor was inferior to lindane in every 
comparison and usually proved inferior to cryolite. Methoxychlor was 
of considerable value in the control of the melonworm in 1948 and 1949 
(data not shown in tables). This material did not reduce the melon aphid 
infestation in 1951 (table 5), but on methoxychlor-treated plants the 
aphid population was lower than on plants receiving several other in- 
secticides and was no higher than that on untreated plants. Methoxy- 
chlor caused slight to moderate chlorosis of cucumber plants, but this 
injury did not appreciably affect yields. Methoxychlor residues are 
discussed on pa-ge 17. 
Nicotine 
Nicotine was used as an additive to control the melon aphid and to 
increase the degree of pickleworm control given by another insecticide. 
A cryolite-nicotine dust held the melon aphid in check in 1948 and 1949, 
but there was an increase in the infestation when cryolite was used alone. 
Nicotine was of significant value against the pickleworm when used with 
cryolite in 1949 and tended to be so in 1950 (table 3). However, it was 
of no significant value against the pickleworm when used with cryolite 
or rotenone in 1948 (table 3), or when added to rotenone, sabadilla, or 
pyrethrum in 1950 or to sabadilla and allethrin in 1951 (table 3). 
Dusts containing 1 percent of nicotine and 4 percent of either poly- 
ethylene glycol (600) monolaurate or bis(p-chlorophenyl) sulfide^/ were 
ineffective against the pickleworm on squash and on cucumbers (table 3) 
in 1951. Cucumber plants receiving these dusts had significantly higher 
melon aphid infestations than did untreated plants (table 5). The first 
mixture caused slight injury, and the second mixture caused severe 
injury and a reduction in yield. A dust containing 0.5 percent of 
2/ These mixtures were supplied by the Bureau of Agricultural and 
Industrial Chemistry. 
