« 2 - 



The data for each species are tabulated in tables 1-6 with the cos- 

 pounds arranged in order of descending toxicity . The results with a 

 standard spray are included in each table. 



In the tests against armyworras (table 1) approximately half the com- 

 pounds gave 100 percent kill at £ percent concentration, but at 1 percent 

 all were ineffective. There was no definite effect shown by varying the 

 N-alkyl mono- or di- substitutions in either the formamides or the for- 

 manilides. However, o-chloroformanilide was the most toxic, with the cor- 

 responding meta and para compounds showing much less toxicity. The 2,£- 

 dichloro derivative was less toxic than the ortho compound but more toxic 

 than the meta compound. 



Fumigation tests with 26 of the compounds against the larva® of the 

 bean weevil (table 2) showed the three lowest dialkyl formamides to be 

 the most effective. The higher homologs were ineffective. Branching of 

 the chain also had an adverse effect. The ethyl and propyl formamides 

 showed moderate toxicity, and the higher members practically none. Only 

 the o-chloroformanilide showed slight toxicity. The others showed none 

 at all. 



In tests against nymphs of the large milkweed bug (table 3) the higher 

 monoalkyl formamides showed the highest toxicity at 5 and 1 percent. The 

 tert- and dibutyl formamides were also rather toxic. About one-third of 

 the compounds gave 100 percent kill at 5 percent, but only half of them 

 showed much toxicity at 1 percent. The lower monoalkyl formamides up to 

 the butyl group were completely nontoxic to the milkweed bug, but the cor- 

 responding formanilides were toxic at 5 percent concentration. 



The adult pea aphids (table h) were most susceptible to 5 percent 

 concentration of the higher members of the formamide series, such as 

 dioctyl, dipentyl, and octyl, which also showed some toxicity at 1 percent. 

 The pentyl and isopentyl formanilides and the dibenzyl and phenethyl for- 

 mamides were also toxic at £ percent. The lower members of the series 

 seemed to show the least toxicity. About one-fourth of the compounds 

 tested were toxic to the pea aphid at 5 percent. 



Of 15 compounds tested against the adult citrus red mite, about two- 

 thirds were toxic at 1 percent, and about half at 0»5> percent (table 5). 

 One, N-N-dibenzylf ormamide , gave 100 percent kill at 0.1 percent. Prac- 

 tically all the compounds were toxic at $ percent. 



The 17 compounds not tested against the citrus red mite were tested 

 against adults of the two-spotted spider mite (table 6) . About half these 

 compounds showed over 90 percent kill at 5 percent, two compounds at 1 



