/v 1 May 1949 1-777 United States Department of Agriculture Agricultural Research Administration Bureau of Entomology and Plant Quarantine PRELIMINARY TESTS ON N-SUBSTITUTED PHTHALIMIDES AS INSECTICIDES By G. T. Bottger, Division of Control Investigations, and S. I. (rertler, Division of Insecticide Investigations Twenty-five N-substituted phthalimides have been tested in the laboratory of this Bureau at Sanford, Fla. , or at Anaheim, Calif. They may be represented by the general formula Si c \ N-R where R represents an aliphatic, aromatic, or cycloaliphatic radical. All the compounds were prepared in a similar manner by heating phthalic anhydride with an amine at a temperature high enough to split off water and form an N-substituted phthalimide. All compounds were tested as dusts, either undiluted or at 5C w pe rcen ^ concentration in pyrophyllite. Two of the most toxic materials were also tested as 10-percent dusts against insects, and as 1-percent sprays to determine their phytotox- icity. Seventeen of these compounds are included in a previous report (E-729) on tests with miscellaneous synthetic organic compounds. For comparative purposes, tests were made with the standard in- secticides DDT, derris, gamma benzene hexachloride, lead arsenate, and pyrethrum which contained 0.60 percent of pyrethrin I and O.63 percent of pyrethrin II. The following insects were used in the tests; Armyworm (Cirphis unipuncta (Hftw. )) Celery leaf tier ( Phi yc taenia rubigalis (Guen. )) Cross-striped cabbageworm ( EvergeBtis rimosalis (Guen*)) Diamondback moth ( Plutella maculipennis (Curt.)) Large milkweed bug ( Oncopeltus fasciatus (Dall. )) Melonworm (Diaphania hyalinata (L. )) Southern armyworm ( Prodenia eridania (Cram.)) Southern beet webworm ( Pachyzancla bipunctalis (F«)) Squash bug ( Anas tristis (Peg.)) Striped blister beetle ( Epicauta vittata (F. )) Sweetpotato weevil ( Cylas formicarius elegantulus (Sum.)) - 2 - All insects were reared in the laboratory exoept the striped blister beetle and the squash bugs, which were collected from field populations* In tests with lepidopterous larvae, sections of leaves were dusted in a settling chamber and then placed in petri dishes with the test insects* Large milkweed bug nymphs, squash bugs, and adult sweetpotato weevils were placed in crystallizing or petri dishes, where they were dusted by placing the dishes in the bottom of a settling oham- ber* After the insects were dusted, they were confined with untreated food during the test period* Twenty-four to thirty insects were used in each test* The results of tests with the standard insecticides are presented in%ble 1. Data on eight compounds tested as undiluted dusts are presented in table 2* Sixty-seven percent mortality of the oross-striped oabbageworm occurred among insects fed foliage dusted with a light deposit of N-ethyl- phthalimide* This oompound also showed some toxioity to the melonworm and the sweetpotato weevil, but none to the southern armyworm* N-Iso- butylphthalimide and N-propylphthalimide were also toxic to the cross- striped cabbageworm and the melonworm* However, N-isopropylphthalimide appeared to be the most effective against a greater number of inseots* In table 3 are presented the results of tests made with 17 compounds tested as 50-percent dusts against the melonworm, the southern armyworm, and the southern beet webworm* None of these compounds were effective against the melonworm or the southern armyworm* However, all exoept N-(£-tolyl)phthalimide showed some toxicity to the southern "beet webworm* When tested for phytotoxicity as 1-percent sprays, N-propylphthali- mide caused slight to moderate injury to beans, collards, potatoes, Swiss chard, and squash, but N-isopropylphthalimide caused no injury to green foliage of bean, collards, cotton, okra, peas, pumpkin, and Swiss chard* These two compounds, when tested as 10-peroent dusts, were not effective against the armyworm, the celery leaf tier, or the milkweed bug, but "were toxic against the diamondback moth* N-Isopropylphthalimide was consider* ably the more toxic of the two compounds against this insect* •H M © bO oJ U © 4 CO 34 O a, © aJ !-. a> t» < © U s* © CJ +> &| TO -H © © o< o HP •H © © o txO a) •H 1-* O Pn © bD aS •P W ■P o © a M o u o ■H a 1 © o In © a, c O Oi o 5 © bO OlOO O CO o iH r-t I I I I I C-- O <* oomoioo ,h ^ co •* c- WWHNNH 13 • • u © faD O O 4) fl -rl "d Xl 13 OH O S5 CO S © © -d © i iH •H 3 o -p 4 -p ■P © «H TJ © iH Oi © X> O -p © Si o © p as a o © UO bO-p O 1 «H 3 ct) Si CO Oh CO O m ^- +> 45 tj • • S.TJ o J5 n «*{ fo h • 3 - i-i CM CO C* I I 8 •H CO CO •a Si aj r-t rH O o © a o O -d © © m © I 5j bO © •a © faO 10 o OlOrirt • • 1 © •P O U CM 4?« I 0» 8 O Ud O O to IQ CVJ CM CM CM © ■8 Si © O a s bO •H iH CO »d Si at co •H a O CO E-t Q Q 8 • •0 •H Sh O r-i U3 X Jh CM a> • • K 5 •p as © CO 43 -H © CO © aS Si fl i a © g W S -0 (3 bo oS © © CQ h5 s 8 » 10 8 Cft CM S £ •P • s "8 ■P © © u 9 •a n •H bO rH ^ X © tn cu OS -H 3 »i 0«.p CO CO <0 vO • • OO w •P -P © © CO •p o © CI •H co co 23 - to I O lO CO I 1 © to CO to c~ O OD Q (i iH iH CO CO CM tO OJ ,H o o o o o o IIOI IIOO I I I I I I I I I o p o £> C- O o o o CO CO CO CO CM CM o o o o t> t> t>- iH iH rH r-i CM LO LO tO O CO CO CO CM CM CM CM tO lOOlOlOLDlOOO 1 ^ IOHlA©tO©OCO© tOtOcOCMtOCMCMCMCM 1* O O P tJ X) • • • o o O ■o x) *d © ■8 u © • a ,3 w 2 '* a co Xt fl o S o o ft o © •p at 4> U si © • ,cj t»0 X> O O «H a aw •3 fl x» o U -H U at 44 at co H ftiH to CJ> ft O CO •sal s -bis o^& O CO ft CO 6 1 p co g p S 1 CO M to o o iH -B u © o o a CO £ •P © B J 1 o sp3 ^° r^ ft W -p Cj © || co co ra * & e © © XJ .£ ft ft o O I o o CM © iH ■s EH © © bD.p s5 y to CO CM 9 © © fa © o fa •p o © m a 9 •H •p fa ■p d © s © fa p g I I I o o o taO| O o $ O Q O CM CM CM tO tO K. 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