EXPERIMENT STATION BULLETINS. 389 



and was injured the worst for the first few days, after which the bugs 

 would scatter so that no difference could be noticed. 



The bugs are not general weed feeders like the tarnished plant bug, but 

 are partial to a select few. They were found feeding on five different 

 species bordering the celery fields, viz: * beggar-ticks, stick-tight or fork 

 weed {Bidens frondosa); tick-seed (Coreopsis trichosperma) ; red root 

 (Amarantus retroflexus) ; ground nut (Apios tuherosa) , and great lobelia 

 (Lobelia syphilitica). In addition to these Dr. Riley reports them on 

 rosin weed (Silphiiim) and speed well (Veronica per egrina); Webster, on 

 evening primrose (OEnoihera) ', Forbes, on plantain (Plantago lanceo- 

 lata), and sometimes on rag weed (Ambrosia) and smart weed 

 (Polygonum persicaria). When found on these weeds they are always 

 more plentiful than on celery near by; but in some instances where found 

 in large numbers on these weeds a few days previously, the weeds had been 

 deserted and the celery attacked. All seems to point toward their breed- 

 ing elsewhere than on the celery at present; but even if this is true, 

 should they continue to make celery a food plant, they will undoubtedly 

 make it a breeding plant as well. 



INEFFECTUAL REMEDIES. 



While celery-growers should not be discouraged at the start, for it is 

 probable the bug can be controlled, yet it is quite evident after experi- 

 menting with the remedies usually effectual on such insects, that nearly 

 all the remedies belong to this first class — the ineffectual. Our most 

 effectual remedy on the true bugs is kerosene emulsion and this was the 

 first to be tested on these bugs, but they were too well armored for it to 

 penetrate. They were even placed in the dilute emulsion and forced to 

 swim for five or ten minutes, but they soon recovered when taken out and 

 were as lively as before. The full strength emulsion that would kill the 

 tarnished plant bug as soon as dropped into it, would not kill the little 

 negro bug for several minutes. Similar in nature, but even less effectual 

 was " Little's Chemical Fluid," a prepared sheep dip and insecticide. 



THE MOEE EFFECTUAL EEMEDIES. 



Finding our most effectual remedies that kill by contact were of no 

 avail, we next turned our attention to repellants and here found a vulner- 

 able point. They were driven and scattered by offensive odors. Crude 

 carbolic acid mixed with water at the rate of a tablespoonful to two 

 gallons and sprinkled over the plants or mixed with air-slaked lime or 

 land plaster at the rate of a teacupful to each bushel and dusted over the 

 plants, seemed to serve as a repellant the best of anything tried. The odor 

 from a field sprinkled with carbolic acid water could be detected quite a 

 distance off for at least twenty-four hours after the application was made. 

 The odor from carbolized lime is not nearly so strona: but seems to be more 

 permanent. Lime alone was of little effect. It was intended to procure 

 some gas lime (a refuse product in the manufacture of gas), but none 

 could be obtained, and ammonia water with a strong sulphur and coal tar 

 odor was taken instead. For the plants it had to be reduced at least 

 seven eighths, but the bugs could swim in it full strength without appar- 



* The plants were determined for me by oar station botanist, Mr. C. F. Wheeler. 



