390 STATE HORTICULTURAL. SOCIETY. 



ent injury. As a repellant it did some good, though not equal to carbolic 

 acid. Other repellants, such as coal-tar water, salt, sulphur, etc., were 

 tried but were of no evident effect. 



The only remedy found which would kill the bugs was hot water. Celery 

 will endure a stream of water heated to 175" Fahrenheit, and the bugs 

 succumb at 155°. 



MEANS OF CONTEOL. 



We now come to the most important part, viz.: how to protect from 

 future attacks. With the present knowledge that we have, probably the 

 best method will be a combination of the carbolic acid and hot water. It 

 is probable that the bugs will appear about the same time again next 

 season, and careful watch should be kept from the 10th of July on. When 

 they appear it will be in large numbers in some spot along the margin, and 

 this is the time to treat them before they spread over the field. Carbolic 

 acid can then be used on the plants surrounding the bug-infested patch for 

 some distance back, or to make it more certain, on the remainder of the field; 

 then, while the bugs are held in this little patch, dose them with hot water. 

 It should be between 155 and ]75 degrees Fah. when it strikes the bugs. 

 The use of hot water is impracticable in a large field, but if used only on a 

 .little patch, is not so difticult. It may be applied with a cup from a pail 

 or with a spray pump without the spraying nozzle. The water must be 

 thrown in a stream, as it will cool too rapidly when thrown in a spray. The 

 application of hot water will necessitate the use of a thermometer that the 

 temperature may be accurately known. 



A good precaution against attack would be to keep all weeds in the 

 vicinity of the celery fields and along ditches cut down close through June 

 and July so as to prevent the bugs from breeding on them. Unlike the 

 tarnished plant bug, the amount of rubbish under which the negro bug 

 can hibernate does not seem to affect its numbers in the least. 



THE 13-SPOTTED LADl BIRD BEETLE (Hippodamia 13-imnctata, Linn.). 



Many suspected this spotted beetle, which was so often 

 present with the little negro bugs or found at the node 

 after it was left by the bugs, of helping harm the celery; 

 but the beetle was there only for the sap that issued from 

 the wounds made by the bug. The beetle is one of our 

 Fig. 9.— The three stages little friends as it feeds on plant lice and seldom, if at all, 

 bfrdte't^irna^Siif ' on the plants themselves. 



