INJURIOUS TO CARROT AND RELATED CROPS 195 



Fig. 123. — Adclphocoris 

 rapidus, adult ( X 5|). 



are blanching, puncture the tender stalks, producing large 

 brown wilted spots and a blackening of the tissue at the joint. 

 This trouble is known among celery-growers as black joint. 

 The injury mars the appearance of 

 the plants, lessens their market value 

 and causes considerable loss. Cab- 

 bage, cauliflower, turnip, salsify and 

 cucumber are also subject to attack, 

 but serious injury to these plants is of 

 rare occurrence. 



It is rarely possible to prevent attack 

 by the tarnished plant-bug because the 

 injury is inflicted by the adults that 

 have developed on wild plants, 

 common weeds that are everywhere 

 present. They are too active to be hit by a spray and so 

 resistant to insecticides that it is impossible to kill them with- 

 out using some material that would injure the plants. Clean 

 farming is often recommended as a means of reducing the 

 numbers of the bugs, but under 

 ordinary circumstances gives little 

 if any relief. 



Another plant-bug, 

 AdelpJwcoris rapidus 

 Say, is often associated 

 with the tarnished 

 plant-bug, feeding on 

 potato, sugar-beets, cel- 

 ery and cotton. It 



also feeds on numerous Fig. 125. — Adelphocons rapi- 



weeds and is sometimes ^"'' ^^^^ '^^^^ ''^""^^ ^ >< '^^• 

 injurious to the fruit of the strawberry. The adult (Fig. 123) 

 is a little over i inch in length. The head, legs and prothorax 

 are yellow ; there are two black spots near the hind margin of 



Fig. 124.— Egg 

 of Adclphocoris 

 rapidus ( X 23) . 



