48 MISC. PUBLICATION" 168^ U.S. DEPT. OF AGEICULTUEE 



entirely satisfactory method of controlling the tarnished plant bug 

 is known. Except for a brief period in the spring, these bugs live 

 on various herbaceous plants. Clean culture is helpful by eliminat- 

 ing the favored plants on which the bugs breed, but this cannot be 

 recommended where cover crops are considered essential to the 

 orchard-management program. 



In the northeastern part of the United States, the apple red bugs 

 {Heterocordylus inalinus Kent, and Lygidea mendax Rent.) are re- 

 sponsible for a great deal of injury of the stigmonose type. These 

 bugs cause less distortion of the fruit than the tarnished plant bug. 

 The newly hatched red bugs appear on the shoots of the apple trees 

 at about the blooming period, and may be controlled by the applica- 

 tion of nicotine sulphate in either the pink or the calyx spray, 

 depending on the time when the insects first appear. 



The boxelder bug {Leptocoris tmvittatus Say) also occasionally 

 causes stigmonose. These bugs, which are larger than the tarnished 

 plant bug and marked with red, feed in clusters on maturing fruit. 

 They breed chiefly on boxelder, and when full grown migrate to 

 nearby apple trees. The replacement of boxelder trees in the 

 vicinity of orchards with other kinds of shade trees will prevent 

 injury from this cause. 



The rosy apple aphid {Anura'phis roseus Baker) also causes a form 

 of stigmonose. These insects feed on the newly formed small apples, 

 and cause them to be very much stunted, knotty, and distorted, 

 usually with a characteristic puckering of the surface around the 

 calyx end (pi. 19, E). The rosy aphid may be controlled by the 

 application of a " delayed dormant " spray at the time when the 

 bud tips show green. The most effective spray consists of three 

 eighths to one half pint of nicotine sulphate (40 percent nicotine) 

 to 50 gallons of water. The nicotine sulphate solution may be added 

 to the concentrated lime-sulphur spray used at this time for the con- 

 trol of San Jose scale. The oil sprays, which have to a considerable 

 extent replaced lime-sulphur for dormant spraying, are less depend- 

 able for aphid control, although with the addition of nicotine they 

 are effective when applied in the delayed dormant period. Certain 

 eastern experiment stations are also recommending the use of oil 

 spraj^s with the addition of 0.5 percent of cresylic acid, at any time 

 during the dormant period. 



The apple maggot or railroad worm may cause small dimplelike 

 spots in the surface of the apple as already described, but when the 

 fruit is cut open, small winding tunnels are usually found, extending 

 deep into the flesh (p. 5). 



SUNBURN AND SUN SCALD 



Apples sometimes exhibit a golden or brown color or a bleached 

 appearance on the side that has been most exposed to the sun. 

 On light-skinned varieties the injury may have much the appear- 

 ance of an early stage of scald, but the tissue is firm and shows 

 no sign of breakdown. On red-skinned varieties the exposed area 

 is likely to show a browning or bronzing rather, than an attractive 

 red. 



