OBSCURE SCALE ON THE PECAN AND ITS CONTROL 



Attack by this insect results in the gradual killing of branches. 

 Those most commonly killed range in size from the smallest up to 

 those approximately 3 inches in diameter. Branches thicker than 

 3 inches are seldom killed, though they may be weakened to such an 

 extent that they will not produce normally if at all. The slow 

 progressive killing of infested branches gradually reduces the number 

 of fruiting limbs, besides weakening the whole tree and rendering it 

 more subject to attack by borers or other insects, and diseases. 

 Trees lacking proper fertilization, cultivation, and care are the most 

 often seriously infested, but many trees in well-cared-for orchards 

 have also been found seriously infested. 



GENERAL DESCRIPTION OF THE STAGES 



The entire life of this scale insect, except the brief presettling, or 

 crawler, stage and the short active life of the adult male, is spent 





Figure 2.— Appearance of an infestation of the obscure scale on pecan: A, A partly encrusted infestation; 

 B, a completely encrusted infestation. X 8. 



beneath the protection of a waxy scale covering. At all other times 

 the insect is concealed and cannot be seen without first removing the 

 scale covering. 



The eggs are ellipsoidal, about 0.25 mm long, light purple to laven- 

 der, and frequently have a whitish bloom. 



The young, or crawlers, appear as tiny indistinct specks moving 

 over the surface of the bark. They are oval and pale salmon-pink, 

 save for the tiny orange-colored rear end, or pygidium. The pygidium 

 retains its orange color through all of the stages in which it is present. 

 After finding a place to settle, the young insects begin to secrete scales 

 which are at first white and circular, but soon become slightly longer 

 than broad, and gradually take on the coloration of the surface on 

 which they rest (fig. 3). The first-stage larvae beneath the covers 

 soon become silvery with a pink tinge, but are otherwise like the 

 crawlers save for their gradually increasing size. 



