6 MISC. PUBLICATION 49 8, U. S. DEPT. OF AGRICULTURE 



oranges are likely to be larger than on other varieties. They coalesce 

 into large areas, sometimes an inch in diameter. Early and mid- 

 season oranges are more susceptible to pitting than are the late- 

 ripening varieties, the Pineapple variety being the most susceptible. 

 Smooth-skinned fruit is more likely to develop pitting than is coarse 

 fruit, and those of small sizes are more susceptible than large ones. 



IN THE FIELD 



Pitting, as seen in the field and packing houses, differs considerably 

 from that which develops in storage or on the market. Under field 

 conditions pits on grapefruit are rarely as much as an inch in di- 

 ameter and rarely coalesce, and the affected areas remain firm. Pits 

 rarely lead to invasion by PenicUUum or the stem-end rot fungi 

 before harvest. 



ON THE MARKET OR IN STORAGE 



Pits found on fruit on the market or in storage are usually one- 

 fourth to one-half inch in diameter (pi. 4, A) where they occur 

 singly, but they may enlarge to V/ 2 to 2 inches or more where several 

 pits coalesce. They are usually larger on grapefruit than on oranges, 

 although on grapefruit held at 32° F. they are typically less than 

 one-fourth inch in diameter (pi. 4, B). Softening often occurs 

 underneath the pits and may lead to invasion by blue mold, the 

 withertip fungus, or the stem-end rot fungi. The pulp beneath large 

 pitted areas usually has a tainted taste. In affected areas of the rind 

 the oil glands are particularly noticeable in early stages of the dis- 

 ease, especially on oranges, because in such places they are raised 

 and slightly darker than the tissues surrounding them. In old pits 

 these glands are definitely sunken. 



As noted above, the disease may occur on fruit at time of packing, 

 or it may develop in transit, particularly on Pineapple oranges and 

 on small-sized fruit of Parson Brown, Hamlin, and other midseason 

 varieties. Generally it does not develop until after a storage period 

 of 4 to 6 weeks when it is often accompanied by aging or shriveling 

 of the rind around the stem. It usually is worse at 36° to 40° F. than 

 at either higher or lower temperatures. 



(See 23, 24, Jfi, 52, 57. 58, 59, 61, 62, 89, 90, 91, 109, 110, 111, 112, 

 119.) 



PURPLE SCALE 



(Lepidnxaphes beckii (Newm.)) 



The purple scale is essentially a citrus fruit pest, although its attack 

 is not restricted to plants of that family. The adult female averages 

 one-tenth inch in length. The scale covering, in general color, is a 

 brownish purple, and its shape resembles that of an oyster shell 

 (pi. 3, 67). < . 



Injury to the fruit is due directly to the feeding of the insect, which, 

 if it occurs on ripe fruit, has a tendency to delay coloring. The scales 

 are so firmly attached to the fruit that they are removed with great 

 difficulty by the washing machinery and as a result are very often seen 

 on fruit on the market. 



(See 93, 94, 100, 131, 132, 146.) 



