NO. 1382. 



THE A CARINA OR MITES— BANKS. 



105 



unrolled. They form red- blister-like spots nearly one-fourth inch 

 across. These spots become green by June, and then turn brown, 

 and the tissue becomes hard and corky. The opening- is on the 



Fig. 198.— Round-galls of ax eriophyes. 



/: 



Fig. 197.— Section of an eeineum on leaf. 



under side. As mites often start galls 

 close together, the}^ soon coalesce and 

 form large blotches. Professor Slin- 

 gerland has found that the}^ can be 

 practically exterminated by spraying 

 the trees in winter with kerosene 

 emulsion diluted with 

 from five to seven parts 

 of water. This mixture 

 reaches the hibernating mites in the buds, and kills 

 them there. 



Another species of considerable economic impor- 

 tance is Eriophyii'X olelvoruK Ashmead, the rust mite of 

 the orange and the silver mite of the lemon. It occurs 

 in Florida and California, and lives on both leaves 

 and fruit. On the foliage the mite causes the leaves 

 to l)ecome curled and lose their gloss. On the fruit 

 of the orange the mite produces a hardening of the 

 rind, which becomes brownish in color. The infested 

 orange, although injured in appearance, is l)etter able 

 to stand long shipment, and more juicy than the clean 

 fruit. Upon the lemon the mites cause the rind to 

 become whitened or silvered. The fruit is ])etter for 

 shipment, Init the rind is injured for commercial 

 purposes. The circular eggs are deposited on the 

 leaf or fruit, generally in clusters. The}" hatch in 

 five to ten days. It takes a])Out two weeks to reach 

 maturity. Its food is the essential oil. found in the 

 epidermal cells. ]Mr. Hubbard, who studied this mite 

 more carefully than anyone else, estimated that there 

 may l)e 75.000 mites and eggs on a single leaf. The 

 best remed}' is flowers of sulphur; this may be applied dry, or mixed 

 in with a spraj'ing solution, as kerosene emulsion. 



Another injurious species in this country is the plum-twig gall 

 mite, Ei'Jophi/es pJdijeocoptes Nalepa (also known as CecidojJtes jjrunl 

 Amerling). 



Fig. 199.— Erio- 

 phyes VITIS. 



