INSECTS INJURIOUS TO CITRUS GROVES. 521 



show as minute black spots and the cast skins, where ag- 

 gregated together, constitute whitish silvery patches. 

 After a few weeks the leaves curl, shrivel and fall, more 

 than one-half of the leaves often coming down and from 

 one-third to two-thirds of the immature fruit. In 1899 

 one grove located in Citra, Fla., reported a crop of only 

 about ten thousand boxes from the heaviest bloom the 

 grove had ever put forth, whereas it had yielded twenty- 

 four thousand boxes the preceding year, the whole shrink- 

 age of product being attributed to the six-spotted mite. 



The rainy season of June and July causes the mites 

 to practically disappear and they remain in such small 

 numbers during the latter part of the year that they are 

 rarely noticed at all. Vigorous trees, especially those 

 grown on high hammock land or low, moist soil, are not 

 apt to be injured, and where irrigation or artificial wat- 

 ering is practiced damage is slight. Drenching the trees 

 with water from a hose, where the water supply is abun- 

 dant, as in the case of irrigated groves, meets every de- 

 mand. 



Treatment: Formulas (14), (11), (12) or (13). 



Purple Mite or Red Spider. (Tetranychus mytilas- 

 pidis). The Red Spider appears to be identical with the 

 insect known throughout Florida as the Purple Mite. 

 This insect is quite small, yet distinctly visible to the 

 naked eye. During the summer months they frequently 

 appear in large numbers and cause great damage by caus- 

 ing the fruit to drop and injuring the leaves so that they 

 do not properly perform their functions. The leaves 

 become spotted and lose their natural glossy green color. 



The females are considerably larger than the males. 

 Both are covered with a number of stiff hairs, which act 

 as a protection. The color of these insects is somewhat 



