INSECTS INJURIOUS TO CITRUS FRUITS 627 



arusseting of the fruit which reduces its quality mainly by 

 detracting from its appearance but also by reducing the 

 size. Oranges and grapefruit are the greatest sufferers in 

 Florida. Russeted fruits may frequently, even now, be seen on 

 the market. 



Control of the Rust Mite. Weather conditions are a factor in 

 the check of the mites, cold and wet weather being unfavorable 

 to their development. These can not be relied upon to prevent 

 damage and spraying is practiced wherever the mites are 

 abundant. 



Sulphur is the best insecticide for these pests. It may be 

 applied in the form of a dust, mixed with hydrated lime which 

 is used as a carrier, at the rate of one part lime to three parts 

 sulphur. The dusting outfits discussed in the chapter devoted 

 to spraying apparatus are suitable for use in applying this material, 

 but care must be used to see that the dust carries through the 

 dense foliage of the trees. 



Free sulphur mixed with water or with water and soap is 

 a good spray for the mite. Four or five pounds of sulphur, four 

 pounds of soap and fifty gallons water, are about the proper 

 proportions. 



Commercial lime-sulphur testing 32, Baume scale, should be 

 diluted with seventy-five parts of water and will make a very 

 good treatment for the mites. 



Soda-sulphur spray, made as described for the control of the 

 thrips and diluted at the rate of one to forty, is another effective 

 spray. 



Thoroughness is as important as for the treatment of other 

 citrus pests. 



Red Spiders * 



These pests are, like the mites, members of the class Arachnida 

 and the order Acarina, being, in fact, true mites themselves. 

 They are larger than the rust mites and one species is quite red 

 in color, being called the Florida red-spider, while the other is 



* Tetranychus mytilaspidis Riley (or T. citri McGregor. ) and T. sex- 

 maculatus Riley. See H. J. Quayle (1. c.). 



