Abstract of Dissertation Presented to the Graduate Council 

 of the University of Florida in Partial Fulfillment of the Requirements 

 for the Degree of Doctor of Philosophy 



BIOLOGICAL STUDIES ON THE CITRUS TREE SNAIL 

 Drymaeus dormani (BINNEY), AND THE CITRUS RULT MITE 

 Phyllocoptruta o leivora (ASHMEAD) , 

 AS WELL AS THE EFFECT OF DIFFERENT ACARICIDES 

 ON THE CITRUS RUST MITE 



By 



Michael Edward Bledsoe 



December 1977 



Chairman: D. R. Minnick 



Major Department: Entomology and Nematology 



An arboreal snail, Drymeaus dormani (Binney), and several acaricides 

 were evaluated for their effect on the citrus rust mite, Phyl locoptruta 

 oleivora (Ashmead), on citrus in North Central Florida. D^. dormani was 

 found to have the potential to suppress the citrus rust mite populations 

 by ingestion of the mites and their spermatophore as well as by 

 deposition of mucilage on the fruit surface. Studies using scanning 

 electron microscopy to observe the fruit surface, where snails had 

 grazed, demonstrated the removal of all microbiota. D. dormani feces 

 were determined to contain fungi, whitefly pupae, citrus rust mites, 

 citrus rute mite spermatophores , and other mites. 



Snail grazing and motion were demonstrated to be dependent on 100% 

 relative humidity. D_. dormani potential for removal of fungi and citrus 

 rust mites was determined. 



Studies of citrus rust mite intrinsic and extrinsic orientation on 

 Valencia orange failed to demonstrate tree orientation, while orientation 

 on the fruit was greatest at the marginal (semi-shaded) areas. 



VI 



