- 18 - 



VJash. The Nature of Resistance to Fluoride Fumigation Found 



Amonp: Ponderosa Fine. Prunes, Apricots and Gladiolus , (1) 

 Correlate stomatal numbers, size, and position with reaction of 

 Pinus ponderosa , Prunus armeniaca . Prunus domestica and Gladiolus 

 plants to fluoride fumigation; (2; correlate cutical thickness, 

 epidermal thickness and other morphological features of given 

 plants with reaction of those plants by hydrogen fluoride; (3) 

 learn influence of 30 species of Prunus rootstock on response of 

 4 corrjnercial prune varieties and A commercial apricot varieties 

 to fluoride fumigation. 



PI. Path. 1322 (W-39-See ARS-23-8-18) 



Wis, Diseases of Ornamental Plants , Increase quality and 



marketability of greenhouse and of nursery ornamental plants 

 by prevention or control of plant diseases. Learn any necessary 

 modifications for State grov/ing conditions in described control 

 of diseases on ornamental plants. Plans will vary with individual 

 problems, but procedure in most such cases involves: Examination 

 of affected plants; tests to learn presence and identity of any 

 bacterial, fungal, or viral agents; inoculations to healthy 

 plants to test pathogenicity; developnent of suitable control 

 measures • 



PI. Path. 981 



Insect Control 



Ariz, Insect Parasites and Predators of Insect Pests of Arizona 



CropsT To (1) learn: identity, distribution, and relative 

 abundance of insects belonging to families generally recognized 

 as containing species parasitic or predatory on other insects; 

 and where needed descriptive, biological, and ecological infor- 

 mation is lacking; and suggest where future work might be profitably 

 done; (2) evaluate effectiveness of the more common species of 

 insect parasites and predators as control agents. Make related 

 biological and ecological observations for more detailed work. 

 Ent. hOU 



Calif. B iological Control of Red, Yellow. Purple and Other 



Diaspine Scales on Citrus, Avocado, Walnut and Ornamentals . 

 To (1) search for, introduce, rear in quarantine and study 

 biological and natural enemies new to California; (2) colonize, 

 recover, and evaluate effectiveness of introduced natural enemies; 

 (3) evaluate effectiveness of already established natural enemies 

 and develop methods to increase efficiency, if needed; and iU) 

 evaluate effect of sprays, dusts, and fumigants on natural enemy- 

 host population interactions in field and develop methods to 

 reduce to a minimum the adversity of such materials. 

 Biol. Control 1/+93 



