December, 1958 Carter: Applied Botany and Plant Pathology 



159 



ments had not been worked out, the 

 uladiolus industry in Illinois would have 

 succumbed. 



Among other noteworthy accomplish- 

 ments achieved by Natural History Sur- 

 vey pathologists in the field of floricul- 

 tural pathology are the following: control 

 of peony measles with an Elgetol ground 

 spray (Creager 1941r, 1943fl) ; control 

 of black mold of rose grafts by chemical 

 treatments (Creager \94\b) ; control of 

 calla rots by chemical treatments 

 (Creager 1943^)) ; establishment of viruses 

 as the causes of peperomia ringspot 

 (Creager 1941fl), carnation mosaic and 

 streak (Creager 1943f, 1944, Forsberg 

 1947), and coleus mosaic (Creager 

 1945) ; clarification of the Fusarium dis- 

 ease complex in gladiolus (Forsberg 

 1955rt) ; discovery of the vascular phase 

 of the Curvularia disease of gladiolus 

 (Forsberg 1957) ; discovery of scab on 

 violets in Illinois (Forsberg & Boewe 

 1945); control of Thielavia root rot of 

 sweet peas (Creager 1942); control of 

 bacterial scab of gladiolus by use of soil 

 insecticides (Forsberg \955b) . 



The value of an insecticide in the con- 

 trol of bacterial scab of gladiolus became 

 apparent in 1953 when gladiolus corms 

 were treated with a seed protectant which 

 contained an insecticide in addition to a 

 fungicide. This treatment resulted in the 

 production of corms free of bacterial 

 scab and free of injury caused by white 

 grubs. Results of this treatment supported 

 observations that white grubs are instru- 

 mental in spreading bacterial scab. Suc- 

 ceeding tests showed that 25 per cent al- 

 drin granules applied to the soil at the 

 rate of 4 or 8 grams per 10 feet of row 

 prevented white grub injury and bac- 

 terial scab. 



Identification and Extension 



During each growing season the Sec- 

 tion of Applied Botany and Plant Pathol- 

 ogy receives for examination and diagnosis 

 several thousand samples of trees, shrubs, 

 and other plants suspected by Illinois 

 residents of being diseased. Diagnosis 

 results and treatment recommendations 

 are sent as soon as possible to the persons 

 sending the samples. 



Most of the samples received are from 

 elms suspected of being affected with 



Dutch elm disease. To handle the labora- 

 tory diagnoses requires the full-time help 

 during the summer months of four ad- 

 ditional persons: one mycologist, two lab- 

 oratory technicians, and one stenographer. 

 It is anticipated that the demand oc- 

 casioned by Dutch elm disease for service 

 from Natural History Survey personnel 

 will continue indefinitely. 



To supply the demand from hundreds 

 of communities and individuals through- 

 out the state for information on identifi- 

 cation, control, and other aspects of 

 Dutch elm disease has occupied a major 

 portion of the time of one plant pathol- 

 ogist. Educational material on Dutch elm 

 disease has been prepared for distribution ; 

 this has included mimeographed leaflets on 

 control and other phases of the disease, a 

 series of news releases, kodachrome trans- 

 parencies, black and white photographs, 

 specimens, exhibits, maps, tables, and 

 graphs. Technical advice and information 

 were furnished the Illinois State Cham- 

 ber of Commerce for two state-wide con- 

 ferences on Dutch elm disease, one in 

 1955 and one in 1956. These conferences 

 provided specific and detailed information 

 on the nature and control of the disease. 

 Outstanding authorities on Dutch elm 

 disease in the United States were on the 

 programs. Additional activities have in- 

 cluded aid in field identification of the 

 disease, aid in local surveys, training and 

 instruction in collecting specimens, set- 

 ting up laboratories for final diagnosis 

 of the disease, and making laboratory 

 diagnosis of each of several thousand 

 specimens received each j^ear. 



Each year, activities of an educational 

 or extension nature by staff members of 

 the Section of Applied Botany and Plant 

 Pathology include talks on plants and 

 vegetation of Illinois, and on diseases of 

 trees, shrubs, and floricultural crops. Ex- 

 aminations are made of numerous plant- 

 ings of ornamental and economic crops 

 in various parts of the state. Numerous 

 pasture lands are examined in co-opera- 

 tion with members of the University of 

 Illinois College of V^eterinary Medicine 

 for plants poisonous to livestock. Many 

 plants examined in the field or received 

 through the mail are identified for farm- 

 ers, homeowners, and other interested 

 persons. 



