

ANNUAL REPORT, 1934 39 



applied the oil sprays, and it is worthy of note that no direct injury resulted nor 

 was there any apparent increase in the winter injury due to the use of the oils. 

 This was true of both the commercial petroleum oil sprays and the recently de- 

 veloped tar distillate washes. 



In the tests at the college the number of overwintering red mite eggs was 

 moderately large, and there was no significant winter mortality. Consequently 

 the infestation that developed proved serious when unchecked. 



The standard brands of commercial oil sprays, Kleenup, Sunoco, Peninsula 

 Oil Emulsion, etc., gave their usual high degree of control. In addition a new 

 type of soluble wool oil prepared by the Colonial Oil Company proved very 

 effective in its first season's test, giving 98 to 99 percent control. Trees sprayed 

 with this oil showed 88 percent of the leaf clusters free from young mites, and 

 infested leaf clusters averaged 12 mites per cluster of 6 to 7 leaves as compared 

 with 1,968 per cluster on the unsprayed checks. 



Tar Distillate Washes for Overwintering Eggs of Plant Lice in Orchards. Field 

 tests were made with six different types of tar distillate washes and one cresylic 

 acid oil emulsion. These represent a new development in oil sprays and are 

 designed primarily for use in dormant applications, for the control of overwintering 

 eggs of different species of plant lice. The tar oils alone have not proved very 

 efficient against European red mite so that many of the samples on the market 

 today are a combination of tar oil emulsion and petroleum. The samples tested 

 included the following: 



Tar-Petro-Emulsion, Ansbacher-Siegle Corporation, 



a coal tar creosote-mineral oil combination; 

 Tar-O-Emulsion, Ansbacher-Siegle Corporation, 



a coal tar creosote oil; 

 Cres. -Emulsion, Ansbacher-Siegle Corporation, 



a mineral oil-cresylic acid combination; 

 Kleenup-Tar Oil Emulsion, California Spray Chemical Co., 



a coal tar creosote oil with Kleenup; 

 Tarolene, Central Chemical Company, 



a coal tar creosote-mineral oil combination; 

 Tar Oil Wash, Niagara Sprayer and Chemical Co., Inc., 



a coal tar creosote oil ; 

 Tar E. Mul, Niagara Sprayer and Chemical Co., Inc., 

 a coal tar creosote-mineral oil combination. 

 In spite of the severe winter and the possible ill effects upon the trees, careful 

 observation failed to discover injury following any of the above sprays nor was 

 the seasonal development of sprayed trees retarded. The heavy winter mortality 

 of the overwintering eggs of plant lice on these trees caused such an irregular 

 and insignificant hatch on the unsprayed checks that no accurate results from the 

 use of the oils could be obtained. 



Rotenone and Pyrethrum Sprays for Gladiolus Thrips. In tests against gladiolus 

 thrips Cubor spray gave excellent results. This is a rotenone compound in the 

 form of a dry powder. Care must be taken to thoroughly dissolve the powder in 

 water. Considerable agitation was necessary to do this; otherwise the material 

 showed a tendency to collect into drops on drying, leaving large areas of the 

 plant surface uncovered. However, if carefully prepared, this spray appeared to 

 be one of the best of the rotenone group. Ku-ba-tox spray, another rotenone 

 compound, gave fine coverage with no indication of the defects mentioned above. 

 A combination of lead arsenate, molasses, and water caused no injury to plants 



