SYSTEMIC INSECTICIDE CONTROL OF SOME PESTS 

 OF TREES AND SHRUBS-A PRELIMINARY REPORT 



Information supplied by entomologists of the Shell 

 Development Company of Modesto, California, in the 

 spring of 1959, indicated the possibility of controlling 

 the smaller European elm bark beetle, Scolylus multi- 

 striatus (Marsham), on elms by injecting a new chemical, 

 SD-3562, into the trees, fig. 3. The beetle is well 

 known as the principal vector of the Dutch elm disease. 

 Later developments suggested the possibility of con- 

 trolling other pests of trees and shrubs with bark or 

 soil applications of SD-3562, figs. 1 and 2. This chemi- 

 cal, an organic compound, 3-(dimethoxyphosphinyloxy)- 

 N,N-dimethyl-cis-crotonamide, is a systemic insecticide. 

 When taken up by a plant, it is translocated to the 

 stems and leaves, making the plant poisonous to insects 

 that feed on it. 



Technical grade SD-3562, used in the experiments 

 reported in this paper, is a brown liquid with a mild 

 odor. It is water soluble and is highly toxic to warm- 

 blooded animals as well as insects. In the research 

 reported here, the chemical was used undiluted except 

 when placed in the soil around trees or shrubs. 



The insecticidal activity of technical SD-3562 is 

 proportional to the amount of alpha isomer (actual 

 SD-3562) in the solution. Early preparations, with only 

 30 to 50 per cent alpha isomer, were used in our experi- 

 ments of 1959 and I960. Improved manufacturing pro- 

 cesses made possible an increase in the alpha isomer 

 to 75 per cent. The preparation with the higher concen- 

 tration of alpha isomer was used in the experiments 

 we performed in 1961. At the time of publication of 

 this paper, SD-3562 is not available for use by the 

 public. 



PHYTOTOXICITY TESTS 



Before tests were undertaken with insects, 

 phytotoxicity tests with SD-3562 were conducted on 

 American elm trees in a nursery plot at Urbana- 

 Champaign. The trees, about 3 inches in diameter at 

 breast height (dbh), were treated on June 19, 1959, with 

 technical SD-3562 at rates of 0.5, 1, 2, 4, and 8 ml per 

 inch of tree dbh. The undiluted chemical was measured 

 with a syringe and placed in holes three-eighths inch in 

 diameter bored at a downward angle into the trunk of 

 each tree at about 3 feet above the ground, fig. 3- In 



•L. L. English is Entomologist and Walter Hartstim is Assistant 

 Plant Pathologist, Illinois Natural History Survey. Robert Snetsinger, 

 Robert Kukla, and Clifford Scherer assisted with the work reported 

 here. Howard W. Fox, Forester of Sinnissippi Forest, and Noel B. 

 Wysong, Chief Forester, Forest Preserve District of Cook County, 

 co-operated in the field tests. Wilmer Zehi took the photographs. 

 Mrs. Anne R. Dreyfuss and James S. Avars edited the manuscript. 

 This paper is printed by authority of the State of Illinois, Ch. 127, 

 IRS, Par. 58.22. 



L. L. ENGLISH AND WALTER HARTSTIRN* 



the following pages, this method of treating trees will 

 be designated as injection. 



There was no foliar injury to the trees at dosages 

 of 0.5 and 1 ml per inch of tree dbh. At a dosage of 

 2 ml there was slight injury to the foliage, and at 

 dosages of 4 and 8 ml there was severe damage, re- 

 sulting in complete defoliation. 



TESTS WITH BARK BEETLES 

 ON NURSERY TREES 



Early May is believed to be the proper time for 

 treating American elm trees with a systemic insecticide 

 to prevent the first brood of elm bark beetles from 

 infecting the trees with Dutch elm disease. In 1959, the 



Fig. 4. — Cylindrical sleeve cage for confining insects 

 on branch of a honey locust tree. 



