Webworm infestations on three other honey locust 

 trees were quickly brought under control with appli- 

 cations of technical SD-3562 to uninjured bark at the 

 rate of 3 ml per inch of trunk dbh. 



Results of the tests with these four trees were 

 evaluated at weekly intervals by examining the larvae 

 in nests clipped from the treated trees and from near- 

 by untreated trees. No sign of phytotoxicity was 

 observed during 1961 in any of the treated trees. 



TESTS WITH FALL WEBWORM ON OAKS 



Five small oak trees, red, pin, and bur, 1 to 2/^ 

 inches dbh, were treated on July 31, 1961, with im- 

 proved technical SD-3562 injected into the soil, fig. 2, 

 at dosages ranging from 5 to 40 ml per inch of trunk 

 dbh. Each dosage was diluted with 8 gallons of water. 

 One tree was left untreated as a control. At weekly 

 intervals, beginning 2 weeks after treatment and ending 

 with the fifth week, larvae of the fall webworm were 

 confined in cages, one cage on a limb of each of the 



Fig. 7. — Trunk of a pin oak tree 17 days after the bark 

 j had been stippled with an ice pick and SD-3562 had been 

 applied to the surface. Circular areas are depressed as a 

 i result of tissue damage caused by the chemical. 



six trees. Larvae were exposed for 1 week. The results 



were inconclusive. 



Applications of technical SD-3562 to the unin- 

 jured bark of red oak trees, \Vi to 3 inches dbh, at 

 dosages of 1 to 4 ml per inch of trunk dbh also gave 

 inconclusive results. 



In a series of tests on pin oaks, 2 to 3 inches 

 dbh, a dosage of 3 ml per inch of trunk dbh was applied 

 on August 29 by three methods: on uninjured bark, on 

 bark stippled with an ice pick, and into holes drilled 

 in the trunk, one tree for each method and one as a 

 control. One lot of fall webworms was caged on each 

 tree 2 weeks after treatment and another 3 weeks after 

 treatment. Application of SD-3562 to uninjured bark 

 was not appreciably effective against the fall webworm 

 larvae. The chemical apparently did not penetrate 

 uninjured oak bark as readily as uninjured honey locust 

 bark. However, applications of the chemical by the two 

 other methods were highly effective against the larvae. 

 SD-3562 when applied to stippled bark appeared to 

 be taken up by the tree as quickly as when applied in 

 drilled holes. Chemical injury to bark but not to foliage 

 was observed on the treated oak that had been stippled 

 with an ice pick, fig. 7, as well as on the tree drilled 

 with holes. No chemical injury to either bark or foliage 

 was seen in 1961 or 1962 on the tree treated on un- 

 injured bark. 



TESTS WITH SD-3562 INJECTED INTO SOIL 



In 1961, diluted SD-3562 injected into soil was 

 tested against certain pests of arborvitae, Canaert 

 red cedar or juniper, and honey locust. 



Bagworm on Arborvitae. — Six arborvitae plants 

 about 4 feet high were treated July 11, 1961, with im- 

 proved technical SD-3562 at dosages of 0, 5, 10,20, 

 40, and 80 ml per plant, respectively. Each dosage, 

 diluted with water to make 1 gallon, was injected with 

 a pump and wand, fig. 2, into the soil in eight places 

 around the plant and at a distance of about 10 inches 

 from the stem. The wand was slanted under the plant 

 at an angle of about 45 degrees; the holes made were 



6 to 10 inches deep. At the time of treatment, the soil 

 was wet. At about weekly intervals, 30 to 50 bagworms 

 were placed on each plant by hand and left there for 



7 or 8 days before being removed and examined. 



Effectiveness of the chemical was evident within 

 7 days after treatment at all dosage levels; within this 

 period, complete kills were obtained at dosages of 40 

 and 80 ml per plant, table 7. Complete kills were ob- 

 tained 15 days after treatment with dosages of 10, 20, 

 40, and 80 ml; the kill was only partial with the 5-ml 

 dosage. Forty-three days after treatment, the 80- ml 

 dosage gave a 100 per cent kill of bagworms with bags 

 up to 1 inch long. The treatments resulted in no ap- 

 parent phytotoxic injury to arborvitae. 



Midge on Canaert Red Cedar. — Canaert red cedar 

 plants in a local nursery provided an opportunity for 

 tests against a midge, Oligotrophus sp., whose larvae 



