damage the tips of the plants. The red cedars, about 

 3/^ feet high, were heavily infested with the pest. One 

 plant was used for each of the following dosages of 

 improved technical SD-3562: 2Y 2 , 5, 10, and 20 ml, 

 each diluted with water to make 1 gallon. On July 11, 

 1961, the diluted chemical was injected into the soil 

 in the same manner as in the experiment described for 

 control of bagworm on arborvitae. One untreated plant 

 was used as a control. 



Within 15 days after treatment, very substantial 

 kills of larvae and pupae were obtained, even at the 

 lowest dosage of 2% ml per plant. Twenty-two days 

 after treatment, the kill was 100 per cent at dosages 

 of 5, 10, and 20 ml per plant. All dosages provided 

 practical control for the season, table 8. The chemical 

 produced no apparent injury to the red cedars. 



Mimosa Webworm on Honey Locust. — On July 24, 

 1961, a honey locust tree with a trunk 4 inches dbh 

 was treated with 80 ml of technical SD-3562 in 8 

 gallons of water. One quart of the dilute chemical was 

 injected into the soil in each of 32 places in a regular 

 pattern around the tree beginning 1 foot from the trunk 

 and extending approximately to the periphery of the 

 branch spread. This treatment failed to control the 

 larvae of the mimosa webworm. 



Three additional trees ranging in size from 3/4 to 

 4 l A inches dbh were treated on July 26, at rates of 5, 

 10, and 20 ml per inch with technical SD-3562 in the 



same manner as above. When control of the mimosa 

 webworm was not evident within 3 weeks, the treatment 

 was repeated, but with each dosage in 4 gallons of 

 water injected into eight places in the soil 1 foot from 

 the trunk of the tree. These two soil treatments on 

 each of the three trees failed to control larvae of the 

 mimosa webworm. 



DAMAGE TO BARK AND TISSUE 



The application of technical SD-3562 to small 

 honey locust trees by injection killed a considerable 

 area of the bark and tissue around each injection hole, 

 fig. 8. Serious injury was caused when the chemical 

 was applied over striated bark, fig. 9. The bark of a 

 pin oak stippled with an ice pick before being treated 

 with SD-3562 was noticeably injured within 17 days 

 after treatment, and by May, 1962, the injured areas 

 had greatly enlarged. 



On honey locust trees, the uninjured trunk areas 

 treated with SD-3562 in 1961 became delineated with 

 a slightly darker color of the bark, but no evidence of 

 actual bark injury was observed until the following 

 spring. When examined in May, 1962, some trees 

 showed no signs of bark injury. Others showed various 

 degrees of injury in the form of cracks or checks in 

 in the bark, fig. 10. Injury appeared to be confined to 

 the outer phloem (bark). Additional research will be 



Table 7. — Per cent of bagworms found dead on each of several days on each of six arborvitae shrubs, about 4 feet 

 high, five of which had been given soil treatments with improved SD-3562, July 11, 1961. Each lot of bagworms was 

 placed on a shrub, left there for 7 or 8 days, and removed, examined, and counted on the day indicated. 



Dosage Rate, 

 Ml Per Plant 



7th 



15th 



Per Cent of Bagworms Dead 

 on Indicated Day After Plant Treatment 



22nd 



29th 



36th 



■43rd 





 5 

 10 

 20 

 40 

 80 



41.0 



87.0 



91.5 



100.0 



100.0 



Approximate length 

 of bagworms, 

 inches 



3/8 





 47.6 

 100.0 

 100.0 

 100.0 

 100.0 



1/2 



19.2 

 59.4 

 100.0 

 100.0 

 100.0 

 100.0 



1/2-3/4 



3.2 



20.0 

 96.5 



100.0 

 100.0 

 100.0 



s 8-3 A 



24.1 

 22.2 

 91.5 

 92.9 

 91.3 

 100.0 



3 ■) 



8.7 

 15.0 

 50.0 

 77.7 

 95.1 

 100.0 



3 4-1 



Table 8. — Per cent of midge population (Oligotrophus sp.) found dead on each of several days on each of five 

 Canaert red cedar plants, four of which had been given soil treatments with improved SD-3562, July 11, 1961. The per 

 cent of the midge population dead was determined by counts made on 100 red cedar buds each day indicated. 



Dosage Rate, 

 Ml Per Plant 



7th 



l<uh 



Per Cent of Midge Population Dead 

 on Indicated Day After Plant Treatment 



22nd 



: - th 



36th 



40th 



Mth 



-0th 







2Vi 



5 

 10 

 20 



20.8 

 18.3 

 23.1 

 20.7 

 26.7 



8.1 



80.0 



95.6 



100.0 



96.3 



23.5 



82.7 



100.0 



100.0 



100.0 







91.5 



100.0 



100.0 



100.0 



2.3 



100.0 



4.0 



10 



