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2751790 
Technical Report 
Systemic Insecticides in Trees 
Norris, DM 
1967 
HAPAB/67/00299 
Rev 
127-148 
HAPAB The current knowledge of systemic pesticidal action in trees is reviewed, with an emphasis upon use in relatively high-value trees and especially ornamentals. A representative listing of the insects or mites which can be controlled systemically in trees is tabulated along with the insecticide used and mode of treatment. Persistence of systemics and their metabolism in plants are related; persistence is defined as the time interval between the initiation and the cessation of pesticidal action in a tree that has been systemically treated. Persistence of insecticidal action can be influenced by extended uptake, by the dosage given, and by the metabolism and degradation of the insecticides by the plant. Residual activity can vary from 2 days ( Phosdrin ) to several years ( R-6199 in pine trees ); this extremely short residual activity of Phosdrin is attributed to its extreme volatility and hydrolytic instability. The persistent insecticide phorate exidizes in the plant at a rate of about one-half that observed with a less persistent compound ( Di-Syston ). Activity in Isolan- treated foliage decreases steadily after the period of initial uptake. The parent compound for R-6199 does not oxidize in lemon after 30 days. Chemically, the tertiary amine structure of the free thiol-isomer base is involved in the persistence of this systemic through the formation of tertiary ammonium salts with strong acids such as oxalic, picric, and phthalic. Furthermore, the n-alkyl quaternart ammonium compounds are very promising systemic fungicides against vascular wilts of trees, and evidence indicates that such compounds with alkyl group of less than 12 carbons may possess adequate mobility and fungitoxicity in the plant. Dimethoate undergoes oxidation and hydrolysis in plants and phosphorothioate is apparently responsible for most of the systemic insecticidal activity of the compound. The metabolites of phosphamidon and Bidrin have been studied in cotton leaves. ( 90 references ) RESIDUES AND THEIR MONITORING 67/03/00, 12 1967