Effect of Thiram-Endrin Formulations on The Germination of Jack Pine and White Spruce Seed in The Laboratory

Pelleting of forest tree seed with thiram and endrin powders has been standard procedure since 1956 when the U.S. Fish and Wildlife Service recommended this treatment as a bird and rodent repellent (7). However, literature has been contradictory conderning the phytotoxicity of these substances. For example, Roy (5) reported that germination of Douglas-fit seed was not inhibited by a thiram-endrin coating, and Hodges and Scheer (4) found that repellents have no effect on germination of longleaf, slash, or sand pines. However, Harrington (3) noted a significant reduction of white pine germination following the application of thiram and endrin. In 1963, Derr (2) recommended a treatment employing an aqueous suspension of thiram (Arasan-42S) and powdered endrin. This liquidpowder treatment is reputed to be safer to prepare ,and to afford a more durable coating than the previous powder-powder formulation. As part of the present study, a liquidliquid treatment was developed as a possible further improvement on Derr's treatment. This treatment employed Arasan-42S and a commercially-available endrin product consisting of a 20 percent concentration of endrin dissolved in a solvent of heavy aromatic naptha (Endrin-20EC). This paper reports on the effect. of these formulations and their separate ingredients on the germination of jack pine (Pinus banksiana Lamb.) and white spruce (Picea glauca (Moench) Voss) seed in the laboratory.

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Author(s): Robert C. Dobbs

Publication: Tree Planters' Notes - Volume 22, Number 3 (1971)

Volume: 22

Number: 3