MECHANISMS FOR MOVEMENT OF FUNGICIDES, NEMATICIDES, AND INSECTICIDES FROM SEED COAT TO TARGET REGION IN COTTON PRODUCTION

摘要

Seed treatments have become an important tool in the management of early season pest in cotton. One of the main attributes in selecting an active ingredient (ai) or formulation as a potential seed treatment candidate is the ability of the active ingredient to move from the seed coat to other target regions (seed, soil, roots, hypocotyls and leaf tissue). There are several tools used to determine the movement of ai's from the seed coat to target regions. First, physiochemical information about the active ingredient (water solubility, vapor pressure, partition coefficient, adsorption and half-life) that is needed to register a formulation with EPA coupled with plant uptake information (systemic or non-systemic) gives a researcher many tools to explainthe movement of a seed treatment. Another useful tool, if not the most important, is the bio-efficacy information. Does the seed treatment formulation control the pest in question? In this review, the emphasis was on the use of radiolabelled studies (C14 ) that showed the movement of seed treatment chemicals from the seed coat to target regions. C14 studies that utilized the following active ingredients, thiamethoxam, mefenoxam, azoxystrobin, and abamectin, were used to show the movement of ai's in soil, roots, hypocotyls, cotyledons and leaf tissue. This technique can be used to visually show the movement of a seed treatment chemical from the seed coat to target regions and can be used to quantify the amount of active ingredient within each region. Utilization of physiochemical properties, bio-efficacy results and radiolabelled studies are useful tools in explaining the mechanism by which seed treatments move from the seed coat to target regions.