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|Title:||The isolation and characterization of common lambsquarters cuticles and the effect neodol surfactants on the penetration of bentazon and glyphosate|
|Author(s):||Bergman, Daniel Lee|
|Doctoral Committee Chair(s):||Liebl, Rex A.|
|Department / Program:||Agriculture, Agronomy|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||An isolation procedure was developed to isolate annual weed cuticles unattainable with previous techniques. The technique takes advantage of the feeding behavior of (Chrysoesthia lingulacella Clemens), a microlepidopteran leaf miner. Cuticles of common lambsquarters (Chenopodium album L.) were isolated by the leaf miner technique. Electron micrographs verified the successful isolation of leaf cuticles, which include epidermal cells, without structural alterations of the adaxial and abaxial surfaces. Penetration of bentazon through isolated cuticles was monitored using a cuticle penetration apparatus developed to conserve the effects of droplet drying on penetration. Greater bentazon penetration was observed through the lower leaf surface compared to adaxial leaf surface.
The performance of four Neodol$\sp\circler$ linear alcohol surfactants in combination with bentazon or glyphosate herbicides were evaluated by cuticle penetration and whole-plant studies using common lambsquarters plants. Penetration of bentazon and glyphosate using the in vitro leaf miner cuticle isolation technique increased with increasing ethylene oxide (EO) content of surfactant; 12 EO $>$ 6.5 EO $>$ 5 EO $>$ 3 EO. Whole-plant greenhouse studies using glyphosate showed the same trend in surfactant effectiveness, suggesting that surfactant performance on the whole-plant level can be adequately predicted using the in vitro cuticle penetration technique. Whole-plant field and greenhouse trials using bentazon, however, yielded few differences in surfactant activity. The reason for the lack of similarity between whole-plant and isolated cuticle studies using bentazon was not investigated.
Bentazon penetration through isolated common lambsquarters cuticles was greater under high relative humidity (HRH) 81% than low relative humidity (LRH) 1%. Under both conditions surfactant effectiveness increased with increasing ethylene oxide (EO) content. Droplet drying times of surfactant/herbicide solutions were longer for HRH compared to LRH and drying time also increased with increasing EO of the surfactant. Results suggest that a herbicide droplet remaining as a liquid on the leaf surface for a longer period of time results in greater bentazon penetration. From these data it appears that increased herbicide penetration with increasing surfactant EO content and/or HRH may be due in part to the reductions in droplet drying, resulting in increased time for diffusion and possibly greater hydration of the "dried" droplet deposit.
|Rights Information:||Copyright 1992 Bergman, Daniel Lee|
|Date Available in IDEALS:||2011-05-07|
|Identifier in Online Catalog:||AAI9305466|