Herbicidal Activity of IVG and IVH

The herbicidal activity of IVG and IVH evaluated by Petri dish methods and in the greenhouse. The results are reviewed as follows. 

1 Herbicidal Activity of 4-[(Substituted Phenoxyacetoxy)Methyl]-2,6,7-Trioxa-l-Phosphabicyclo[2.2.2]Octane-l-One IVG 

As a preliminary bioassay, fifteen caged bicyclic phosphates IVG were tested for inhibitory activity against barnyard grass (E. crusgalli) and cabbage type rape (B. napus) using the Petri dish methods. The inhibitory effect of IVG on the growth of roots and stems of plant were examined. The results ate listed in Table 5.31. 

As shown in Table 5.32, IVG-2, IVG-4, and IVG-6 exhibited good post-emergence herbicidal activity against tested dicotyledonous plants, especially IVG-4 displayed a 100 % inhibition effect against all tested broad-leaved weeds at 150 g ai/ ha. However, there was no activity against monocot weeds. IVG-2, IVG-4, and IVG-6 will be further tested for their post-emergence herbicidal activity at a lower rate. 

However, caged bicyclic phosphates IVG with 2,4-Cl2 2-Me,4-Cl 3-Me,4-Cl 2-Cl,4-F 2-Cl 3-CF3 as Y on the phenoxy-benzene ring displayed better inhibitory effect at 100 and 10 mg/L against the growth of roots of tested plant than other substitutions. It showed the influence of Y on post-emergence herbicidal activity was different from the influence of Y on pre-emergence herbicidal activity. 

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