Herbicidal Activity of IVC-IVF

As mentioned in Chap. 2, several series of open-chain 1-(substituted phenoxy-acetoxy)aLkylphosphonates were found to exhibit notable herbicidal activity against dicotyledons. In order to examine the effect of phosphorus-containing heterocyclic moiety on herbicidal activity, a phosphorus-containing six-member ring was introduced into different molecules to form cyclic phosphonates IVC-IVF. A set of experiments were performed to evaluate their herbicidal activity. The herbicidal activity of cyclic phosphonates IVC-IVF are reviewed as follows. 

I Herbicidal Activity of 2-[I-(Substituted Phenoxyacetoxy)Alkyl]-5,5-Dimethyl-I,3,2-Dioxaphosphinane-2-One IVC 

As shown in Table 5.13, IVC-I6-23 displayed good inhibitory effect ( 90 %) on the growth of roots of cabbage type rape and barnyard grass at 100 and 10 mg/L. They will be further examined for their pre-emergence herbicidal activity in the greenhouse. 

Cyclic phosphonates IVC-2 and IVC-7-23 exhibited 61-83 % inhibitory activity against the growth of the stem of cabbage type rape, but most cyclic phosphonates IVC showed 60 % inhibitory activity against the growth of the stem of barnyard grass except IVC-18 and IVC-20 with 66 and 60 inhibitory effect at 10 mg/L. 

Cyclic phosphonates IVC-I5, IVC-I6, IVC-18, and IVC-I9 were selected for further bioassay at a lower rate for post-emergence herbicidal effect and clacyfos (IC-22, HW02) was used as a positive control. The results are listed in Table 5.15. 

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