Diflubenzuron

Eisler, R. 1992. Diflubenzuron hazards to fish, wildlife, and invertebrates a synoptic review. U.S. Fish Wildl. Sen. Biol. Rep. 4, 36 pp. 

Eisler, R. 2000. Diflubenzuron. Pages 983-1019 in Handbook of Chemical Risk Assessment Health Hazatds to Humans, Plants, and Animals. Volume 2, Organics. Lewis Publishers, Boca Raton, Flmda. 

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Many pesticides cause endocrine disruption in vertebrate and invertebrate species at concentrations that are not overtly metabolically toxic. The insect growth inhibitor diflubenzuron can affect the reproduction, development and behaviour of estuarine crustaceans at concentrations of just lOmgP (reviewed... 

Diflubenzuron effects on selected aquatic organisms laboratory studies... 

Diflubenzuron breakdown by hydrolysis, soil degradation, or plant and animal metabolism initially yields 2,6-difluorobenzoic acid and 4-chlorophenylurea. Ultimately, the end products are... 

Figure 17.1 Generalized degradation pattern for diflubenzuron. Diflubenzuron (A) degrades initially to 2,6-difluorobenzoic acid (B) and 4-chlorophenylurea (C). 2,6-Difluorobenzoic acid (B) degrades to 2,6-difluorobenzamide (D) and 4-chlorophenylurea (C) degrades to 4-chloroaniline (E).

Mobility and leachability of diflubenzuron in soils is low, and residues are usually not detectable after 7 days. In water, half-time persistence (Tb 1/2) is usually less than 8 days and lowest at elevated temperatures, alkaline pH, and high sediment loadings (Fischer and Hall 1992) (Table 17.2). Increased concentrations of diflubenzuron in soils and waters are associated with increased application frequency, flooding of treated supratidal areas, wind drift, and excessive rainfall (Cunningham 1986). 

The presence of sediments in diflubenzuron marine microcosms results in rapid removal from seawater and ultimately a reduction in mortality of larval crustaceans (Table 17.2) (Cunningham et al. 1987). But marine sediments that exceed 200 pg diflubenzuron/kg — levels normally encountered at application rates for control of salt marsh mosquitoes — could be detrimental to juvenile and adult crustaceans that consume detritus and organic matter on the surface of the marsh or at the water-sediment interface (Cunningham and Myers 1986 Cunningham et al. 1987). 

Table 17.2 (continued) Diflubenzuron Persistence in Soil and Water... 

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