Chemical residues and bioactivity of tebufenozide applied to apple foliage

Abstract

Tebufenozide, an insect growth regulator that acts as an ecdysone agonist, was applied at recommended label rate to apple trees in August 1997 and May 1998. Foliar residues were determined by high-performance liquid chromatography from samples collected 2, 24, 48 and 96 h post-spray, and at weekly intervals thereafter for 9 weeks in 1997 and 11 weeks in 1998. Foliage sampled at the same times was used in bioassays to determine residual toxicity to first-instar obliquebanded leafrollers, Choristoneura rosaceana (Harris). Residue decay followed first-order kinetics in both years, with residual half-life of 36.3 days in 1997 and 7.2 days in 1998. Estimates of the time needed to reduce bioactivity to 50% in bioassays were 18.7 days in 1997 and 36.3 days in 1998. The accuracy of equations describing decay of tebufenozide residues and bioactivity over time was not improved by using degree-day accumulations as the independent variable.

Control of Grape Berry Moth (Lepidoptera: Tortricidae) in Relation to Oviposition Phenology

“…The long activity period of methoxyfenozide observed in this study was similar to that found with other diacylhydrazines and IGRs. It seems that this residual activity is based on persistence of insecticide residue on treated plants and not on sublethal effects of insecticide applied against a previous generation (Smirle et al 2004, Borchert et al 2005, Pavan et al 2005. Therefore, residue dilution on plant surface by factors such as temperature, UV light, rainfall, and plant growth will interact with pest phenology to determine the duration of efÞcacy of methoxyfenozide.…”

“…Residual half-life of tebufenozide concentration on apple (Malus spp.) leaves was 7.2 and 36.3 d in May and August, respectively, and the estimated time needed to decrease bioactivity by 50% was 36.6 and 18.7 d, respectively (Smirle et al 2004). The long residual activity of diacylhydrazine insecticides indicates that the management strategy traditionally used with conventional insecticides, such as multiple insecticide applications throughout the season, could be modiÞed.…”

Long‐term foliar persistence and efficacy of spinosad against beet armyworm under greenhouse conditions

“…It is well known that leaf age and environmental conditions influence the persistence, and consequently the efficacy, of any chemical insecticide 30, 31. In particular, photolysis is the main responsible factor of a rapid breakdown of spinosad in the environment 13.…”

Synthesis, Crystal Structure, DFT Study of m-Methoxy-N′-(3-Methoxybenzoyl)-N-Phenylbenzohydrazide

“…The diacylhydrazine insecticide family shows efficacy against lepidopteran larvae in the field and laboratory [6]. Tebufenozide and its methoxylated derivative methoxyfenozide present intrepid activity as agonists or mimic the insect molting hormone 20-hydroxyecdynose by inducing premature, incomplete ecdysis, resulting in the death of the exposed insects [7][8][9][10][11].…”