Laboratory Evaluation of Five Chitin Synthesis Inhibitors Against the Colorado Potato Beetle,Leptinotarsa decemlineata

Abstract

Results of laboratory experiments are reported that tested the effects of five chitin synthesis inhibitors, diflubenzuron, cyromazine, lufenuron, hexaflumuron and triflumuron. on second instars of the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Crysomelidae), originally collected from potato fields of Bostanabaad, a town 66 km southeast of Tabriz, Iran. In bioassays, the larvae were fed potato leaves dipped in aqueous solutions containing chitin synthesis inhibitors. The mortalities and abnormalities of the treated larvae were recorded 72 hours after treatments. LC50 values were 58.6, 69.6, 27.3, 0.79 and 81.4 mg ai/ L for diflubenzuron, cyromazine, lufenuron, hexaflumuron and triflumuron, respectively. Compared with phosalone, which is one of the common insecticides used for controlling this pest in Iran, lufenuron and hexaflumuron seem to be much more potent, and if they perform equally well in the field, they would be suitable candidates to be considered as reduced risk insecticides in management programs for L. decemlineata due to much wider margin of safety for mammals and considerably fewer undesirable environmental side effects.

Evaluation of Two Formulated Chitin Synthesis Inhibitors, Hexaflumuron and Lufenuron Against the Raisin Moth,Ephestia figulilella

“…These larvae were not able to feed, and eventually died. These results are consistent with results of Hughes et al (1986) and Karimzadeh et al (2007). Molting and metamorphosis are two critical physiological events in the life of insects.…”

“…It may be concluded from these results that E. figulilella is more sensitive to hexaflumuron than lufenuron. Karimzadeh et al (2007) rated the toxicity of five different chitin synthesis inhibitors in the following order: hexaflumuron > lufenuron > diflubenzuron > triflumuron > cyromazine. Saenz-de-Cabezon et al (2006) found significant effects of lufenuron against different larval instars of L. botrana .…”

“…In most of the studies that have been conducted on the effects of these two pesticides, hexaflumuron has been found to be more effective against the same pest than lufenuron. For example, results of Karimzadeh et al (2007) indicated that among the chitin synthesis inhibitors tested, hexaflumuron and lufenuron (with LC 50 values of 0.79 and 27.3 mg ai/L respectively) were the most effective at low concentrations against the Leptinotarsa decemlineata . These results show that L. decemlineata is 34.5 times more sensitive to hexaflumuron than it is to lufenuron.…”

Biological efficacy of some biorational and conventional insecticides in the control of different stages of the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae)

“…In addition to potato, it devastates, by its voracious feeding, other solanaceous crops such as eggplant, tomato, pepper, and tobacco (Radcliffe 1982;Hare 1990;Metcalf & Metcalf 1993;Phyllis 2004). L. decemlineata can completely defoliate plants prior to tuber formation if not adequately controlled (Koopmanschap et al 1989;Zehnder & Evanylo 1989;Nault & Kennedy 1998;Karimzadeh et al 2007), and may reduce tuber yields by as much as 50% (Hare 1980). Moreover, this pest is widely considered as a quarantine pest in most countries of the world including Egypt (EPPO 2006).…”

Scanning Electron Microscopy and Biochemical Studies on Spodoptera littoralis Larvae Following Treatments with Ethanolic Extract of Taxodium distichum and Lufenuron

“…This plant is known to produce a range of terpinoids, flavonoids and pyrons. Karimzadeh et al (2007) Effects of five chitin synthesis inhibitors, diflubenzuron, cyromazine, lufenuron, hexaflumuron and triflumuron, on 2 nd instars of Leptinotarsa decemlineata. lufenuron and hexaflumuron seem to be more potent.…”