Acute and sublethal toxicity of novaluron, a novel chitin synthesis inhibitor, to Leptinotarsa decemlineata (Coleoptera: Chrysomelidae)

Abstract

The acute and sublethal toxicities of novaluron, a novel chitin synthesis inhibitor, to a laboratory-reared insecticide-susceptible strain of Colorado potato beetle, Leptinotarsa decemlineata (Say), were determined. Novaluron exhibited excellent residual (120 h LC(50) = 0.42 mg litre(-1)) and good direct contact (120 h LC(50) = 27 mg litre(-1)) activity against second-instar larvae (L2). Hatch of eggs exposed by direct contact to novaluron solutions > or =100 mg litre(-1) was significantly reduced, as was the ability of emerged first-instar larvae to moult. L2 from eggs exposed to > or =100 mg litre(-1) novaluron weighed significantly less (P < 0.0001) than those from untreated eggs. However, L2 from eggs treated with 1 mg litre(-1) novaluron weighed significantly more (P < or = 0.05) than those from untreated eggs, suggesting novaluron can have a hormetic effect on L decemlineata larval development. Leptinotarsa decemlineata mating pairs fed foliage treated with novaluron at 25 or 75 g AI ha(-1) produced approximately 25% fewer egg masses and eggs per mass. Hatch of eggs on treated foliage was almost completely suppressed, and longevity of male beetles was reduced by approximately 50% when fed foliage treated with novaluron at 75 g AI ha(-1).

Effect of Some Integrated Pest Management Elements on the Population Density of Bemisia Tabaci (Gennadius) (Hemiptera: Aleyrodidae) on Tomato Plants (Solanum Lycopersicum L.)

“…They found that all tested insecticides were comparable against B. tabaci nymphs, and both of thiamethoxam and acetamiprid achieved the highest reduction percentage in two consecutive seasons. The present results show that the chitin synthesis inhibitors (pyriproxyfen and Buprofezin) were effective against B. tabaci nymphs in agreement with both of Lee et al, (2002) and Cutler et al, (2005) who found that the insect growth regulator, pyriproxyfen and novaluron were effective against immature stages of B. tabaci and relatively low effective against the adult stage. In general, the current results recommended to use sulfoxaflor or thiamethoxam insecticides or in a sequential treatment with chitin inhibitors, at the proper diurnal activity of B. tabaci to control the pest, beside the use appropriate plant spacing and the better rates of chemical fertilizers (NPK)…”

Toxicity of Insecticides on Various Life Stages of Two Tortricid Pests of Cranberries and on a Non-Target Predator

“…parallela eggs, but weak adulticidal activity and moderate larvicidal, particularly on 1st instars, activity. Ovicidal activity of novaluron has been shown for lepidopteran (e.g., [ 36 , 45 ]), and coleopteran (e.g., [ 46 , 47 ]), pests. The use of the IGR novaluron as an ovicidal-larvicidal insecticide, as well as neonicotinoids, in cranberries may be limited by their potential toxicity to bees (e.g., [ 48 , 49 , 50 ]).…”

Novaluron Causes Reduced Egg Hatch After Treating Adult Codling Moths,Cydia pomenella: Support for Transovarial Transfer

“…Similar delayed lethal effects of novaluron have been seen in other key pests, but the exact mechanism is unknown. Transovarial movement of the compound from the exposed adult to their eggs and larvae is one mechanism that has been suggested (Cutler et al 2005; Kostyukosky and Trostanetsky 2006; Wise et al 2007; Alyokhin et al 2008). A second suggested explanation for novaluron's activity is the horizontal transfer from contaminated tarsi or scales of previously exposed adults to unexposed eggs, which has been documented with another insect growth regulator (pyriproxyfen) against mosquitoes (Chism and Apperson 2003).…”