Novaluron

Novaluron is a chemical with pesticide properties, belonging to the class of insecticides called insect growth regulators.

Effects of residual novaluron on reproduction in alfalfa leafcutting bees, Megachile rotundata F. (Megachilidae).[Pubmed:27405042]

Pest Manag Sci. 2017 Jan;73(1):153-159.

BACKGROUND: The chitin synthesis inhibitor Novaluron can suppress pests that affect alfalfa seed production, but can negatively affect reproductive success in the alfalfa pollinator Megachile rotundata. Novaluron is considered to be a reduced-risk insecticide because it disrupts ecdysis and is non-lethal to adult insects, but some exposed adults have fewer eggs and suppressed egg hatch. For this experiment, bees nested in field cages where they were exposed to alfalfa that had never been treated with Novaluron, alfalfa that had recently been sprayed or alfalfa that had been sprayed 1 and 2 weeks earlier. RESULTS: Compared with the control, greater proportions of dead eggs and larvae and lower proportions of live prepupae occurred when bees were exposed to recent Novaluron sprays as well as one- or two-week old spray residues. Two possible routes of residual pesticide exposure were revealed. Mother bees become contaminated through ingestion or direct contact, or pollen-nectar provisions become contaminated with Novaluron (1) on or within leaf pieces that surround provisions or (2) transferred from mother bees' bodies to provisions. CONCLUSION: We found strong immature mortality effects of Novaluron and its residues on M. rotundata. Understanding all possible pesticide exposure routes for pollinating bees enhances decision-making for maintaining bee populations while protecting crops. (c) 2016 Society of Chemical Industry.

Baseline Susceptibility of Lygus lineolaris (Hemiptera: Miridae) to Novaluron.[Pubmed:26546489]

J Econ Entomol. 2016 Feb;109(1):339-44.

Tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), populations were collected from field locations in the Mississippi River Delta of Arkansas, Louisiana, and Mississippi. Third-instar F(1) nymphs from each field location, in addition to a laboratory colony, were screened for susceptibility to Novaluron. Both a glass vial bioassay and a diet-incorporated bioassay used dose-response regression lines to calculate LC(50) and LC(90) values for Novaluron. Mean LC(50s) for glass vial bioassays ranged from 44.70 +/- 3.58 to 66.54 +/- 4.19 mug/vial, while mean LC(50s) for diet-incorporated bioassays ranged from 12.10 +/- 0.77 to 17.63 +/- 2.42 mug/200 ml of artificial diet. A comparison of LC(50) values from the same field population screened using both bioassay methods failed to show a relationship. LC(50) values from field locations were compared with a historically susceptible population from Crossett, AR. Results indicated that considerable variability in susceptibility to Novaluron exists within field populations of tarnished plant bugs across the Delta, including some locations with lower LC(50) values than a historically susceptible population.

Chronic and acute risk assessment of human exposed to novaluron-bifenthrin mixture in cabbage.[Pubmed:27550439]

Environ Monit Assess. 2016 Sep;188(9):528.

Based on the dissipation and residual level in cabbage determined by gas chromatography coupled with an electron capture detector (GC-ECD), chronic and acute risk assessments of the Novaluron and bifenthrin were investigated. At different spiked levels, mean recoveries were between 81 and 108 % with relative standard deviations (RSDs) from 1.1 to 6.8 %. The limit of quantification (LOQ) was 0.01 mg kg(-1), and good linearity with correlation coefficient (>0.9997) were obtained. The half-lives of Novaluron and bifenthrin in cabbage were in the range of 3.2~10 days. Based on the consumption data in China, the risk quotients (RQs) of Novaluron and bifenthrin were all below 100 %. The chronic and acute risk of Novaluron in cabbage was relatively low, while bifenthrin exerts higher acute risk to humans than chronic risk. The obtained results indicated that the use of Novaluron-bifenthrin mixture does not seem to pose any chronic or acute risk to humans even if cabbages are consumed at high application dosages and short preharvest interval (PHI).

Susceptibility of Rhipicephalus (Boophilus) microplus to fluazuron (2.5mg/kg) and a combination of novaluron (2.0mg/kg)+eprinomectin (0.36mg/kg) in field studies in Brazil.[Pubmed:27931932]

Prev Vet Med. 2016 Dec 1;135:74-86.

The present study aimed to determine the susceptibility of 32 R. (B.) microplus populations from Southeast, Midwest and South regions of Brazil, to fluazuron (2.5mg/kg), administered topically (pour-on). Additionally, five populations (Southeast and Midwest regions) of the southern cattle tick were evaluated using in vivo field studies, regarding their susceptibility to a new combination of Novaluron (2.0mg/kg)+eprinomectin (0.36mg/kg), administered subcutaneously, compared with two positive controls (fluazuron 2.5mg/kg and eprinomectin 0.5mg/kg), both administered topically (pour-on). Selected bovines were allocated to treatment groups on day 0, and block formation was based on arithmetic means of female ticks (4.5-8.0mm long) counted on three consecutive days (-3, -2 and -1). To evaluate therapeutic and residual efficacies of these formulations, tick counts (females ranging from 4.5 to 8.0mm long) were performed on days 3, 7 and 14 post-treatment, continuing on a weekly basis until the end of each experiment. Results obtained throughout this study, utilizing field efficacy trials, allowed us to conclude that four R. (B.) microplus populations (including two in the Southeast and two in the Midwest regions) could be diagnosed as resistant, or with low susceptibility, to fluazuron (2.5mg/kg). Such fact was detected in farms where owners applied products containing this active component on cattle for at least five years, with treatment intervals of 30-55days during the rainy season. Nonetheless, in vitro studies should be performed in order to reinforce in vivo results obtained on the present study. Regarding efficacy indexes obtained by the association of eprinomectin and the novel molecule Novaluron against R. (B.) microplus, none of the trials managed to obtain efficacies superior to 48%. Such results, allied to data obtained by different researchers and previously published in literature, reinforce the perception that maybe these formulations containing Novaluron, in the administered dosages and treatment routes, may not be effective tools for controlling R. (B.) microplus. However, future studies must be conducted in order to support such hypothesis. Additionally, all five R. (B.) microplus populations were diagnosed as resistant, or with low susceptibility, to eprinomectin (0.5mg/kg) as well. Even though fluazuron, administered topically (pour on), is still an excellent active principle to be used against R. (B.) microplus, resistance management strategies should be quickly implemented in order to keep selection pressure in Brazil at a minimum level for this compound.