The possibility of PYRIPROXYFEN electrochemical detection in water (in neutral, or alkaline pH conditions) has been studied. During the analysis, piriproxyfen is transformed in a yet studied quinone-hydroquinonic system before the electrochemical reaction. By means of mathematical model development and analysis, using the linear stability theory and bifurcation analysis, the analytical efficiency conditions have been detected, including the optimal pH and potential range. The oscillatory and monotonic instability conditions have also been detected. These instabilities may be caused by double electric layer influences of the electrochemical reaction. The analysis may be driven in the presence of different organic, hybrid and inorganic modifiers. Nevertheless, the specific conditions for electrode modifying material stability are required for the electrochemical analysis of piriproxyfen.

Objective(s): PYRIPROXYFEN as an insect growth regulator is widely used globally for pest management. There are reports on adverse effects of insecticides such as organ toxicity, endocrine disruptions, and teratogenicity in animals and humans. We aimed to investigate reproductive toxicity of PYRIPROXYFEN in adult male mice. Materials and Methods: 48 male Swiss albino mice were divided into eight groups and received the different 1200, 600, 320, 200, 100, 40, 20, 0 mg/kg/day doses orally, and body weights were accessed for 28 consecutive days. In the end, mice were sacrificed, testes were dissected and weighed. Probable testicular tissue alterations were examined by histopathological studies. In addition, the diameter of seminiferous tubules and Leydig cells distribution were assessed in all experimental and control groups. Results: PYRIPROXYFEN treatment caused significant (P<0. 05) reduction in body and organ weights in mice. However, the shrinkage and displacement of seminiferous tubules, reduced lumen diameter, and vacuolization occurred in seminiferous tubules in higher doses exposed animals in comparison to controls. The relative testis weights, mean diameter of seminiferous tubules, and Leydig cells distribution remained unchanged at low doses. Conclusion: These findings reveal that PYRIPROXYFEN caused reduction in body weight gain as well as damage to the testicular architecture in mice and thus may potentially interfere with spermatogenesis. Findings in an outbred strain of mice can be extrapolated fairly reliably to the human model. The chemical can thus be further exploited to study its effects on impairment of fertility and as an endocrine disruptor.

Bumblebees are valuable assets in terms of pollination services in wild plants and greenhouses. The most well-studied species of bumblebees is Bombus terrestris which is commercially reared and sold on a large scale worldwide. Even though the artificial rearing of bumblebees started in the 1950s, there are still some problems in the mass-rearing process of them. One of the main problems is the low rate of gyne production in the late phase of the colony, to start the new colonies. So, the main objective of this study was to increase the number of produced gynes in the B. terrestris colonies by changing the caste of the larva from worker to queen. For this purpose, we used PYRIPROXYFEN which is a juvenile hormone analogue compound. The first and early second-stage larvae were treated with 1,3 and 6 ppm of PYRIPROXYFEN and the onset time of emergence, number, weight, mating succession, and diapause survival of new gynes were recorded. The results showed that the 3 ppm treatment had the highest number of the produced gynes, and also the shortest onset time of emergence. There was no difference in mating succession and diapause survival among the treatments. Based on the experiment results, we concluded that using a 3 ppm concentration of PYRIPROXYFEN compound on young larvae of B. terrestris can induce the juvenile hormone effect and increase the number of produced gynes in the colony. We suggest that PYRIPROXYFEN as a juvenile hormone analogue, regarding the concentration, type, and time of application on the young larvae, can be used to increase the number of produced gynes in the bees’ colony.

Possible effects of a synthetic juvenoid hormone (PYRIPROXYFEN) on larval development, metamorphosis and survival of a crustacean octapod, Macrobrachium rosenbergii, was studied. Although Pyriproxifen is well known as an effective pest control product, our knowledge about its effects on crustacean metamorphosis, especially on larval stages is yet little. Macrobrachium rosenbergii is a suitable invertebrate species in the neurobiological and endocrinological researches. The species has 11 larval stages with obvious morphological features for every stage.In this study, larvae of the species were treated with 0.01, 0.05 and 0.1ppm of Pyriproxifen against a group of control for which xylene was used. In the first day of exposure to the Pyriproxifen, all larvae were in the 1st larval stage. We studied the larval stages in samples obtained in different days and percentage of survival in the end of metamorphosis for treatment and control groups. The results showed that all concentrations of PYRIPROXYFEN significantly caused a delayed larval development and metamorphosis. Furthermore, the post larval survival rates of all treatment groups were less than control.These results suggest that synthetic juvenoid hormone retards the larval morphological development in Macrobrachium rosenbergii, and decreases the survival of the species.

The lady beetle Adalia decempunctata L. (Col.: Coccinellidae) is known as the ten-spotted ladybeetle, whose larvae and adults are active hunters. These insects have been reported from several stone-fruit trees, seed-fruit trees, broad leaved forest trees and coniferous forest trees infested with pests like aphids, mealybugs and psyllid from several countries on the world. The culture of this predator was maintained in laboratory condition (25 ± 2 º C, 75 ± 5% RH and 16: 8h L: D). In this research, the bioassays of PYRIPROXYFEN was performed through topical application method. The concentration of IC10, IC30, IC50 and IC90 were estimated 18. 6, 33. 1, 49. 3 and 130. 6 μ g/ml, respectively. Also, in order to have a better understanding, some of the most important biochemical parameters were evaluated in the 4th instar larvae treated with sublethal concentrations of PYRIPROXYFEN. The results showed that lipid and protein amount were relatively increased compared to control, while the glycogen amount was reduced in treated larvae. The activity of detoxifying enzymes (Glutathione S-transferase and general esterases) in treated larvae were significantly increased compared to control. The activity of peroxidase was also increase significantly compared to controls. As the PYRIPROXYFEN is a juvenile hormone analogue, therefore the growing stages of this predator is affected. While adults that have surpassed this stage are no longer dependent to growth hormones and are less affected. Hence, supplementary evaluation of the use of PYRIPROXYFEN and this predator at the same time under field conditions is needed.

Chemical control is one of the important strategies in agricultural pest management because of easy operation, availability and fast control of pests. On the other hand, the environment has been exposed to various types of pesticides and pollutants which are growing daily. The persistent effects of residual pesticides commonly used cause numerous problems for non-target organisms especially parasitoids and predators. In this research, the effects of PYRIPROXYFEN and imidacloprid on Cheilomenes sexmaculata (F. ) (Coleoptera: Coccinellidae) were studied. The eggs of the ladybird beetle were treated with each pesticide in three concentrations by dipping method. Maximum field recommended concentration (MFRC=50 mg/L), 2/1 MFRC (to simulate multiple treatments) and 1/2 MFRC (to test the sublethal effects) were used for PYRIPROXYFEN and 1/1 MFRC (140 mg/L), 1/2 MFRC (70 mg/L) and 1/4 MFRC (35 mg/L) were used for imidacloprid. The highest mortality of the first instar larvae was observed in imidacloprid at MFRC and PYRIPROXYFEN at 2/1 MFRC. Also, maximum influence on fertility was observed at 2/1 MFRC of PYRIPROXYFEN and MFRC of imidacloprid with 55% and 44% reduction compared to the control, respectively. Moreover, PYRIPROXYFEN caused significant retardation on larval development at concentrations higher than 1/2 MFRC. Both insecticides initiated a significant effects on adult eclosion compared to the control and the greatest influence was observed by imidacloprid at 1/1 MFRC with 89% reduction in adult eclosion. Although results revealed that imidacloprid has higher acute toxicity to C. sexmaculata, further results obtained from the analysis of on the life cycle parameters of C. sexmaculata also indicated that PYRIPROXYFEN also had toxic effects on this predator.

Background: The residual effect of triflumuron and PYRIPROXYFEN on Musca domestica L larval stages was studied in the laboratory.Methods: Both IGRs at varying concentrations ranging between 0.5 to 2.5 mg/L were placed inside beakers with mice chow and vitamin B complex and water as food for the 1st, 2nd and 3rd instars M.domestica larvae. Results: Both IGRs inhibit M. domestica adult emergence of 98-98.5% when applied at the lowest concentration of 0.5 mg/L on the 1st instar, 93-97% of adult emergence inhibition on the 2nd instar, and 91-97% of adult emergence inhibition on the 3rd instar larvae respectively. There was no significant difference between triflumuron and PYRIPROXYFEN on housefly adult emergence inhibition when fed to the 1st, 2nd and 3rd instars M.domestica larvae (P> 0.05). However, there was a significant difference between the IGRs and the control (P< 0.05).Conclusion: Both triflumuron and PYRIPROXYFEN are effective in inhibiting adult emergence of housefly M domestica and therefore should be recommended for fly control particularly in chicken farms and dumping grounds in Malaysia for housefly control activities.

Background and ObjectivesThe widespread Mediterranean flour moth, Ephestia kuehniella (Zeller), causes economic damage by feeding on stored products, particularly cereal flour. PYRIPROXYFEN is one of the most significant insect growth regulators widely used in controlling stored-product insect pests due to its low toxicity to mammals and lack of dangerous residues in food. By imitating the action of juvenile hormone, PYRIPROXYFEN causes insect pests to experience prolonged larval development, failure to emerge as pupae or malformed pupae, absence of embryo development, and in some cases, a reduction in fecundity.Materials and MethodsThis study examined the toxicity of PYRIPROXYFEN on E. kuehniella fifth instar larvae at 25 ± 1°C, 65 ± 5% relative humidity, and a photoperiod of 16:8 (L:D) h. The 50% lethal concentration (LC50) of the insecticide was calculated as 7.39 and 5.68 ppm at 72 and 96 h post-treatment, respectively. After preparing the desired concentrations based on the preliminary test using acetone solvent, the effect of sublethal concentrations (LC20 = 2.87, LC30 = 4.10, and LC40 = 5.56 ppm) of PYRIPROXYFEN on mortality and survival period of fifth instar larvae was investigated.ResultsThe results of this study demonstrated that the survival period of larvae treated with LC20 (35.05 days) was significantly longer than the control group (18.85 days). One week after exposure to sublethal concentrations of PYRIPROXYFEN, the larvae's survival rate was significantly lower than the control group. However, the survival percentage of larvae at two- and three-weeks post-treatment was not significantly different from the control.DiscussionOne of the possible explanations for the shorter survival period of larvae treated with LC30 and LC40 is the greater toxicity of these concentrations against the pest and, consequently, the increase in the percentage of larval mortality in the second- and third-weeks following treatment. This study found that sublethal concentrations of PYRIPROXYFEN could be used to control the Mediterranean flour moth under storage conditions.