Search Results (10)

Aphis gossypii (Glover) (Hemiptera: Aphididae) is a significant pest in cotton fields, and the use of both chemical insecticides and natural enemies is a crucial strategy for its management. Hippodamia variegata (Goeze) (Coleoptera: Coccinellidae), a predominant predatory natural enemy in cotton fields, plays a vital role in controlling A. gossypii populations. In this study, we investigated the toxicity of four insecticides to both A. gossypii and H. variegata larvae, assessed their field efficacy against A. gossypii, and evaluated their effects on the predatory function of H. variegata larvae. The results revealed that afidopyropen and spirotetramat exhibited relatively high toxicity against A. gossypii, with LC₅₀ values of 13.18 mg/L and 22.17 mg/L, respectively. Flonicamid demonstrated the least toxicity to H. variegata larvae, with an LC₅₀ of 512.66 mg/L. The selectivity toxicity ratios for afidopyropen and flonicamid were 5.05 and 4.73, respectively, indicating strong, favourable selectivity towards H. variegata. The maximum field control efficacy against A. gossypii was 96.76% for afidopyropen and 96.92% for flonicamid. The reduction rates of H. variegata larvae in the afidopyropen treatment plots were relatively low. Among the four treatments, the theoretical predation of third-instar H. variegata larvae against A. gossypii was highest with flonicamid, reaching 215.67. Overall, the four insecticides differed substantially in their combined effects on aphid suppression and predator performance. In particular, afidopyropen and flonicamid provided excellent control of A. gossypii while showing comparatively lower toxicity to H. variegata and causing less impairment of its predatory capacity, indicating a more favourable biological trade-off between pest control and natural enemy conservation. However, laboratory toxicity and functional response assays may not fully capture predator–prey dynamics under complex field conditions; therefore, afidopyropen and flonicamid may be considered suitable candidate insecticides for inclusion in integrated pest management (IPM) programs in cotton systems. Full article

Myzus persicae Sulzer (Hemiptera: Aphididae) is a pivotal pest affecting various vegetables, fruits, crops, and ornamentals. The primary M. persicae management strategy involves insecticide use. In this study, the toxicity and efficacy of bifenthrin, fenitrothion, fosthiazate, acetamiprid, spirotetramat, afidopyropen, and flonicamid against M. persicae were evaluated under laboratory and greenhouse conditions using the leaf dip method. Laboratory bioassay results revealed that M. persicae exhibited susceptibility to moderate resistance levels for bifenthrin [resistance ratio (RR): 3.00–21.50], fenitrothion (3.13–25.31), fosthiazate (3.00–20.00), and acetamiprid (2.00–14.50), as well as susceptibility to low resistance levels for spirotetramat (0.75 to 6.63). Additionally, M. persicae was susceptible to flonicamid (0.31–1.72) and afidopyropen (0.67–2.00). Furthermore, laboratory bioassays revealed that the Al-Dhabia M. persicae field population showed the highest resistance levels to all tested insecticides compared with other tested field populations, which guided the examination of insecticide field performance under greenhouse conditions. In the greenhouse, most insecticides demonstrated high efficacy (>90%) against M. persicae with enduring effects, except for bifenthrin, which began to lose effectiveness 10 days post-application. In conclusion, M. persicae displayed overall susceptibility to most tested chemical classes, and the prolonged efficacy of these insecticides in the field reinforces their effectiveness in controlling this pest species. To maintain this control level, the registration of novel insecticides such as flonicamid and afidopyropen in Saudi Arabia is imperative, expanding the repertoire of effective chemical tools for M. persicae control. Additionally, a rotational approach to using all effective chemical classes is crucial to preventing or delaying resistance development in M. persicae. Full article

The tobacco whitefly, Bemisia tabaci MEAM1, is a destructive pest that damages plants by sucking plant juice and transmitting viruses. B. tabaci insecticide resistance contributes to population resurgence, and new insecticides are continually needed. Flonicamid and afidopyropen are selective pesticides with high insecticidal activity against piercing–sucking pests and safety to non-target species. We determined the toxicity of flonicamid and afidopyropen to B. tabaci, investigated the sublethal effects on life parameters, and studied physiological responses to them. Flonicamid and afidopyropen were highly toxic to B. tabaci, with LC₅₀ values of 12.795 mg/L (afidopyropen) and 25.359 mg/L (flonicamid) to nymphs and 4.711 mg/L (afidopyropen) and 11.050 mg/L (flonicamid) to adults. Sublethal concentrations (LC₁₀ and LC₂₀) reduced the longevity and fecundity of the B. tabaci F0 generation. Transgenerational effects were caused by exposure to sublethal concentrations of flonicamid and afidopyropen. Nymph mortality increased, development was delayed, fecundity decreased, and adult longevity was shortened. Population parameters such as the intrinsic rate of growth (r), net reproductive rate (R₀), and finite rate of growth (λ) were significantly decreased compared to the control. The activity of detoxifying enzymes, such as GSTs and P450, were induced by flonicamid and afidopyropen at 72 h, while CarE was inhibited. The expression levels of eleven P450 genes and four GST genes were significantly higher than in the control. In conclusion, flonicamid and afidopyropen have excellent acute toxicity and continuous control effects on B. tabaci. Higher GST and P450 activities and gene expression levels may play important roles in the detoxification metabolic process. Full article

The massive and repetitive application of synthetic insecticides for the management of cotton pests results in the accumulation of resistance in Aphis gossypii Glover, a destructive pest worldwide. New chemistries are needed for pest management. Afidopyropen exhibits high efficacy against piercing-sucking pests and has been applied as a complementary alternative insecticide against aphids. This study was conducted to investigate the lethal and sublethal effects of afidopyropen on the life parameters and physiological responses of A. gossypii. Detoxifying enzyme activities and expression levels of P450 genes were compared after exposure to three generations of afidopyropen. Bioassay results indicate that afidopyropen possessed the highest toxicity, with a LC₅₀ value of 0.30 mg/L. Sublethal concentrations (LC₅ and LC₁₀) caused adverse impacts on the F0 generation, reducing adult longevity and fecundity. A high concentration (LC₁₀) also caused adverse effects on the F1 generation, while a low concentration (LC₅) stimulated the fecundity. After continuous treatments with afidopyropen, the susceptibility decreased. GSTs and P450 were induced through sublethal concentrations; moreover, their activities in the F3 generation were higher than that in the F0 generation. Furthermore, the expression levels of 12 P450 genes in the F3 generation were higher than those in F0 generation. In conclusion, afidopyropen has excellent acute toxicity and continuous control effects on A. gossypii. GSTs and P450 may play important roles in the resistance of A. gossypii to afidopyropen. Full article

The resistance of cotton aphids to various forms of commonly used pesticides has seriously threatened the safety of the cotton production. Afidopyropen is a derivative of microbial metabolites with pyropene insecticide, which has been shown to be effective in the management of Aphis gossypii. Several field populations of Aphis gossypii were collected from the major cotton-producing regions of China from 2019 to 2021. The resistance of these populations to afidopyropen was estimated using the leaf-dipping method. The LC₅₀ values of these field populations ranged from 0.005 to 0.591 mg a.i. L⁻¹ in 2019, from 0.174 to 4.963 mg a.i. L⁻¹ in 2020 and from 0.517 to 14.16 mg a.i. L⁻¹ in 2021. The resistance ratios for all A. gossypii populations ranged from 0.03 to 3.97 in 2019, from 1.17 to 33.3 in 2020 and from 3.47 to 95.06 in 2021. The afidopyropen resistance exhibited an increasing trend in the field populations of Cangzhou, Binzhou, Yuncheng, Kuerle, Kuitun, Changji and Shawan from 2019 to 2021. This suggests that the resistance development of the cotton aphid to afidopyropen is inevitable. Therefore, it is necessary to rotate or mix afidopyropen with other insecticides in order to inhibit the development of afidopyropen resistance in field populations. Full article

Afidopyropen, a newly identified chemical, is a derivative of pyripyropene A, which is produced by the filamentous fungus Penicillium coprobium. It is a promising novel pesticide applied against whiteflies in agriculture. In this study, the reversion and selection, cross-resistance patterns, synergistic effects, and fitness costs of afidopyropen resistance were studied in a field-developed resistant population of B. tabaci. Compared to a reference MED-S strain, the field-developed resistant Haidian (HD) population showed 36.5-fold resistance to afidopyropen. Significant reversion of resistance to afidopyropen was found in the HD population when it was kept with no selective pressure of the insecticide. The HD-Afi strain, developed from the HD population with afidopyropen pressure, developed 104.3-fold resistance to afidopyropen and significant cross-resistance to sulfoxaflor. Piperonyl butoxide (PBO) largely inhibited afidopyropen resistance in the HD-Afi strain, which indicates that P450 monooxygenase could be involved in the resistance. Significant fitness costs associated with afidopyropen resistance were observed in HD-Afi. This study indicates that a rotation of afidopyropen with other chemical control agents could be useful for impeding afidopyropen resistance in B. tabaci. In addition, we expanded upon the understanding of resistance to afidopyropen, offering evidence suggesting the importance of devising better strategies for the management of whiteflies. Full article

Afidopyropen, a novel biopesticide, is derived from Aspergillus fumigatus, a fungus, and shows promise as a novel insecticidal agent for the management of the whitefly pest Bemisia tabaci in horticultural and economical crop production. In the present work, we monitored the susceptibilities of B. tabaci to afidopyropen in 18 field populations, sampled from 9 provinces of China, and found that, in comparison with the susceptible strain (MED-S), B. tabaci from most field populations were highly susceptible, except for the Haidian population (HD) which exhibited an approximately 40-fold increase in resistance. The HD population also displayed significant cross-resistance to sulfoxaflor (14.5-fold) but little cross-resistance to cyantraniliprole, flonicamid, imidacloprid, pymetrozine, and thiamethoxam. Afidopyropen resistance of the HD population was determined to be incomplete dominant and autosomal, and synergism assays demonstrated that P450 monooxygenases could contribute to the field-evolved afidopyropen resistance observed in the HD population. These results will further our understanding of the molecular underpinnings of insecticide resistance in B. tabaci and can inform the development of field-based pest control tactics to slow the development of afidopyropen resistance and to control whiteflies more sustainably. Full article

Bemisia tabaci is a devastating agricultural insect pest worldwide, and B. tabaci MED (formerly biotype ‘Q’) threatens the production of horticultural and economic crops in China as a growing number of cases of insecticide resistance have issued, highlighting the requirement for alternative methods and measures of pest management. In the present work, the toxicities of eight popular chemical agents, including the novel pyropene insecticide afidopyropen, on adults of B. tabaci MED were determined, and then physiological and biochemical responses to sublethal concentrations were confirmed. Among all tested chemical agents, afidopyropen exhibited the highest toxicity to adult whiteflies (LC₅₀: 7.38 mg/L). The sublethal effects of afidopyropen were studied at two sublethal concentrations, LC₁₀ (0.53 mg/L) and LC₂₅ (1.84 mg/L), and LC₂₅ treatment extended the duration of growth stages and reduced viabilities in the stages of nymphal, pseudopupae, and adults. The egg-laying days and eggs laid per female were also decreased significantly, as was hatchability in the LC₂₅ treatment. Metabolic enzyme assays suggested that the sublethal effects of LC₂₅ treatment could be ascribable to enhanced detoxification mediated by glutathione S-transferase. In summary, our findings indicate that afidopyropen can be used as a chemical agent for the management of B. tabaci MED whiteflies. Full article

Biorational insecticides (for instance, avermectins, spinosins, azadirachtin, and afidopyropen) of natural origin are increasingly being used in agriculture. The review considers the chemical ecology approach for the search for new compounds with insecticidal properties (entomotoxic, antifeedant, and hormonal) produced by fungi of various ecological groups (entomopathogens, soil saprotrophs, endophytes, phytopathogens, and mushrooms). The literature survey revealed that insecticidal metabolites of entomopathogenic fungi have not been sufficiently studied, and most of the well-characterized compounds show moderate insecticidal activity. The greatest number of substances with insecticidal properties was found to be produced by soil fungi, mainly from the genera Aspergillus and Penicillium. Metabolites with insecticidal and antifeedant properties were also found in endophytic and phytopathogenic fungi. It was noted that insect pests of stored products are mostly low sensitive to mycotoxins. Mushrooms were found to be promising producers of antifeedant compounds as well as insecticidal proteins. The expansion of the number of substances with insecticidal properties detected in prospective fungal species is possible by mining fungal genomes for secondary metabolite gene clusters and secreted proteins with their subsequent activation by various methods. The efficacy of these studies can be increased with high-throughput techniques of extraction of fungal metabolites and their analysis by various methods of chromatography and mass spectrometry. Full article

Aphids are important pests of pecans. Traditionally, insecticides have been the primary method of management. However, over-reliance and non-judicious use has led to resistance and damage to natural enemy populations. Therefore, frequent assessment of insecticides is necessary in order to monitor resistance development and non-target impacts. Aphicides, flonicamid, sulfoxaflor, and afidopyropen were assessed for their effects on pecan aphids and parasitoid, Aphelinus perpallidus, in a mature pecan orchard in 2019 and 2020. Post-application assessments were performed 7, 14, and 21 days post-application. Leaf samples from non-treated trees had greater aphid numbers than treated trees 7 days post-application with differences diminishing throughout the other two treatment periods in 2019. In 2020, aphid numbers were lower but leaf samples from non-treated trees had more aphids than treated trees 7 days post-application in the lower canopy. These differences again diminished 14 and 21 days post-application. There was no difference among treatments in number of parasitoid adults or mummies. These findings indicate that pecan growers have multiple potential options available for aphid management that do not negatively impact the primary pecan aphid parasitoid. Implications of the results on pecan aphid management are discussed. Full article