Search Results (10)

Insulin-like peptides (ILPs) are important peptide hormones in insects, particularly involved in regulating physiological processes such as growth, development, and reproduction. However, the specific roles of ILPs in the reproduction of natural enemy insects remain unknown. In this study, two ILP genes, CsILP1 and CsILP2, were cloned and their functions were analyzed in female Coccinella septempunctata L. (Coleoptera: Coccinellidae). The open reading frames (ORFs) of CsILP1 and CsILP2 were 384 bp and 357 bp, respectively. The expression of CsILP1 increased on the 6th day after eclosion, reaching its peak on the 12th day, while CsILP2 levels showed a significant increase on the 6th day and then stabilized. In different tissues, CsILP1 was highly expressed in ovaries, while CsILP2 predominated in elytra. Injection of dsRNA targeting CsILP1 and CsILP2 resulted in the down-regulation of insulin pathway genes. The relative expression of ovarian development-related genes Vasa, G2/M, and Vg was reduced by 82.50%, 89.55%. and 96.98% in dsCsILP1-treated females, and by 42.55%, 91.36%, and 55.63% in dsCsILP2-treated females. Furthermore, substantial decreases in 14-day fecundity were observed, with reductions of 89.99% for dsCsILP1 and 83.45% for dsCsILP2. These results confirm the regulatory functions of CsILP1 and CsILP2 in female C. septempunctata reproduction. Full article

Coccinella septempunctata (ladybird) is an extremely important natural predator that feeds on aphids. An assessment of the toxicity of pesticides on environmental organisms is an essential component of Integrated Pest Management (IPM) strategies. This study evaluated diamide insecticides’ toxicity at lethal and 30% lethal doses (LR₃₀) against C. septempunctata larvae. The pre-imaginal median lethal doses (LR₅₀) of chlorantraniliprole 10% SC, tetrachlorantraniliprole 10% SC, and broflanilide 10% SC were calculated to be 42.078, 289.516, and 0.0943 g active ingredient (a.i.)/ha, respectively. The mortality tests demonstrated that chlorantraniliprole and tetrachlorantraniliprole are comparatively less toxic to C. septempunctata than broflanilide, which were detected to be highly toxic to C. septempunctata. The mortality rates of the groups treated with the three diamide insecticides tended to stabilize after 96 h, extending to the pre-imaginal stage. Furthermore, when compared to broflanilide, which had a much higher potential risk, the hazard quotient (HQ) values indicated that chlorantraniliprole and tetrachlorantraniliprole have a lower risk potential for C. septempunctata in farmland and off farmland. The LR₃₀ dose induces abnormalities in the development phase 4th-instar larvae weight, pupal weight, and adult weight of treated C. septempunctata. The study emphasizes the importance of assessing the adverse effects of diamide insecticides on natural predator species that serve as biological control agents in agricultural IPM strategies. Full article

Cathepsin L protease, which belongs to the papain-like cysteine proteases family, is an important player in many physiological and pathological processes. However, little was known about the role of cathepsin L in ladybird beetles (Coccinella septempuctata Linnaeus) during diapause. Here, we analyzed the characteristics of cathepsin L (CsCatL) in the females of C. septempunctata and its role during the diapause of the ladybeetle. CsCatL was cloned and identified from beetle specimens by rapid amplification of cDNA-ends (RACE). The cDNA sequence of CsCatL was 971 bp in length, including an 843 bp open reading frame encoding a protein of 280 amino acids. It was identified as the cathepsin L group by phylogenetic analysis. Knockdown of CsCatL by RNA interference led to decreased expression levels of fatty acid synthase 2 (fas 2) genes and suppressed lipid accumulation. Furthermore, silencing the CsCatL gene distinctly reduced diapause-related features and the survival of female C. spetempunctata under diapause-inducing conditions. The results suggested that the CsCatL gene was involved in fatty acid biosynthesis and played a crucial role in the survival of adult C. septempunctata during the diapause preparation stage. Full article

Coccinella septempunctata is a nontarget beneficial arthropod and an important aphid predator in agricultural crops. In this study, the toxic effects of the neonicotinoid acetamiprid on C. septempunctata were investigated to determine its applicability and efficacy against the aphid predator. The results of the toxicity test showed that the second instar larvae of C. septempunctata were the most sensitive to acetamiprid. The LC₅₀ values of the 1st, 2nd, 3rd, and 4th instar larvae were 15.767, 9.412, 18.850, and 25.278 mg a.i. L⁻¹, respectively. Compared with that of the control, the predation ability of different larval instars was inhibited by sublethal concentrations of acetamiprid. The results of the predatory function test showed that sublethal concentrations of acetamiprid could reduce the consumption of aphids by fourth instar C. septempunctata larvae over a short duration and significantly inhibited the predatory ability of ladybird larvae. The results of the developmental test showed that sublethal concentration of acetamiprid shortened the growth duration of C. septempunctata larvae. Acetamiprid had considerable adverse effects on the different developmental stages of C. septempunctata. Together, our results provide information for implementation in biological and chemical control strategies for the integrated management of aphids. Full article

The aim of this study was to determine the effects of water extracts of tarragon (Artemisia dracunculus L.) on the feeding intensity, mortality, and weight gain of selected pests, i.e., adult pea leaf weevils (Sitona lineatus L.), nymphs, wingless females of black bean aphids (Aphis fabae Scop.), and L2 and L4 larvae of Colorado potato beetle (Leptinotarsa decemlineata Say). In addition, the effect of the tarragon extracts on the voracity of the non-target organism Coccinella septempunctata L. L3 larvae was examined. To reduce S. lineatus feeding, at least 10% dry matter (DM) extract and 20% fresh matter (FM) should be used. Tarragon water extract has strong aphicidal potential against A. fabae, with 84% mortality of nymphs at 30% FM and 78% mortality of wingless females at 10% DM after 108 h of exposure. Aphid nymphs turned out to be more sensitive to the extracts prepared from fresh tarragon than from its dry matter. They were also more sensitive than wingless females. The body weight gain of L2 and L4 larvae of Colorado potato beetle was significantly reduced through the application of 10% and 5% extracts prepared from dry matters, respectively, while extracts prepared from fresh matter turned out to be ineffective. L2 larvae were more susceptible to extracts than L4 larvae, which suggests that they should be used as early as possible in the pest season. No negative influence of the extracts used on the voraciousness of C. septempunctata L3 larvae was found. Full article

Aphids are the dominant pests in the complex of harmful fauna of stone fruits in Ukraine. In plum orchards mealy plum aphid Hyalopterus pruni Geoffr. (Hemiptera: Aphidinae) causes serious economic damage. Insect predators have an important role in the regulation of agricultural pests. Our goal was to determine the role of predation in the dynamics of the mealy-plum-aphid population. Investigations were carried out during the period of mass development of the mealy plum aphid in the experimental plum-orchard garden of the Institute of Horticulture of the National Academy of Agrarian Sciences of Ukraine. For this purpose, model trees were selected and isolators were installed on four branches of each tree with aphid-infested leaves. Different species of entomophagous predators were placed in the isolators and assessments were performed on a daily basis. According to our observations, Adalia bipunctata L., A. decempunctata L., Syrphus ribesii L., S. balteatus Deg, Chrysopa perla L., and Ch. carnea Steph. dominated among aphidophagous predators. Coccinella septempunctata L., Calvia quatuordecimguttata L., and Propylaea quatuordecimpunctata L. were less common. Syrphus and Chrysopa larvae had the highest predation activity. The influence of weather conditions on the efficiency of aphidophagous predators was analyzed. Optimal conditions for A. bipunctata, A. decempunctata, S. ribesii, S. balteatus, Ch. perla, and Ch. carnea during June–July were as follows: mean daily temperature, 17–20 °C, precipitation 0.1–1.5 mm, and relative air humidity 57–67%. The threshold ratios of dominant aphidophagous predators were determined. The high predation activity of Syrphus and Chrysopa larvae and coccinellids indicated that the ratio of entomophages to aphids must be taken into account when making decisions about control measures Full article

The sensitivity to thiacloprid and lambda-cyhalothrin ingested from prey organisms was studied in Coccinella septempunctata and Harmonia axyridis, since the effect of ingestion exposure to these insecticides is unknown in these species. All developmental stages of the ladybirds were fed on Acyrthosiphon pisum treated with half or full field rate of the insecticides. Almost all instars were killed within 3 h of the start of ingestion of lambda-cyhalotrin-treated prey. The action of thiacloprid was more extended in time in both coccinellids and more variable between their instars. Reducing the field rate of lambda-cyhalothrin seems to have no practical value for the survival of either of the coccinellid species. Contrastingly, using half instead of the full field rate of thiacloprid may enhance the chances of survival in L1, L2, and L4 larvae of both species. Of all developmental stages tested, the survival dynamics of the adults of either species are closest to one another, whereas the apparent difference in the species response to the dose rate of thiacloprid was found in the L4 stage. Full article

The use of chemical insecticides has had several side-effects, such as environmental contamination, foodborne residues, and human health threats. The utilization of plant-derived essential oils as efficient bio-rational agents has been acknowledged in pest management strategies. In the present study, the fumigant toxicity of essential oil isolated from Satureja intermedia was assessed against cosmopolitan stored-product insect pests: Trogoderma granarium Everts (khapra beetle), Rhyzopertha dominica (Fabricius) (lesser grain borer), Tribolium castaneum (Herbst) (red flour beetle), and Oryzaephilus surinamensis (L.) (saw-toothed grain beetle). The essential oil had significant fumigant toxicity against tested insects, which positively depended on essential oil concentrations and the exposure times. Comparative contact toxicity of S. intermedia essential oil was measured against Aphis nerii Boyer de Fonscolombe (oleander aphid) and its predator Coccinella septempunctata L. (seven-spot ladybird). Adult females of A. nerii were more susceptible to the contact toxicity than the C. septempunctata adults. The dominant compounds in the essential oil of S. intermedia were thymol (48.1%), carvacrol (11.8%), p-cymene (8.1%), and γ-terpinene (8.1%). The high fumigant toxicity against four major stored-product insect pests, the significant aphidicidal effect on A. nerii, and relative safety to the general predator C. septempunctata make terpene-rich S. intermedia essential oil a potential candidate for use as a plant-based alternative to the detrimental synthetic insecticides. Full article

Aphis gossypii Glover is a major pest of cotton and can severely affect cotton yield and lint quality. In this study, the efficacy of sulfoxaflor applied via drip irrigation and foliar spray on controlling cotton aphids was evaluated in 2016 and 2017 in Xinjiang, China. The distribution of sulfoxaflor in cotton roots, stems, leaves, and aphids, as well as its effects on two natural enemies of aphids, were also investigated. Results showed that sulfoxaflor applied through drip irrigation mainly concentrated in leaves and provided effective control of cotton aphids for 40 days, compared to 20 days when applied through foliar spray. Furthermore, drip application resulted in much lower sulfoxaflor concentrations in aphids than foliar spray. As a result, ladybird beetle and lacewing populations were higher in drip applied plants than in foliar sprayed plants. Additionally, the cost of drip irrigation was lower than foliar spray as cotton plants are commonly irrigated via drip irrigation in Xinjiang. Our results showed that application of sulfoxaflor through drip irrigation is an effective way of controlling cotton aphids in Xinjiang due to a prolonged control period, safety to two natural enemies, and lower cost of application. Full article

(1) Intraguild predation (IGP) can occur among aphidophagous predators thus reducing their effectiveness in controlling crop pests. Among ladybirds, Coccinella septempunctata L. and Hippodamia variegata Goeze are the most effective predators upon Aphis gossypii Glov., which is an economically important pest of melon. Understanding their likelihood to engage in reciprocal predation is a key point for conservation of biological control. Here, we aim to investigate, under laboratory conditions, the level of IGP between the two above mentioned aphidophagous species. (2) Fourth-instars of the two species were isolated in petri dishes with combinations of different stages of the heterospecific ladybird and different densities of A. gossypii. The occurrence of IGP events was recorded after six hours. (3) C. septempunctata predated H. variegata at a higher rate than vice versa (70% vs. 43% overall). Higher density of the aphid or older juvenile stage of the IG-prey (22% of fourth instars vs. 74% of eggs and second instars) reduces the likelihood of predation. (4) To our knowledge, IGP between C. septempunctata and H. variegata was investigated for the first time. Results represent a baseline, necessary to predict the likelihood of IGP occurrence in the field. Full article