Int. J. Agricult. Stat. Sci. Vol. 16, Supplement 1, pp. 1221-1224, 2020 www.connectjournals.com/ijass DocID: https://connectjournals.com/03899.2020.16.1221 ISSN : 0973-1903, e-ISSN : 0976-3392 ORIGINAL ARTICLE INSECTICIDAL POTENTIAL OF TiO2 NANO-PARTICLES AGAINST EURYGASTER TESTUDINARIA (GEOFFROY) UNDER LABORATORY CONDITIONS Ahmed Saeed Mohmed Department of Field Crops, College of Agriculture, Al-Qasim Green University, Iraq. E-mail: [email protected] Abstract: Nano-particles have become one of the most promising new approaches for pest control in recent years. In this study, laboratory trails were carried out to investigate the insecticidal potential of TiO2 nano-particles against nymphs and adults of Eurygaster testudinaria. TiO2 nano-particles were found to be highly effective against E. testudinaria. The results also showed that mortality rates of adults and nymphs were significantly increased with days after application and concentration of TiO2 nano-particles with 41.15% and 43.08% mortality, respectively at 100 mg/L after 7 days from treatment. Results indicated that TiO2 nano-particles can be used as a valuable way in pest management of E. integriceps to reduce the indiscriminate use of conventional pesticides. Key words: Eurygaster testudinaria, Mortality, Nano-particles. Cite this article Ahmed Saeed Mohmed (2020). Insecticidal potential of TiO2 nano-particles against Eurygaster testudinaria (Geoffroy) under laboratory conditions. International Journal of Agricultural and Statistical Sciences. DocID: https:// connectjournals.com/03899.2020.16.1221 1. Introduction These reasons have led to a growing interest in the novel and effective alternatives that are eco-friendly In recent years, the sunn pest (Eurygaster [Mohmed (2019)]. One of these alternative methods is integriceps, Hemiptera : Scutelleridae) has spread nano-particle insecticides. Several nano-particles types widely in central and southern Iraq, causing losses of have been shown highly effective against insect pests wheat and barley crop yield up to 100%, nymphs and as a result of their small size, high surface to volume adults feeding and sucking on plant juices at the place ratio, minimal toxicity and side effects on the where the leaves contact the stem which leads to the environment [Dimetry and Hussein (2016)]. One of the death of the leaves, and therefore to low vegetative most used nano-particles is titanium dioxide nano- growth stage. In addition, feed on different stages of particles which have been shown to be effective in developing grains by sucking the milky nutrient and controlling some insects [Shaker et al. (2017), injecting enzyme complex such as amylases and Chakravarthy et al. (2012)]. proteases conducive to break down of gluten proteins resulting in the production of low quality of flour and Although, little information is available on the bread [Mehrabadi et al. (2010)]. efficacy of nano-particles against E. integriceps, our study is aimed to evaluate the entomotoxicity of TiO2 Currently, chemical insecticides are the most nano-particles against E. integriceps. common control method of E. integriceps, but their extensive use results in environmental pollution, 2. Materials and Methods insecticide resistance and negative side effects on The study was conducted under laboratory human health [Damalas and Eleftherohorinos (2011)]. conditions at Department of Field Crops, College of Received January 02, 2020 Revised June 24, 2020 Accepted July 28, 2020 1222 Ahmed Saeed Mohmed Agriculture, Al Qasim Green University, Babylon, Iraq. 2.5 Bioassay Test 2.1 Nano-particles Ten adults or nymphs of E. integriceps were placed The TiO2 nano-particles were obtained from Dr. in each Petri dish (90 × 15 mm), ignoring the sex. The Ayad F. Alkaim, Department of Chemistry, College of plates contained a sterile filter paper at the bottom and Science for Women, University of Babylon, Iraq. The ventilation holes in the covers. Two ml of each nano- particle size of (< 100 nm) and was prepared according particle concentration were applied to each Petri plate to the method described by [Ahmed et al .(2016 ) ]. using a spray hand. Petri plates in control treatment were sprayed with sterile distilled water only. The 2.2 Scanning Electron Microscope (SEM) experiment is carried out with three replicates for each The examination, size and photographing of the concentration and insect growth stage. Treated insects TiO2 nano-particles were measured using a Scanning were transferred to the incubator at 27±1°C, 60±10% Electron Microscope at Faculty of Science, University r.h. and 16L:8D photoperiod and mortality were of Kufa, Najaf, Iraq. recorded after 1,3,5,7 days post-treatment. 2.3 Preparation of nano-particle suspensions 2.6 Statistical analysis The nano-particles were suspended directly in The obtained data were analyzed using GenStat distilled water and dispersed by ultrasonic vibration package 3 (3 rh edition) with a Randomized complete (100W, 40 kHz) for 30 minutes. Small magnetic bars block design with three factors. The percentage effects were placed in the suspension for stirring to avoid of the nano-particle suspensions were calculated and aggregation of the particles. Different concentrations corrected using Abbott’s formula [Abbot (1925)]. of TiO2 (0, 50, 75, 100 mg/L) were prepared for later Angular transformation was used for Mortality experiences. statistical analysis. The treatment means were 2.4 Insect collection and rearing compared by least significant difference (L.S.D) at 5% Nymphs and adults of E. integriceps were level of significance. collected from wheat farms then transferred to the 3. Results and Discussion laboratory. Insects were placed in plastic boxes (25 × 3.1 Structural study of TiO2 nano-particles 35 × 18 cm) and covered with a muslin cloth, secured using a rubber band and were kept at 27±1°C, 60±10% The morphology, structure, and size of the samples r.h. and 16L:8D photoperiod as described by Allahyari were investigated using Scanning Electron Microscopy et al. (2010). (SEM). Fig. 1 indicated that the original morphology of the TiO2 nano-particles was approximately oval. It can Fig. 1: SEM micrograph of TiO2 NPs in different zoom Insecticidal potential of TiO2 nanoparticles against E. testudinaria 1223 be seen that the sample consists entirely of nano- concentration (2400 ppm). The effect may be due to particles with an average size (< 100 nm). the absorbance of TiO2 NPs into the insect’s wall 3.2 Effect of TiO2 nano-particles suspensions on cuticular lipids resulting in destroy to the barrier wax mortality of E. integriceps layer (made up of various fatty acids and lipids that serve as effective protection to water loss) and lead to The mortality rates of different concentrations of death by desiccation [Rahman et al. (2009)]. Also, TiO2 NPs against E. integriceps presented in Table 1 because reduced membrane permeability and disruption were significant at P 0.05 level. The mortality rates Table 1: Mean mortality of the effect of TiO2 NPs on E. integriceps for different days. Mortality (%) Stage Concent. (mg/L) Day Mean Mortality 1 3 5 7 0 0.00 0.00 0.00 0.00 0.00 50 0.00 18.44 23.85 28.78 17.77 Adult 75 0.00 23.85 30.99 35.22 22.52 100 0.00 28.78 35.22 41.15 26.29 0 0.00 0.00 0.00 0.00 0.00 50 0.00 21.15 28.78 33.21 20.78 Nymph 75 0.00 28.78 35.22 39.18 25.79 100 0.00 33.21 39.23 43.08 28.88 Mean Mortality 0.00 19.28 24.16 27.58 L.S.D (P 0.05) Insect Stages 1.1, Concentration 1.5, Time period 1.5, Interference 4.4 caused by all concentrations were significantly higher of proton motive force, cell function loss and cell death than the control treatment. The mortality of adult and occur [Jiang et al. (2015)]. nymphs of E. intercepts treated with all TiO2 NPs 4. Conclusion concentrations started after 3 days, where mortality of The results examined effectively TiO2 NPs against 28.78% and 33.21% was obtained with TiO2 NPs at adult and nymphs of E. intercepts, where mortality 100 mg/L for adult and nymphs, respectively, compared rates caused by all concentrations were significantly with 0.00% and 0.00% in control treatment. The higher than control treatment. In addition, the rate of mortality observed increased gradually with each passing mortality of adults and nymphs of E. integriceps were day to reach 41.15% and 43.08% for adults and nymphs increased with increasing the exposure time. on day 7 at 100 mg/L. This result is consistent with Accordingly, the use of TiO2 NPs as nanoinsecticide is other researcher’s reports such as Shaker et al. (2017), more acceptable because of effectively to control insect who indicated that TiO2 nano-particles affected the 2nd and they are safe for plants and causes less and 4th instar larvae of Spodoptera littoralis. Similar environmental pollution. results were obtained by [Al-Bartya and Hamzab (2015)], who indicated that an increase in the mortality Acknowledgement rate of the larval stage of Rhynchophorus ferrugineus The author thanks Dr. Ayad F. Alkaim to supply using TiO2 NPs synthesized from the aqueous extract nano-materials. Thanks are also to the staff of the of Moringa oleifera. Chakravarthy et al. (2012) center Scanning Electron Microscope at University of evaluated the effects of CdS, Ag and TiO2 nano- Kufa to photograph the sample. particles with 5 concentrations against 2nd instar larvae References of S. litura in the laboratory. They found that the Abbot, W.S. (1925). A methods of Computing the mortality of larval stage were 93.79, 73.79 and 56.89% Effectiveness of an insecticide. J. Econ. Entomol., 18, for CdS, TiO2 and Ag, respectively at the high 1224 Ahmed Saeed Mohmed 265-267.