TiO2 nanoparticles as an effective nanopesticide for cotton leaf worm

Abstract

• The Egyptian cotton leaf worm, Spodoptera littoralis (Boisd.) (Noctuidae: Lepidoptera) is an economically important pest with a wide range of host plants. It attacks certain vegetable and field crops such as cotton, tomatoes, cabbage and squash in Egypt, for causing severe injuries to the plants in all phonological crop stages, In addition to this species has acquired resistance to many insecticides. The overall objective of this investigations was to look for new control strategy through evaluate the effects of application of TiO₂ nanoparticles on the survival and biology of this insect. The experiment were carried out under laboratory conditions, the experiment was achieved with two treatments, consisting of TiO₂ nanoparticles application, and a negative control (distilled water) against the second and fourth instar larvae of S.littoralis. The LC₅₀ value of the 2nd instar larvae treated with TiO₂ nanoparticles found to be 62.5 ppm, with slope 1.58 and LC₅₀ value was 125 ppm with slope 2 for the 4th instar., the treatment was applied at six concentrations, 1000, 500, 250, 125, 62.5 and 31.25ppm.The 2nd and 4th instar larvae were fed for 48h on treated leaves with TiO₂ nanoparticles, the mortality was detected after 15 days post application. The following evaluations were performed: a) Mortality %, b) Biological parameters of the insect were studied at the LC₅₀ values. Results of the treatments of TiO₂ nanoparticles in larval test indicated higher toxic action at all concentrations used for the 2nd instar parallel with concentrations than the 4th one.