Influence of Potassium Silicate on the Survival, Development and Reproduction of Aphis gossypii Glover (Hemiptera: Aphididae)

Document Type : Original Article

Authors

1 Applied Entomology and Zoology Department, Faculty of Agriculture, Alexandria University, El-Shatby, P.O. Box 21545, Alexandria, Egypt

2 Cotton Pesticides Evaluation Department, Plant Protection Research Institute, Agricultural Research Center, El-Sabhia, P.O. Box 21616, Alexandria, Egypt

Abstract

Induced plant resistance is an important component of pest control. Therefore, effects of potassium silicate (K2SiO3) on the survival, development and reproduction of Aphis gossypii Gloverat various life stages were tested under laboratory conditions. Efficacy of foliar spraying with K2SiO3 compared to lambda-cyhalothrin (LCH) against the field strain of A. gossypii third nymphal instar under greenhouse conditions as well as its impacts on the activity of antioxidant enzymes were also evaluated. In laboratory studies, K2SiO3 (LC50 = 58.21 mg L-1) was less toxic than LCH (LC50 = 44.32 mg L-1) against A. gossypii first nymphal instar after 48 h treatment. There was no significant difference in the developmental duration of total nymphal stages among the three treatment concentrations (LC10, LC25 andLC50) and the control. Treatments with K2SiO3 significantly reduced the longevity and fecundity of adult aphids. Reduction percentages of A. gossypii field strain after feeding on cotton leaves sprayed with K2SiO3 were 47.1 and 55.0 % at 100 and 200 mg L-1, respectively,compared to 67.9 and 77.5% in LCH. The higher levels of catalase and polyphenol oxidase enzymes activities was observed at 24 h with percentages 68.16 and 32.74%, respectively, compared to the control, then declined and reached to minimum value at 96 h. However, peroxidase enzyme activity was increased with percentage 59.72 % at 12 h and decreased to reach minimum value at 48 h. This study could introduce promising plant resistance inductors for use in integrated pest management of A. gossypii on cotton plant.
 

Keywords

Main Subjects