Insecticidal activity of chitosans of different molecular weights and chitosan-metal complexes against cotton leafworm Spodoptera littoralis and oleander aphid Aphis nerii

Abstract

Badawy M.E.I., El-Aswad A.F. (2012): Insecticidal activity of chitosans of different molecular weights and chitosan-metal complexes against cotton leafworm Spodoptera littoralis and oleander aphid Aphis nerii. Plant Protect. Sci., 48: 131-141.As an alternative to synthetic pesticides, chitosan has received much attention as a biopolymer active against some agricultural pests. The, insecticidal activity of chitosans of four molecular weights (2.27 × 10 5 , 3.60 × 10 5 , 5.97 × 10 5 , and 9.47 × 10 5 g/mol) was investigated against two species of arthropod pests: oleander aphidAphis nerii and cotton leafworm Spodoptera littoralis. In addition, the most active chitosan of 2.27 × 10 5 g/mol was chemically modified with metals of Ag(I), Cu(II), Ni(II), and Hg(II) to give corresponding chitosan-metal complexes. Larval mortality, growth inhibition, and antifeedant activities for third instar larvae of S. littoralis were evaluated at 4 g (a.i.) chitosan/kg diet. Chitosan of 2.27 × 10 5 g/mol and its complexes with Ni and Hg were the most active compounds. The results against A. nerii indicated that chitosans of 3.60 × 10 5 and 5.97 × 10 5 g/mol showed high activity among the different molecular weights in leaf-dip bioassay after 24 h of treatment with 48 and 49% mortalities, respectively, at 1000 mg/l. All compounds had a systemic effect against A. nerii. Chitosans of 2.27 × 10 5 , 3.60 × 10 5 , and 5.97 × 10 5 g/mol showed the highest efficacy at all concentrations tested; however, chitosan-Cu was significantly the most active among the complexes.

A Review of the Applications of Chitin and Its Derivatives in Agriculture to Modify Plant-Microbial Interactions and Improve Crop Yields

“…Despite these positive results and the ubiquitous nature of insect pests, there are still only a limited number of studies on the effects of chitin derivatives on insect pests of plants. Of the reports published in peer-reviewed journals effective control with chitosan has been demonstrated for insect pests in the orders Hemiptera (including aphids) [46] and Lepidoptera (chiefly moth pests) [45,46]. However, there is a notable absence of information on the effects on pests in the orders Coleoptera (beetles), Diptera (true flies), and Hymenoptera (wasps, termites, ants and sawflies), which together represent thousands of economically important plant pests.…”

Pengendalian Aphis craccivora Koch. dengan kitosan dan pengaruhnya terhadap penularan Bean common mosaic virus strain Black eye cowpea (BCMV-BlC) pada kacang panjang

“…Kandungan logam yang terikat pada kitosan, seperti Ag, Cu, Hg, Ni dan Zn dilaporkan mampu meningkatkan aktivitas biologi kitosan (Wang et al 2005). Menurut Badawy & El-Aswad (2012), semakin tinggi berat molekul dan kandungan logam Cu yang terikat pada kitosan menunjukkan penghambatan makan terhadap kutudaun yang semakin tinggi.…”

“…Kitosan dilaporkan memiliki efek insektisida yang mematikan Aphis nerii pada tanaman oleander dan Spodoptera littoralis pada tanaman kapas di Mesir (Badawy & El-Aswad 2012) serta mampu mematikan Plutella xylostella dan Helicoverpa armigera (Zhang et al 2003). Kitosan memiliki efek penghambat makan, aktifitas insektisida (Zhang et al 2003), serta antixenosis dan antibiosis pada kentang transgenik yang disisipi kitinase (Saguez et al 2005).…”

“…Selain memiliki efek penghambat makan (anti-feedant), aplikasi kitosan yang berulang pada tanaman mampu menunjukkan aktifitas insektisida (Aphisidal) terhadap A. nerii (Badawy & El-Aswad 2012) dan beberapa kutudaun lainnya (Zhang et al 2003). Namun, dalam penelitian ini kitosan hanya sekali diaplikasikan/disemprot pada daun dan mortalitas kutudaun tidak diamati sehingga efek insektisida (Aphisidal) tidak diketahui.…”

Development and testing of a novel glycerol/chitosan based biocide-free hydraulic fluid

“…It is already used in many different application fields, e.g. in water treatment (Gamage and Shahidi, 2007), medicinal applications (Martino et al, 2005), and agriculture (Badawy and El-Aswad, 2012). In the novel hydraulic fluid introduced here, the chitosan derivative carboxymethyl chitosan (CMC) is applied because of its superior water solubility .…”