Development of an artificial diet for the western corn rootworm

Abstract

The Western Corn Rootworm, Diabrotica virgifera (WCR; Coleoptera: Chrysomelidae), is a serious pest of maize, causing approximately one billion dollars a year in losses and control costs. The insect has become resistant to several chemical controls and growers have asked for a control solution based on genetically-enhanced resistant varieties. Key to the production of genetically-enhanced germ plasm is the ability to use artificial diets for bioassays to identify proteins with activity against the target insect. However, artificial diets currently used for WCR bioassay do not support good WCR larval development because they were developed and optimized for the Southern Corn Rootworm (SCR). The present study was conducted to understand the nutritional physiology of WCR by altering the dietary constituents of a SCR diet and measuring the subsequent effects on WCR growth. Alteration of most dietary constituents had surprisingly little effect on WCR larval growth. The most significant factors affecting WCR growth on artificial diet were removal of formalin, addition of plant adjuvant, and adjustment of dietary pH to 9.0. These dietary changes resulted in larval WCR growth rates that were nearly double those in standard SCR rootworm diets. In some cases, WCR larvae fed on the improved diet obtained larval masses approaching those of larvae fed on maize roots.

Baseline Susceptibility of Western Corn Rootworm (Coleoptera: Crysomelidae) to Cry3Bb1 <I>Bacillus thuringiensis</I> Toxin

“…MgSO 4 ßotation was repeated as necessary. The eggs were then disinfected to reduce microbial contamination by using techniques adapted from Pleau et al (2002). Brießy, the eggs were cleaned Þrst with Lysol brand disinfectant followed by 10% formalin for 2 min each and triple rinsed with sterile water.…”

“…Bioassays involved surface treatment of single wells of artiÞcial diet dispensed into 96-well microtiter plates. The artiÞcial diet used in all bioassays was prepared as described by Pleau et al (2002). Bioassays were performed in 96-well microtiter plates (Falcon 353910, BD Biosciences, Franklin Lakes, NJ).…”

Binary Toxins from Bacillus thuringiensis Active against the Western Corn Rootworm, Diabrotica virgifera virgifera LeConte

“…Two different quantitative bioassays were run with WCR larvae. For the first WCR bioassay protocol, 200 ml of the WCR diet was prepared in a manner similar to that described by Pleau et al (36). The following dilutions of the test samples were prepared by using water as a diluent: 300, 200, 133, 89, 59, 40, and 26 ppm of crystal protein.…”

Isolation and identification of mosquito larvicidal compound from Abutilon indicum (Linn.) Sweet

“…Earlier authors reported that the β-sitosterol was isolated from Croton cajucara (Maciel et al 2000); Sitophilus granarius (Johannes et al 2001) and leaves of Sebastiania adenophora (Rubalcava et al 2007) were tested against the larvae of Diabrotica virgifera (Pleau et al 2002); anticancer activities (Kim et al 2002;Wahab et al 1998) from Senecio lyratus showed antifungal and anti-bacterial activities (Kiprono et al 2000) and were studied for antiatherosclerotic effect (Wang et al 2006); and insecticidal activity (Zolotar et al 2002a) against the larvae of Leptinotarsa decemlineata (Zolotar et al 2002b) was studied against the larval parasitoid Lariophagus distinguendus (Johannes et al 2001). This is the first report of compound β-sitosterol being isolated from A. indicum and tested against the mosquito larvae.…”