The attractiveness of phagostimulant formulations of a nucleopolyhedrovirus-based insecticide depends on prior insect diet

Abstract

The multiply-enveloped nucleopolyhedrovirus (SeMNPV) of Spodoptera exigua (Hübner) is being employed on an increasing scale as the basis for bioinsecticidal products for control of this pest in greenhouse crops in Europe. The mortality of diet-reared S. exigua larvae was determined after feeding on lettuce leaf discs contaminated by mixtures of SeMNPV occlusion bodies and 1 of 13 substances reported to have phagostimulant properties. Of the substances tested, wheatgerm and soya Xour resulted in signiWcantly increased mortality compared to the virus alone. However, these preferences disappeared when larvae were reared on lettuce. We conclude that (1) the activity of potential phagostimulant substances depends on the prior feeding experience of S. exigua and, (2) laboratory tests using diet-reared insects require validation using plantreared larvae before being developed for Weld testing.

The addition of molasses to the Cryptophlebia leucotreta granulovirus formulation improves its efficacy against Thaumatotibia leucotreta Meyrick (Lepidoptera: Tortricidae), a pest of citrus in South Africa

“…This was irrespective of the brand or formulation (i.e., liquid or powder). The enhanced performance of insect viruses with the addition of phagostimulants under field conditions has been reported by Sood et al (2013) and Ballard et al (2000), amongst others (Burges and Jones 1998;Cisneros et al 2002;Lasa et al 2009;Knight et al 2015;Kour et al 2022;van Der Merwe et al 2023). Sood et al (2013) linked an increase in feeding activity with an increase in larval mortality in leaf-disc bioassays, with 2% boric acid and 2% crude sugar being the most effective.…”

Feeding Response of Subterranean Termites <I>Coptotermes curvignathus</I> and <I>Coptotermes gestroi</I> (Blattodea: Rhinotermitidae) to Baits Supplemented With Sugars, Amino Acids, and Cassava

“…The sugars were suggested by Waller and Curtis (2003) and Saran and Rust (2008) and amino acids by Chen and Henderson (1996), all of which positively improved consumption of the bait matrices by their test species of termites. Furthermore, MSG has been shown to increase feeding activities of insects such as the beet armyworm, Spodoptera exigua (Hü bner) (Lasa et al 2009), and codling moth, Cydia pomonella L. (Pszczolkowski et al 2002). The sugars, amino acids, and MSG were dissolved in distilled water to concentrations of 3, 6, 9, 12, and 15% (wt:vol).…”

Enhancing the Efficacy of Certain Spray-Dried Baculovirus (AgipMNPV) against Cutworm, Agrotis ipsilon Hufnagel (Lepidoptera: Noctuidae)

“…In addition to improving the speed of kill, efficacy, host range, and persistence applied research on the formulation of BV remains one of the most important routes to BV product improvement (Behle and Birthisel, 2014). Adjuvant may need to be incorporated to inhibit microbial contamination as well as protect the baculovirus from adverse environmental factors such as temperature, leaf surface exudates, sunlight, wind, and rain, thereby improving their persistence, helping to maintain their insecticidal activity, enhance storage stability and maximize application efficiency (Behle et al, 2011;Lasa et al, 2009). Additives that enhance the active ingredient such as flour, oil, and sugar often act as phagostimulants and have other enhancing properties such as facilitating adhesion of the virus to plants.…”