The Effect of Nanozeolite Concentration in a Delivery System of HaNPV1 to the Lethal Time against Crocidolomia pavonana

Abstract

The constraints on the effectiveness of nuclear polyhedrosis virus (NPV) as biocontrol are usually due to environmental factors such as temperature and ultraviolet (UV) exposure. Zeolite has been commonly used as a carrier or delivery system for nuclear polyhedrosis viruses. In this study, zeolite powder was reduced into nanosized particles by beads milling method and was investigated for the effect of its concentration in the delivery system of Helicoverpa armigera nuclear polyhedrosis virus (HaNPV1) on the lethal time against the larvae Crocidolomia pavonana. The formulation used three concentrations of nanozeolite suspension, 0.5, 1, 1.5, and 2 wt.% applied for each 4 × 107 of HaNPV1. A randomized block design (RBD) method was applied with 3 replications. The results showed that the scanning electron microscope (SEM) from nanozeolite was seen coating the entire surface of the HaNPV1 polyhedra and an increase of zeolite concentration caused acceleration of the lethal time of C. pavonana instar III. Thus, the fastest lethal time was 1.2 days receiving a concentration of 2 wt.%, which was significantly higher compared to without delivery (2.9 days). The increase of the zeolite concentration up to 2 wt.% in the delivery system for HaNPV1 improved their performance on lethal time and mortality against C. pavonana. It was concluded that nanozeolite as a delivery system enhanced and created a synergy in infecting C. pavonana.

Preparation and Evaluation of Zeolite Nanoparticles as a Delivery System for Helicoverpa armigera Nucleopolyhedrovirus (HaNPV) against the Spodoptera litura (Fabricius, 1775) Larvae

“…SEM images observed the subculture polyhedral's spherical and porous structure shape with magnification of 8500 (Figure 1b). The modification of the structure of HaNPV polyhedral in an alternate host was reported in our previous study [24]. A distinguishing feature of baculoviral is the presence of OBs, which are critical for the transmission of the virus in host insects and the survival of the virus outside the host [25].…”

“…where N is the number of polyhedral counted, V is the area counted (Neubauer counting chamber), and P is the dilution factor. The average lethal time was calculated using the formula in Equation ( 1) for 14 days of observation, according to Prasetio et al [24] as follows.…”

“…The HaNPV 1 + ZNPs biocontrol agent provided faster lethal time and possessed high mortality compared to only HaNPV 1 or ZNPs. The ZNPs have a strong affinity to target such proteins and initiate the abrading to membrane cells, causing the virus to easily enter the cell [12,24]. Therefore, ZNPs with HaNPV 1 reduce the lethal time of larvae due to effectively damaging cell membranes and creating fast viral replication in midgut cells [35].…”