The productivity of vegetable crops is constrained by insect pests. The search for alternative insect pest control is becoming increasingly important and is including the use of plant-derived pesticides. Plant-derived pesticides are reported as effective in controlling various insect pests through natural mechanisms, with biodegradable organic materials, diverse bioactivity, and low toxicity to non-target organisms. An antifeedant approach for insect control in crop management has been comprehensively studied by many researchers, though it has only been restricted to plant-based compounds and to the laboratory level at least. Nano-delivery formulations of biopesticides offer a wide variety of benefits, including increased effectiveness and efficiency (well-dispersion, wettability, and target delivery) with the improved properties of the antifeedant. This review paper evaluates the role of the nano-delivery system in antifeedant obtained from various plant extracts. The evaluation includes the research progress of antifeedant-based nano-delivery systems and the bioactivity performances of different types of nano-carrier formulations against various insect pests. An antifeedant nano-delivery system can increase their bioactivities, such as increasing sublethal bioactivity or reducing toxicity levels in both crude extracts/essential oils (EOs) and pure compounds. However, the plant-based antifeedant requires nanotechnological development to improve the nano-delivery systems regarding properties related to the bioactive functionality and the target site of insect pests. It is highlighted that the formulation of plant extracts creates a forthcoming insight for a field-scale application of this nano-delivery antifeedant due to the possible economic production process.

Synthetic insecticides frequently cause pest resistance and destroy non-target organisms. Thus, virus formulation is an issue that deserves considerable attention in developing virus-based insecticides. The hindrance of using nucleopolyhedrovirus alone as a virus-based insecticide is due to slow lethal time, though its mortality remains high (100%). This paper reports the formulation of zeolite nanoparticles as a delivery system to accelerate lethal time in controlling Spodoptera litura (Fabr.). Zeolite nanoparticles were prepared using the beads-milling method. The statistical analysis was carried out by a description exploration method with six replications. The occlusion bodies’ concentration in the virus formulation was 4 × 10⁷ OBs in 1 mL medium. Zeolite nanoparticles formulation sped up the lethal time significantly (7.67 days) compared to micro-size zeolite (12.70 days) and only nucleopolyhedrovirus (8.12 days) and received acceptable mortality (86.4%). The zeolite nanoparticles delivery system provides an alternative formulation for nucleopolyhedrovirus with a significantly improved speed of killing the virus while maintaining suitable efficacy of the virus preparation in terms of the prevalence of mortality.

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 (HaNPV(1)) 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 x 10(7) of HaNPV(1). 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 HaNPV(1) 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 HaNPV(1) 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.

The preparation of emulsification by low-energy phase inversion is an appropriate method for providing a nanosuspension of Lantana camara Ethyl Acetate Fraction (EAF) dispersed in water. In the formulation, the challenge faced is preventing the re-agglomeration of nanosuspension and stabilizing the formula over the storage period. This study reports the preparation of the L. camara EAF in water media using a low-energy phase inverse emulsion method with the modification of ultrasonic applications. The low-energy ultrasonic application effectively breaks the larger clusters of L. camara EAF suspension into a nanosuspension, allowing for a 77% increase in the distribution of primary size particles (8.3 ± 1.3 nm) and receiving a higher fraction of nano sized particles dispersed in the water solvent. It showed by the increase of zeta potential and the reduction of index polydispersity (Z = –8.5 mV, PI = 0.665) after sonicated. Optimal ultrasonication of the prepared L. camara EAF nanosuspension is achieved with a 50% amplitude vibration maintained for 60 minutes, which can effectively control the nano-size particle dispersion as well as improve the stability of the suspension. The L. camara EAF nanosuspension also maintained stability over the 60 days of storage with re-stirring and re-ultrasonic agitation. The effective ultrasonic application was critical in controlling the size distribution and stability of the prepared L. camara EAF nanosuspension through low-energy emulsification.