Nanotechnology-Based Bioactive Antifeedant for Plant Protection

Abstract

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.

Keywords: antifeedant; biopesticides; nano-delivery system; nanotechnology; pest resistance; plant protection.

Figure 1

The negative impact of synthetic insecticides and effort of developing nanoformula-based antifeedant as an alternative to prevent pest resistance.

Figure 2

The types of nano-delivery biopesticide formulations.

Figure 3

Dispersion of nanosuspensions in the water system by micelle formation (highlighted in blue-grey for water, yellow for oil/non-polar solvent, green for plant-extract suspension, and grey for surfactant/Tween 80): (a) water–oil (W/O) formation, (b) water–oil–water (W/O/W) formation adopted from McClements and Rao [107], and (c) oil–water (O/W) formation.

Figure 4

Illustration of the distribution of droplets containing nano-delivery system as a result of droplet size and surface wettability of leaf against droplets (a); the image comparison of nano-micelle droplet of low wettability (left) and high wettability (high) on the leaf surface (b); and the reduction in surface tension of the droplets containing nano-sized suspension on the leaf surface (<90°) (c).