Conventional agrochemicals towards nano-biopesticides: an overview on recent advances

Pesticides are classified into several groups based on their structure, including fungicides, insecticides, herbicides, bactericides, and rodenticides. Pesticides are toxic to both humans and pests. For pest control, a very small amount of pesticides reach their target pests. Therefore, nearly all pesticides move through the environment and exert adverse effects on beneficial biota and public health. These chemicals pollute the water, soil, and atmosphere of the ecosystem. Agricultural workers in greenhouses and open fields, exterminators of house pests, and workers in the pesticide industry are occupationally exposed to pesticides. Pesticide exposure in the general population primarily happens through the consumption of food and water contaminated with pesticide residues; however, substantial exposure can also occur outside or inside the house. Currently, intelligent, responsive, biodegradable, and biocompatible materials have attracted considerable interest for the formulation of green, safe, and efficient pesticides. It was indicated that utilizing nanotechnology to design and prepare targeted pesticides with an environmentally responsive controlled release via chemical modifications and compounds offers great potential for creating new formulations. Furthermore, biopesticides include microbial pesticides, which are naturally happening biochemical pesticides. In addition, pesticidal substances generated by plants with added genetic materials, i.e., plant-incorporated protectants (PIPs), have emerged. Based on the foregoing evidence, various types of pesticides are summarized in this review for the first time. Here, new pesticides including nano-pesticides and biopesticides are discussed while focusing on the most recent findings on targeted and safe nano-formulated biopesticides and nano-pesticides. Graphical Abstract

Overview of the testing and assessment of effects of microbial pesticides on bees: strengths, challenges and perspectives

Currently, there is a growing interest in developing biopesticides and increasing their share in the plant protection market as sustainable tools in integrated pest management (IPM). Therefore, it is important that regulatory requirements are consistent and thorough in consideration of biopesticides’ unique properties. While microbial pesticides generally have a lower risk profile, they present special challenges in non-target organism testing and risk assessment since, in contrast to chemical pesticides, their modes of action include infectivity and pathogenicity rather than toxicity alone. For this reason, non-target organism testing guidelines designed for conventional chemical pesticides are not necessarily directly applicable to microbial pesticides. Many stakeholders have recognised the need for improvements in the guidance available for testing microbial pesticides with honey bees, particularly given the increasing interest in development and registration of microbial pesticides and concerns over risks to pollinators. This paper provides an overview of the challenges with testing and assessment of the effects of microbial pesticides on honey bees (Apis mellifera), which have served as a surrogate for both Apis and non-Apis bees, and provides a foundation toward developing improved testing methods.

Identification of diverse viruses associated with grasshoppers unveils phylogenetic congruence between hosts and viruses

Locusts and grasshoppers are one of the most dangerous agricultural pests. Environmentally benign microbial pesticides are increasingly desirable for controlling locust outbreaks in fragile ecosystems. Here we use metagenomic sequencing to profile the rich viral communities in 34 grasshopper species and report 322 viruses, including 202 novel species. Most of the identified viruses are related to other insect viruses and some are targeted by antiviral RNAi pathway, indicating they infect grasshoppers. Some plant/fungi/vertebrate associated viruses are also abundant in our samples. Our analysis of relationships between host and virus phylogenies suggests that the composition of viromes is closely allied with host evolution, and there is significant phylogenetic relatedness between grasshoppers and viruses from Lispiviridae, Partitiviridae, Orthomyxoviridae, Virgaviridae and Flaviviridae. Overall, this study is a thorough exploration of viruses in grasshoppers and provide an essential evolutionary and ecological context for host-virus interaction in Acridoidea.

Microbial Pesticides for Insect Pest Management: Success and Risk Analysis

Biotic stress is a major cause for pre and postharvest losses in agriculture. Food crops of the world are damaged by more than of 10,000 species of insects 30,000 species of weeds, 1,00, 000 types of diseases (due to fungi, viruses, bacteria and various microbes) and a 1,000 species of nematodes. Modern day management practices for the above specified stress factors largely depends on the utilization of synthetic pesticides. Pesticide misuse in numerous sectors of agriculture frequently has often linked to health issues and environmental pollution around the world. Thus, there is a growing interest in replacing or possibly supplementing the prevailing control strategies with new and safer techniques. One of the promising management tools in this new state of affairs for crop protection is microbial pesticides. At present, only 3% of plant protectants used globally are covered by bio pesticides, but their growth rate indicates an increasing trend in the past two decades. The discovery of insecticidal property of Bacillus thuringiensis (Bt) indicated a more extensive part of organism based natural control. Microbial pesticides comprise of a microorganisms (bacterium, fungus, virus or protozoan) or toxins produced by them as the active ingredient. The most commonly used microbial pesticides are entomopathogenic fungi (Metarhizium, Beauveria and Verticillium), entomopathogenic bacteria (Bt), entomopathogenic nematode (Steinernema and Heterorhabditis) and baculoviruses (NPV and GV) which able to cause disease in insects. Microbial insecticides are promising alternative to ecologically disruptive pest control measures as they are no longer harmful to the environment and non target organisms. If deployed appropriately, microbial insecticides have capability to bring sustainability to global agriculture for food and food safety.