The Institute of Plant Protection of the Chinese Academy of Agricultural Sciences has developed a sustained-release capsule for entomopathogenic nematodes.

Release Date:

2025-09-02

Recently, the Innovative Team for Pest Monitoring and Control of Economic Crops at the Institute of Plant Protection, Chinese Academy of Agricultural Sciences, published online in Entomologia Generalis a research paper titled “Enhancing heat tolerance and delivery efficiency of entomopathogenic nematodes with glycerol-calcium alginate gel beads.” The study developed a sustained-release capsule for entomopathogenic nematodes and demonstrated its advantages in heat resistance, mechanical properties, and prolonged insecticidal efficacy, providing both theoretical foundations and technical pathways for the efficient application of biocontrol agents in complex environmental conditions.

Subterranean pests, particularly grubs, are a major focus of research in pest management due to their cryptic habits and the substantial damage they inflict on agricultural production. Grubs exhibit long life cycles, wide dispersal ranges, and a subterranean lifestyle, all of which significantly complicate their monitoring and control. Among numerous biocontrol agents, entomopathogenic nematodes (EPNs) stand out for their unique advantages in managing underground pests, as they share similar ecological niches with grubs and possess the ability to actively target and infect them. Since Gotthold Steiner first described EPNs in 1923, more than 75 species have been identified, with new species continuing to be discovered; however, large-scale field applications still face numerous challenges. The key obstacles hindering the widespread adoption of EPNs include: (i) their strong dependence on high-humidity conditions, which limits flexible logistics during transport and storage; and (ii) their poor tolerance to stressors such as elevated temperatures, severely restricting the temporal and spatial windows for field application. Consequently, developing functional carriers that combine mechanical robustness with environmental adaptability has emerged as a critical technological pathway for overcoming these limitations, enabling efficient, stable field release and long-term pest control.

This study focused on the entomopathogenic nematode Heterorhabditis bacteriophora HL6, which exhibits significant lethal activity against larvae of the darkling beetle. Based on the crosslinking reaction between sodium alginate (SA) and calcium ions, a novel functional gel‑bead carrier was developed. By modulating the glycerol concentration, the survival rate and recovery capacity of the nematodes were markedly enhanced, while the carrier material’s stress resistance was also improved. Furthermore, by adjusting the porosity of the gel, the controlled‑release performance of the entomopathogenic nematodes was optimized, and the impact of nematode loading on release efficiency was systematically evaluated. The study also comprehensively characterized the carrier’s structural features, mechanical properties, thermal stability, and insecticidal efficacy. This research provides both theoretical foundations and technical support for the design and optimization of functional carriers for entomopathogenic nematodes, laying a solid groundwork for their efficient application in diverse agricultural settings and ecological environments.