Skip to main content
ARS Home » Southeast Area » Byron, Georgia » Fruit and Tree Nut Research » Research » Publications at this Location » Publication #422424
Research Project: Novel Approaches for Managing Key Pests of Peach and Pecan

Location: Fruit and Tree Nut Research

Title: Storage capacity of entomopathogenic nematodes in Barricade® Gel and Potassium Polyacrylate Hydrogel

Author
item ZULU, SINETHEMBA - Agricultural Research Council Of South Africa
item RAMAKUWELA, TSHIMANGADZO - Agricultural Research Council Of South Africa
item BAIMEY, HUGUES - University Of Parakou
item LAING, MARK - University Of Kwazulu-Natal
item Shapiro Ilan, David
item COCHRANE, NICOLENE - Agricultural Research Council Of South Africa

Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/25/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: Entomopathogenic nematodes (also known as beneficial nematodes) are small round worms that are used as natural biopesticides. These nematodes kill insect pests but do not harm humans or the environment. Survival of beneficial nematodes can be reduced due to UV radiation or desiccating conditions. Therefore, formulations have been developed to protect the nematodes from harmful environmental conditions (UV and desiccation). Examples of protective formulations include "Barricade" fire gel and polyacrylate hydrogel. However, information on the the impact of these formulations on storage capacity of the nematodes was lacking. Thus, our objective was to study the effects of Barricade and polyacrylate hydrogel on the storage ability of three beneficial nematode species. Compared to controls with no formulation, both formulations caused significantly higher survival of the nematodes under normal cold storage (10 C) during a 2-8 week period. Therefore, the protective formulations are advantageous because they protect beneficial nematodes in the field post-application, and also enhance survival of the nematodes during storage.

Technical Abstract: Entomopathogenic nematodes (EPNs) used as biocontrol agents, are sensitive to ultra-violet (UV) light, high temperatures and desiccation. Thus, formulations have been developed to protect EPNs during application. However, the ability of these formulations to enhance storage capacity has not been investigated. This study analysed storage capacity (survival and efficacy) of EPNs, (Heterorhabditis bacteriophora (SGI 245), Steinernema tophus (ROOI 352) and Steinernema innovationi (SG I35) produced either in vivo or in vitro and formulated in 2% gel of either Barricade® or potassium polyacrylate hydrogel (PPH). The formulations were stored at 10°C and survival of the IJs was evaluated at two weeks intervals for eight weeks. The efficacy of formulated nematodes was tested using Tenebrio molitor. After two weeks, the controls had 0% IJs survival for all the isolates, whereas the gel formulations exhibited 58-76%. The three isolates in both the Barricade® gel and PPH formulations had 37 - 69% IJs survival at six weeks and 0 - 13% after eight weeks. Both formulations of the three isolates were 60 - 90% effective at six weeks. The in vitro produced IJs had a higher survival than the in vivo produced IJs for S. innovationi and H. bacteriophora. However, the in vivo produced IJs were more effective at killing mealworms than the in vitro produced EPNs for H. bacteriophora but not the Steinernema spp. In conclusion, Barricade® and PPH gel formulations substantially increased survival of the three EPN species during storage.