Subterranean termites, Anacanthotermes ochraceus, are a widely distributed and mainly recognized in Saudi Arabia as agricultural pests and economically serious insects causing damage to wood structures. Because termites have a cryptic feeding habit and have developed resistance to several insecticides, the effectiveness of most synthetic insecticides against them has been diminished. This study was designed in laboratory using sawdust and sand bioassay to confirm six native entomopathogenic nematode (EPN) isolates' effectiveness including Steinernema feltiae NEM-29, S. feltiae AHN, Heterorhabditis indica NEM-19, H. indica NEM-18, H. bacteriophora NEM-26 and H. bacteriophora AHN22 against workers of A. ochraceus. Results revealed that termite worker mortality was higher in the sawdust bioassay than in sand bioassay. At both tested assay methods, S. feltiae had a significantly greater mortality rate, followed by H. indica and H. bacteriophora. The maximum mortalities (100% and 79.0%) was recorded for S. feltiae AHN at 1000 IJs/termite with lower LC50 values of 7.3 and 73.8 IJs/termites at 16 d-post exposure in sawdust and sand assay, respectively. All tested EPN strains reproduced successfully and emerged from dead A. ochraceus workers in 8-14 days with higher reproduction rate (22,193 IJs/termite) for S. feltiae AHN in sawdust bioassay. Conclusively, it has been discovered that native EPNs can control termites more successfully, presumably due to they have the ability to spread further infections via infected dead individuals and can directly interact with termite pests in the soil.

Decomposition and litterfall are the primary mechanisms by which plants release their organic matter and nutrients into the soil, which helps prepare the stage for beneficial pathways in the restoration of damaged ecosystems. Species selection and allocation for the successful use of litter in ecological agricultural fields relies on knowing the mechanisms of plant litter decomposition and its influence on soil nutrients, which are crucial aspects of the ecosystem material cycle. In current study, in-vitro dry matter digestibility (IVDMD) used for evaluating quality animal feed reveals some potential in the decomposition of organic matter estimated. Nevertheless, some consensual advantages as laboratory incubation, this methodology demands a validation procedure. Therefore, the present work aimed to validate the IVDMD methodology by comparison with field buried litter bag mass loss, for 27 organic materials with different origins and chemical quality. The results reveal significant differences among the organic materials studied, reflecting their chemical quality variation, with digestibility values varying between 10.1 gkg-1 in composted sewage sludge and 982.0 gkg-1 in pig meat meal. IVDMD presented high accuracy results for all studied periods, with best results observed for 28 days incubation period (r2adj = 0.959***). Taking the chemical fractions that participated in initial decomposition process the IVDMD is a potential indicator of a labile decomposable pool of organic materials. Considering the high accuracy, repeatability (CV = 4.6%) and practicability, the IVDMD is a reliable alternative to the litter bag method in field mass loss availability.