Background: Trichoderma asperellum (Ascomycota: Hypocreaceae) is a globally recognized soil fungus due to its broad-spectrum antimicrobial and plant growth-promoting properties. To increase the availability of local strains, soil samples from a dragon fruit farm in Villanueva (Misamis Oriental, Philippines) were collected and baited using the insect-baiting technique. Results: Using the baiting technique, T. asperellum strain, RMCK01, was isolated. The strain was characterized using morphological and molecular data and its biological control potential was tested using different conidial concentrations on the last larval instar of the super worm, Zophobas morio (Fabricius, 1776) (Coleoptera: Tenebrionidae). The ITS1 sequences of T. asperellum RMCK01 were 100% identical to the sequences of other T. asperellum isolates reported from Vietnam, India, Thailand, and China. In addition, T. asperellum RMCK01 was particularly efficient against Z. morio larvae. On day 21, 88.87%, 88.07%, and 86.73% of insects died when treated with a suspension containing 6 × 10⁸, 3 × 10⁹, and 2.68 × 10⁷ conidia/ml, respectively. Conclusion: The study highlights the potential of this fungal isolate as a biocontrol agent against insect pests.

Entomopathogenic nematodes (EPNs) are commonly used biocontrol agents of insect pests, with a wide range of commercially available isolates targeting specific pests. New isolates are, however, required to improve pest control across a wider range of environmental conditions for target pests, including emerging threats. We assessed the effect of temperature on survival and virulence of 17 Australian isolates of five EPN species (Heterorhabditis bacteriophora, Heterorhabditis indica, Heterorhabditis marelatus, Heterorhabditis zealandica and Steinernema feltiae) against larvae and pupae of the Queensland fruit fly, Bactrocera tryoni. All isolates still infected and killed larvae after infective juveniles (IJ) had been kept without insect hosts at 15 °C, 25 °C or 30 °C for two weeks, indicating their potential to remain viable under field conditions. However, the mean LD₅₀ value ranged from 35 to 150 and was generally lower at 15 °C than at 25 °C and 30 °C. Similarly, after IJs had been kept at 25 °C for 1–3 weeks without insect hosts, all isolates infected B. tryoni larvae, with mean LD₅₀ values ranging from 25 to 144. Interestingly, 15 isolates infected and killed B. tryoni pupae after one week, with a mean LD₅₀ value between 130 and 209, but only two isolates after two weeks, with a mean LD₅₀ value between 229 to 209. No pupal mortality was seen after three weeks. In absence of hosts, EPNs survived longer at 15 °C and 25 °C than at 30 °C. Complete EPN mortality occurred after nine weeks at 30 °C, and after 18 weeks at 15 °C and 25 °C, except for some survival in one S. feltiae isolate (Sf.ECCS). Overall, six isolates of H. indica (Hi.HRN2, Hi.LMI2, Hi.QF6), H. bacteriophora (Hb.HIE), H. zealandica (Hz.NAR1) and S. feltiae (Sf.ECCS) performed best and need further testing as potential biocontrol agents against B. tryoni under semi-field and field conditions.