Phlyctinus callosus (Schönherr), the banded fruit weevil, is a key pest of deciduous fruit and grapevine in the Western Cape province of South Africa. Entomopathogenic nematodes (EPNs), as a biocontrol agent, are found to be effective in controlling both soilborne and above-ground insect pests. Different EPN species were screened for virulence against different life stages of P. callosus, followed by a field trial, in which Steinernema yirgalemense was applied at different concentrations. S. yirgalemense, Heterorhabditis noenieputensis and the exotic Steinernema feltiae gave good control of P. callosus larvae at 100 infective juveniles per insect, with no significant difference between treatments. In the case of P. callosus pupae, Heterorhabditis indica (70%) and Heterorhabditis baujardi (67%) differed significantly (P < 0.05) in their control, compared with H. noenieputensis (55%). H. indica (95%) and S. yirgalemense (94%) gave significantly higher (P < 0.05) control of P. callosus adults, compared with the three other nematode species tested. In the field trials, S. yirgalemense, at 20 and 40 infective juveniles/cm 2 , gave 69% and 78% control of P. callosus larvae after 48 h of exposure, respectively. The results indicated that all EPNs tested were effective against the immature and adult stages of P. callosus, with differences in mortality among the EPN species tested. S. yirgalemense, at low concentration, can effectively control P. callosus under field conditions, but large-scale field trials are recommended to demonstrate the potential use of this biocontrol agent within integrated pest management programmes.

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Tomato (Solanum esculentum) is one of the vegetable crops grown by both smallholder and commercial farmers in the Kingdom of Eswatini. Tomato leaf miner, Tuta absoluta M. is a major insect pest of tomatoes resulting in reduced tomato yields throughout the country. The study investigated the virulence of two subtropical EPN species on T. absoluta larvae. Steinernema yirgalemense and S. jeffreyense at different concentrations (0, 20, 40, 60 IJs/insect) were screened for efficacy (i.e. mortality rate) against larvae of T. absoluta in laboratory bioassays. Results obtained showed that S. yirgalemense and S. jeffreyense were able to kill T. absoluta larvae without significant differences between the two EPN species in 24-well bioassay trays. Significantly higher (p < 0.05) mortality was observed when 60 IJs/ insect was used. The combination of S. yirgalemense at 60 IJs/ insect (100%) and S. jeffreyense at 60 IJs/insect (98.3%) resulted in significantly higher (p < 0.05) mortality, compared with the other four combinations of EPN and concentration tested. In the leaf bioassays, S. yirgalemense (58.8%) resulted in significantly higher (p < 0.05) mean mortality compared to S. jeffreyense (46.4%). Steinernema yirgalemense at 60 IJs/insect resulted in significantly higher mean mortality compared to the other EPN and concentration combinations in the leaf bioassay. The results indicated that both EPNs tested were effective against T. absoluta larvae. Steinernema yirgalemense at 60 IJs/insect can effectively find T. absoluta larvae inside leaf mines, but large-scale field trials are recommended to demonstrate the potential use of the biocontrol agent within integrated pest management programs.