Biological control of Callosobruchus chinensis (Coleoptera: Chrysomelidae) in stored chickpeas through the release of natural enemies

•Adult parasitoids freely searched for hosts under up to 150 cm of chickpeas.•Parasitoids kept bruchid populations below 10% that of the control.•Parasitoid wasps can be an alternative to pesticides for controlling C. chinensis. In this study, two predatory mites and two parasitoid wasps were evaluated for their effectiveness in controlling Callosobruchus chinensis (Coleoptera: Chrysomelidae), a common pest in stored chickpeas. The predatory mite Amblyseius swirskii (Acari: Phytoseiidae) preyed on the bruchid’s eggs but did not consume a large amount; the mite Blattisocius tarsalis (Acari: Ascidae) did not consume C. chinensis eggs. However, the larval parasitoids Anisopteromalus calandrae and Lariophagus distinguendus (Hymenoptera: Pteromalidae) were effective at reducing the bruchid’s larval population, producing mortality rates above 90% in controlled conditions (28 ± 2 °C, 75 ± 5% relative humidity [RH]). In tubes of 20-cm diameter filled with 9–35 kg of chickpeas, both parasitoids were able to parasitize the host at depths of 40, 100, and 150 cm, even when larvae were offered simultaneously at all depths. This indicates that parasitoids will probably be able to locate hosts at least at 150 cm of distance in a storage facility. A. calandrae was similarly effective at reducing the bruchid population at different parasitoid-to-host ratios (1:7, 1:15, 1:30, and 1:60). Moreover, A. calandrae efficiently reduced C. chinensis populations when released in 25-kg commercial polypropylene bags of chickpeas in simulated warehouse conditions (27 ± 2 °C and 65 ± 4% RH). This is the first time that A. calandrae and L. distinguendus are shown to be effective biological control agents for the integrated management of C. chinensis in stored chickpeas and can be an alternative to the application of pesticides for maintaining low bruchid population levels.