BACKGROUND: Several phytoseiid species can potentially control the citrus rust mite (CRM). Their effectiveness varies, however, as do their intraguild interactions. Under laboratory conditions, Euseius stipulatus, E. scutalis and Iphiseius degenerans preyed effectively on CRM, whereas Amblyseius swirskii and Typhlodromus athiasae had no effect on CRM. In combination with A. swirskii, Euseius numbers were reduced due to intraguild predation, and consequently CRM suppression was less effective. In the field, predatory mite species can be variably provisioned by windborne pollen released from cover crops such as Rhodes grass (RG). We aimed to determine the effects of RG on the phytoseiid community in two field experiments, on different cultivars (pomelo and Shamouti orange). We also tested these communities for negative interspecific abundance relationships that are expected if their respective laboratory-observed intraguild interactions are manifested in the field. RESULTS: Overall, on pomelo, we observed a dominance of A. swirskii, relatively low E. stipulatus and high CRM abundances. Amblyseius swirskii and E. stipulatus abundances were both elevated near RG, despite apparent intraguild predation by A. swirskii. Conversely, T. athiasae abundances were lower near RG, likely due to predation by A. swirskii. On Shamouti, E. stipulatus abundances were much higher than on pomelo and were not negatively related to A. swirskii abundances. There, RG increased E. stipulatus abundance, and CRM was reduced. CONCLUSION: RG cover cropping can enhance CRM control, depending on variation in intraguild interactions among phytoseiids, particularly between A. swirskii and E. stipulatus. These may be modulated by climatic and/or cultivar effects.
Bibliographical noteFunding Information:
The authors express their gratitude to Noam Yehiely from the Akko experimental farm and Yonatan Abrahams from the Extension service (Ministry of Agriculture) for their input and endless positive energy and to Mehadrin for their assistance and access to the plot in Pardesiya. The authors thank the R&D staff at BioBee for their technical support and for providing the predatory mites for the numerous releases. This work was supported by the Israeli Plant Production and Marketing Board, the Chief Scientist of the Israeli Ministry of Agriculture, research project 864-0045-08 and USAID Middle East Regional Cooperation grant number TA-MOU-10-M30-057. This manuscript is a contribution of the Institute of Plant Protection and the Institute of Plant Sciences, Volcani Centre, ARO, Israel.
© 2018 Society of Chemical Industry
- Amblyseius swirskii
- Euseius stipulatus
- Phyllocoptruta oleivora
- Typhlodromus athiasae
- intraguild predation
- mite community ecology
- windborne pollen provisioning
ASJC Scopus subject areas
- Agronomy and Crop Science
- Insect Science