Relevance of local scale factors in winter host-plant selection by the rice pest Tibraca limbativentris (Hemiptera: Pentatomidae)

Abstract

Tibraca limbativentris is a major stink bug pest in paddies of the Neotropics. In Argentina, its populations overwinter in twelve host‐plant species that occur inside rice fields. However, it's unknown if there are local scale variations in the abundance of T. limbativentris. Likewise, the role of host‐plant community composition (HpCC) as a factor involved in the winter host‐plant selection by the insects is poorly understood. The aims of this work were (a) to assess variations at local scale on the abundance of T. limbativentris in the context of winter HpCC and incidence of entomopathogenic fungi (EPFs) and (b) to assess the abundance of T. limbativentris considering the relationship between the height of plants of rice cultivars present in target sites during summer, and the height of the hosts selected by T. limbativentris during winter in grassland adjoining rice plots. Sampling was carried out during summer–winter in different commercial rice fields, to assess winter abundance of T. limbativentris, HpCC in grasslands adjacent to rice plots and incidence of EPFs. Height measurements of winter hosts and summer rice plants in target plots were taken. Our results show that HpCC differed at the local scale, with significant differences in stink bug abundance between winter hosts in each site. Also, we found differences in the action of EPFs species recorded on the insects and variations in plant height between host species. A positive correlation was obtained between the height of the different rice cultivars used during spring–summer in target sites and the height of the hosts selected by T. limbativentris near to these plots during winter. This shows that the height of the rice cultivar could be a factor related to the local selection of winter hosts by T. limbativentris. These results serve as a framework for future research, contributing to integrated pest management for target sites.