# How Do Host Plants Mediate the Development and Reproduction of Phytoseiulus persimilis (Acari: Phytoseiidae) When Fed on Tetranychus evansi or Tetranychus urticae Koch (Acari: Tetranychidae)?

## TL;DR

This study explores how host plants affect the predator Phytoseiulus persimilis when feeding on two Tetranychus pest species, revealing that potato plants reduce the predator's effectiveness.

## Contribution

The study identifies that T. evansi is unsuitable prey for P. persimilis and that potato plants negatively impact predator performance.

## Key findings

- Phytoseiulus persimilis has significantly lower reproductive potential when fed Tetranychus evansi compared to Tetranychus urticae.
- Potato plants reduce the intrinsic rate of increase of P. persimilis by 55.56% when T. evansi is the prey.
- Performance metrics like oviposition and egg production are worse when T. evansi is reared on potatoes.

## Abstract

Tetranychus evansi Baker et Pritchard and Tetranychus urticae Koch (Acari: Tetranychidae) are significant agricultural pests. Phytoseiulus persimilis (Acari: Phytoseiidae) is one of the most effective natural enemies for controlling Tetranychus pests. This study compared the influence of host plants on the biological performance of P. persimilis when preying on these two Tetranychus species raised on either bean or potato plants. A key finding of this study was that T. evansi does not serve as suitable prey for P. persimilis. Furthermore, potato plants were shown to indirectly reduce the effectiveness of P. persimilis by adversely affecting the pest population itself. This research contributes to a better understanding of the complex interactions among crops, pests, and their natural enemies—insights that are important for developing more effective pest management strategies.

In this study, P. persimilis was provided with T. evansi and T. urticae that had been reared on either bean or potato plants to investigate the effects of both prey and host plant species on the predator’s growth, development, and fitness. The results indicate that the reproductive potential of P. persimilis populations fed T. evansi was significantly lower than that of populations fed T. urticae from the same host plant (p < 0.01). Phytoseiulus persimilis fed T. evansi that had been reared on potatoes showed poorer performance in oviposition period, post-oviposition period, daily egg production, and total egg production compared to those fed T. evansi reared on beans (p < 0.01). The intrinsic rate of increase (rm) of P. persimilis fed on T. evansi reared on potato was 0.08, which was 55.56% lower than that of populations fed on T. evansi reared on beans. This study sheds light on the complex interactions among host plants, pests, and their natural enemies, thereby providing a theoretical basis for developing more effective and sustainable management strategies against T. evansi that take these intricate ecological relationships into account.