# Effect of Silicon on the Biology and Reproductive Fitness of Tetranychus macfarlanei Baker and Pritchard (Acari: Tetranychidae) on the Country Bean (Lablab purpureus L.)

## TL;DR

This study shows that adding silicon to country bean plants reduces the reproduction and survival of red spider mites, suggesting it could help control these pests.

## Contribution

The study demonstrates that silicon application significantly suppresses the reproductive fitness of Tetranychus macfarlanei on Lablab purpureus.

## Key findings

- Silicon at 56 ppm increased the immature period and reduced the lifespan and oviposition period of mite females.
- Egg production per female dropped from 94.62 at 0 ppm to 42.29 at 56 ppm silicon.
- Life table parameters like r, R0, λ, and GRR decreased with higher silicon concentrations, showing reduced reproductive potential.

## Abstract

The red spider mite, Tetranychus macfarlanei, is a significant pest of various crops, and silicon (Si), a beneficial micronutrient, serves as a physical defense against herbivores when accumulated in plant tissues. This study examined the effects of silicon on the biology of T. macfarlanei on Lablab purpureus plants treated with 0 ppm (control), 28, and 56 ppm silicon concentrations. The results showed that silicon treatments notably affected mite development. At the highest concentration of 56 ppm Si, females exhibited the longest immature period, shortest lifespan, and shortest oviposition period. Egg production per female was highest at the 0 ppm Si level (94.62) and lowest at the 56 ppm Si concentration (42.29). Life table parameters, including the intrinsic rate of increase (r), net reproductive rate (R0), finite rate of increase (λ), and gross reproductive rate (GRR), declined progressively with increasing silicon concentrations. Compared to the control (0 ppm Si), the highest silicon level resulted in reductions of approximately 24% in r, 55% in R0, 4% in λ, and 27% in GRR, indicating a substantial negative impact of silicon on the reproductive potential of T. macfarlanei. These findings suggest that higher silicon levels effectively suppress T. macfarlanei populations and may be useful in integrated mite management strategies.