Evaluation of Reflective Mulch and Soil Solarization, for Suppression of Thrips and Tomato Spotted Wilt Virus in Field-Grown Tomato

Abstract

Reflective mulch and soil solarization were evaluated individually and in combination as non-chemical components of an integrated pest management (IPM) programme for tomato. A field experiment was conducted at CCRI Pirsabak during the 2024–2025 season using a randomized complete block design with four replications. Four treatments were compared: silver-on-black reflective mulch, pre-plant soil solarization (four weeks), their combination, and standard black plastic mulch as a control. Thrips density was assessed at 30, 60, and 90 days after transplanting (DAT), and Tomato spotted wilt virus (TSWV) incidence was confirmed by DAS-ELISA. Soil temperature during solarization was monitored at 5, 10, and 15 cm depths. Marketable yield, gross revenue, and net return were calculated. The combined treatment consistently produced the lowest thrips density, with 1.2 thrips per leaf at 30 DAT compared with 6.4 in the control—an 81.3% reduction. At 90 DAT, TSWV incidence was 12.8% under the combined treatment versus 32.4% in the control, representing a 60.5% reduction. Solarization raised soil temperature to a maximum of 50.1°C at 5 cm depth during week 3. Marketable yield was highest under the combined treatment at 32.8 t ha⁻¹, a 46.4% increase over the control (22.4 t ha⁻¹). Despite the highest input cost, the combined treatment generated a net return of PKR 2.91 million ha⁻¹—PKR 720,000 ha⁻¹ greater than the control. These results demonstrate that integrating reflective mulch with soil solarization provides complementary suppression of thrips and TSWV while significantly improving tomato yield and profitability. The combined approach offers a promising, reduced-insecticide strategy for sustainable tomato production, though verification of material costs, virus diagnostics, and multi-season performance is recommended before wide-scale adoption.