Managing Whitefly and Tomato Yellow Leaf Curl Virus (TYLCV) in Tomato Open-Field

Abstract

A field-scale integrated pest management (IPM) programme combining pre-plant soil solarization, reflective mulch, weekly pest and parasitoid monitoring, a parasitoid-informed action threshold, and selective insecticides was compared with a conventional chemical-intensive programme for management of Bemisia tabaci and Tomato yellow leaf curl virus (TYLCV) in open-field tomato. The study was conducted at CCRI Pirsabak during the 2024–2025 season using a randomized complete block design with four replicate 0.5-ha plots per system. Adult whiteflies were monitored weekly using sticky traps and direct leaf counts; immature stages were quantified from standardized leaf samples; and parasitoid emergence (Eretmocerus and Encarsia) was assessed after leaf incubation. Selective applications of buprofezin or spiromesifen were triggered when adult abundance exceeded five per leaf and the parasitoid-to-whitefly ratio fell below 1:10. At 60 days after transplanting, adult whitefly density averaged 4.8 per leaf under IPM compared with 9.2 under conventional management—a 47.8% reduction. Total parasitism increased from 12.6% to 56.6%, a 44.0 percentage-point gain. Seasonal insecticide applications declined from 11.0 to 5.2 (52.7% reduction), while active-ingredient use decreased by 62.9%. Marketable yield was 31.8 t ha⁻¹ under IPM and 28.6 t ha⁻¹ conventionally; the difference was not statistically resolved. TYLCV incidence declined by 52.0%, from 34.2% to 16.4%. Despite higher upfront costs for solarization and reflective mulch, absolute net return increased by PKR 92,000 ha⁻¹. These findings support a decision-based IPM programme that integrates prevention, biological conservation, and selective intervention. However, verification of block-level observations, diagnostic records, cost invoices, and original statistical outputs is essential before final adoption recommendations are made.