The First Standardised Sampling Plan Designed to Scout Dalbulus maidis (Hemiptera: Cicadellidae) Adults in Corn Crops Using Yellow Sticky Traps

The corn leafhopper Dalbulus maidis (Hemiptera: Cicadellidae) is one of the main pests in corn crops causing yield reductions of up to 70%. Dalbulus maidis primarily damages corn by transmitting pathogens. Direct plant damage is caused by sap suction and toxin injection. Sampling corn fields to determine the D. maidis density for decision-making systems can be challenging due to field size, time and cost. Yellow sticky traps (YST) are commonly employed to determine the presence and density of D. maidis because they are easy to use and allow quick and low-cost assessment. This study aimed to propose and evaluate a new sampling plan for D. maidis in corn crops using YST. This research was carried out in commercial corn crops in the Brazilian Atlantic Forest and Cerrado biomes for 3 years. The pest density in traps and on plants were moderately (r = 0.54–0.66) and significantly (p < 0.0001) correlated. The density evaluated in the traps showed relative variance of less than 25% and sampling time of up to 2 min per sample unit. The negative binomial distribution was adequate to represent the D. maidis density probability distribution for the YST sampling method with K common (2.8979) among all the fields evaluated. The sampling plan consisted of installing one trap every two hectares. The plan's total cost ranged from US$/ha 0.41 to 0.50, with a total sampling time of up to 2.5 min/ha. We propose this new sampling plan for D. maidis, which is suitable for incorporation into management programmes in corn crops, as it is representative, accurate, fast and low cost.