Responses of Dalbulus maidis (Delong & Wolcott, 1923) (Hemiptera: Cicadellidae) and non-target species to traps with different light spectra in maize fields

The maize leafhopper Dalbulus maidis (Hemiptera: Cicadellidae) is a key pest and vector of pathogens in Latin American maize, and its monitoring in the field currently relies mainly on yellow sticky traps, which present handling difficulties and low selectivity. This study evaluated LED-based light traps with different spectra and internal colors as alternatives for monitoring D. maidis while minimizing captures of non-target insects. Field trials were conducted in maize crops in Londrina, Paraná State, Brazil, in March 2023 and May 2025. The experimental design was a randomized complete block factorial (4 × 2 + 1): four light spectra × two internal trap colors + yellow sticky trap, in five temporal replicates. Traps were baited with LEDs emitting 372, 402 or 409 nm, or warm-white light (3000 K), and had either a white or black internal surface. Warm-white LEDs combined with a white internal surface captured 69-fold (2023) and 81-fold (2025) more D. maidis adults than yellow sticky traps; whereas 372 and 409 nm yielded captures similar to those of yellow traps. Spectra at 402 nm with a white background produced intermediate increases. Predatory insects were rarely captured (<1.5 individuals per trap on average) and did not differ among spectra or internal colors. Warm-white traps with white background also captured the highest numbers of other cicadellids, whereas moths were predominantly attracted to 402 and 409 nm, with relatively low capture under warm-white light. Overall, warm-white LED traps with a white internal background substantially improved D. maidis capture compared with yellow sticky traps, with minimal impact on predators and reduced moth capture. This configuration is a promising option for enhancing maize leafhopper monitoring in the field, although the high attraction of other leafhopper species may constrain its use in future automated detection systems.