Aerial application methods control spider mites on corn in Kansas, USA

Area of Science:

• Agricultural Entomology
• Pest Management
• Crop Science

Background:

• Banks grass mite (Oligonychus pratensis) and two-spotted spider mite (Tetranychus urticae) are significant pests of irrigated corn in Kansas, leading to yield losses.
• These mites cause damage through foliage loss, stalk breakage, and kernel shrinkage, impacting overall crop productivity.

Purpose of the Study:

• To evaluate the efficacy of aerial application methods for controlling spider mites in a commercial corn field.
• To compare the effectiveness of conventional flat-fan hydraulic nozzles versus aerial electrostatic nozzles for pesticide delivery.

Main Methods:

• Aerial application of dimethoate and Lorsban Advanced with a nonionic surfactant using two nozzle types at different volumes per hectare.
• Assessment of spray droplet spectra using water-sensitive paper samplers and image analysis software.
• Efficacy evaluation through objective spectral analysis of corn leaves and subjective damage ratings by crop scouts.

Main Results:

• Both conventional and electrostatic nozzles, with spray droplet volume median diameters (VMD) of 283 µm and 210 µm respectively, effectively controlled spider mites.
• Objective spectral analysis and subjective damage ratings confirmed significant mite control compared to an untreated check.
• Different application volumes (28.1 L/ha for conventional, 9.3 L/ha for electrostatic) were used, demonstrating successful pest management outcomes.

Conclusions:

• Aerial application of insecticides using both conventional and electrostatic nozzles is an effective strategy for managing spider mites in corn.
• The study provides valuable data on spray droplet characteristics and their impact on pest control efficacy in agricultural settings.
• Findings support the use of optimized aerial application techniques to mitigate economic losses caused by spider mites in corn production.