Almost too small to see with the naked eye, thrips can be in your dry beans, and you’ll never know until you see cupping on leaves. Dry bean growers, especially in southwestern Nebraska, often apply insecticides for thrips, although little is known about the impact of thrips on production.
University of Nebraska-Lincoln (UNL) Master’s Student Aarju Aryal has been conducting research on thrips — slender insects with fringed wings that are only a few millimeters long — at the Crop IPM Entomology Lab at the UNL Panhandle Research, Extension and Education Center (PREEC) in Scottsbluff.
“They injure bean plants by feeding on and laying eggs in plant tissues, including leaves, flowers and pods. In addition, thrips can transmit plant viruses, causing diseases in dry beans,” Aryal said. “Warm, dry springs accelerate thrips population growth, leading to higher infestations.”
Aryal has been identifying thrips species in dry beans, comparing classes and varieties to determine which are good hosts for thrips and which tend to support higher or lower populations. She is also testing commonly used neonicotinoid seed treatments and foliar insecticides to evaluate how well they reduce thrips abundance and damage.
“We are looking beyond the crop itself, at the common weed species growing in and around bean fields, to identify which of them serve as alternative hosts where thrips populations can build up before moving into the dry beans,” she said.
Many growers plant seed treated with a neonicotinoid insecticide as a precaution against thrips. Later in the season, when leaf cupping caused by thrips feeding shows up in the field, a foliar spray of acephate often follows. Both of those management actions are made without knowing whether the treatment reduces thrips numbers or damage, and without knowing how much yield loss, if any, thrips would have caused had nothing been applied. Very little information exists on which thrips species feed on dry beans in western and southwestern Nebraska, or on how their feeding affects plant growth and yield. Those knowledge gaps leave growers investing in treatments with unknown returns.
Future studies will develop economic thresholds linking thrips abundance and crop injury to yield loss, helping growers determine when treatment is justified. Refining scouting methods and identifying vulnerable growth stages will support more timely, targeted and cost-effective management decisions.
The Crop IPM Entomology Lab at PREEC has been conducting research since 2024 to address critical knowledge gaps through a combination of field trials at the research station and laboratory studies. Through field sampling in 2024 and 2025, researchers identified two thrips species commonly feeding on dry beans across the Nebraska Panhandle: western flower thrips (Frankliniella occidentalis) and onion thrips (Thrips tabaci). The western flower thrips is the predominant species, present in dry bean fields throughout the growing season.
More information and updates on this research, including a webinar summarizing the major findings of the study, can be found in PREEC’s 2026 Dry Edible Bean Webinar Series. Additional research updates and information about ongoing work with thrips in dry beans are available on the Lai Lab and Entomology Program website.
