Patrick Maris won the PhD student competition with a presentation titled Implementing Sweep Nets in Rice Water Weevil Scouting and the Efficacy of Foliar Insecticides for Rice Water Weevil Control. Rice water weevil (Lissorhoptrus oryzophilus: Kuschel) is the most important insect pest of early growth stage rice in Arkansas. The University of Arkansas Cooperative Extension Service recommends that a foliar insecticide application be made when 50 to 60 percent of new leaves show feeding scars from adult rice water weevil (RWW). Scouting by observing leaf scarring is time consuming and has been seen to be inconsistent with resulting larval populations. Scouting with a sweep net increases efficiency and allows the scout to directly quantify the adult RWW population present in the field which could allow them to make better management decisions in regard to controlling the pest. Previous studies have shown that the time of day can influence the insect populations quantified when scouting with a sweep net. In 2023, 2024, and 2025 a study was conducted to determine the effect of sampling time on the number of adult RWW populations caught using a sweep net. Plots were sampled at 7:00 am, 12:00 pm, and 5:00 pm, 24-hours before the permanent flood was established, three, 7, 10, and 14 days after the flood was established. The number of adults collected using a sweep net did not change between the morning and mid-day sample timings but did significantly increase in the evening sample timing. Sampling in the evening showed a consistent increase in the strength of the relationship between adults and larvae and adults and yield reduction. In another study the efficacy of foliar insecticides for control of RWW was tested. Insecticides tested include Warrior II (lambda-cyhalothrin), belay (clothianidin), Vantacor (chlorantraniliprole), and Endigo ZCX (lambda-cyhalothrin + thiamethoxam) which were applied either pre or post-flood. The pre-flood application of Endigo ZCX provided control of RWW adults when compared to all other pre-flood treatments. All insecticide treatments reduced larval populations when compared to the untreated check. No differences in control were observed between post-flood insecticide applications for control of adult RWW but all insecticide treatments reduced larval populations when compared to the untreated check.
