Sphenophorus levis behavior: repellency to insecticide treatment and nocturnal adult activity and location pattern

Abstract

Abstract Sphenophorus levis is a difficult to control pest in sugarcane that causes great damage to the subterranean part of the plant. Low insect control has been a result of the pesticide application technology adopted but also because of the lack of studies regarding the pest’s behavior. This research aimed to examine the repellency of insecticides to S. levis adults and to evaluate the activity and location behavior of S. levis adults under 24 hour-observations. Repellency studies were conducted in free-choice tests providing treated soil with lambda-cyhalothrin + thiamethoxam and untreated soil as choice options to S. levis adults. Insect activity and location behavior studies were assessed by hourly observations of S. levis adults in containers with soil and sugarcane plant. Results indicated S. levis adults were not repelled nor attracted to soil treated with lambda-cyhalothrin + thiamethoxam. Additionally, insects presented nocturnal behavior with most activities (walking, digging and mating) starting at 18:00 pm until 2:00 am. An average of 20.7% of insects were out of the soil at night while the majority, 79.3%, remained inside the soil. During the day most insects, 95%, remained hidden in the soil. Exposed insects were primarily located on soil surface. According to these results, nocturnal insecticide applications may improve S. levis adult control due to greater insect activity and exposure at night.