Reproductive phenology and feeding patterns of Listronotus maculicollis during spring emergence: Implications for spring management

Abstract

The annual bluegrass weevil [Listronotus maculicollis (Kirby)] is a severe pest of golf course turf in North America. Most turf managers attempt to minimize larval damage by targeting adults with insecticides upon emergence from overwintering habitats in spring. Fluctuations in weather often create asynchronous emergence patterns that lead to inefficacious applications. We sought to describe L. maculicollis reproductive phenology to determine when mating and oviposition occur to better time insecticide applications. Dissections were performed on adults collected weekly from golf course fairways and tees between adult emergence and the end of the first generation over a 3‐yr period. Most females emerged with well‐developed reproductive systems, though <40% were mated. Fewer than 20% of males were mature upon emergence and required 5–8 wk after first emergence before all captures displayed mature reproductive systems. Few adults were found to have fed between emergence and adult peak, suggesting that systemic insecticides applied during the migration are not likely to be ingested. In caged oviposition studies, females survived up to 15 wk, with oviposition occurring as late as 14 wk. Average total fecundity ranged between 60 and 90 eggs per female with most oviposition occurring between the start of the experiment and 5 (2013) or 8 wk (2012). A strong correlation between growing degree days per week and eggs per female per week was detected over this period. Our findings suggest that insecticide applications targeting adults to reduce asynchronous larval development and damage should not be applied prior to peak emergence.

Insecticidal Activity of a Petroleum-Derived Spray Oil and an Organosilicone Surfactant on Listronotus maculicollis (Kirby) Adults in Laboratory and Greenhouse Bioassays

“…Turfgrass managers attempting to control ABW with Civitas may wish to limit high-rate applications or increase the interval between applications. ABW adults may emerge from overwintering in spring over several weeks [28,33], which may often result in multiple insecticide applications to reduce oviposition and future larval damage if not well-timed. Applications of high rates of Civitas in short time frames (<2 weeks) could lead to declining turfgrass health, as the Harmonizer alone has been documented to lead to decreases in stand density over time [32].…”

“…The Harmonizer makes identification of the material on and within the insect possible with a dissecting microscope by observing the process of pigment penetration through the insect cuticle and diffusion inside the insect hemocoel and internal organs at different times after treatment. Dissections were performed using the methodologies described in McGraw et al (2020) [28].…”

Evaluation of nitrogen fertility and plant growth regulator impacts on annual bluegrass weevil (Listronotus maculicollis) oviposition and larval survivorship

“…A constant pressure of 28 psi was used to deliver the products in a total volume of 407 L ha -1 . Weevils were introduced into plots to coincide with the period when L. maculicollis populations were at peak densities in spring and when males and females were sexually mature (∼ 150 GDD [˚F], March 1 start, 10 ˚C base temperature, Watch Dog weather station, Spectrum Technologies) (McGraw et al, 2020). Each replicate housed six 10-cm diameter PVC cylinders (7.5 cm high) recessed 2.5 cm into the ground.…”