Range delimitation and flight phenology for Archips goyerana (Lepidoptera: Tortricidae), a significant defoliator of baldcypress.

Abstract

Forested wetlands support diverse biota and provide a wide range of ecosystem services. Archips goyerana Kruse (Lepidoptera: Tortricidae) is a native pest that defoliates baldcypress (Taxodium distichum var. distichum (L.) Rich.; Cupressaceae) and pondcypress (Taxodium distichum var. imbricarium (Nuttall); Croom), 2 keystone trees throughout forested wetlands of the southeastern United States. Outbreaks of the A. goyerana have been isolated to southeastern Louisiana, where they have caused reduced growth, crown dieback, and limited tree death. However, aerial detection surveys indicated that severe defoliation by A. goyerana has been affecting wetlands further east within the region. Given the possibility of expanding outbreaks, it is important to understand the timing of A. goyerana activity, duration of the flight period, and efficacy of different trap types to guide survey efforts. We deployed traps in a paired design, one bucket trap and one delta trap, each baited with synthetic A. goyerana sex pheromone at 30 sites throughout the range of baldcypress. Over 2 field seasons, we checked traps weekly and quantified the number of A. goyerana caught per trap type, ability of each trap type to detect a single moth (trap sensitivity), and growing degree days, using a base temperature of 5 °C accumulated at the onset, peak, and cessation of the flight period. We found that delta traps caught more moths but sensitivity of traps was equal between the 2 trap types. Analyses of phenology indicated that A. goyerana flight occurred between ~1,000 and 1,600 growing degree days. Optimizing trapping practices for A. goyerana may improve detection of endemic populations and help identify areas potentially at risk of experiencing outbreaks.