Last year, we tracked the arrival of the invasive kudzu bug to Maryland kudzu patches and soybean fields. We found populations of the bug across all of the southern counties west of the Chesapeake, and two counties on the Eastern Shore. For the summer of 2014, we have been tracking populations found last summer and monitoring any spread northward. We have been sampling patches of kudzu vines along the border of the 2013 range of the insect across Prince George's, Montgomery, and Howard Counties. Our goal for this summer is to determine the timing of the kudzu bug life cycle in Maryland, including measuring generation times and changes in population size and demographics. We have conducted our sampling since April, and have so far only recovered one adult kudzu bug from sites that had kudzu bug populations last year. No eggs or nymphs have been found, indicating that many of the local populations of kudzu bugs may not have persisted through the harsh winter of 2013/14.
Or sampling methods at each site include using clear sticky traps over white pvc tubes, sweeping vegetation with an insect net, and collecting sections of vines to return to the lab. The sticky traps are left for a week to continuously monitor for adults, which are attracted to white surfaces, and would get stuck to the trap. Sweeping with the insect net is an efficient way to sample large portions of the kudzu patch for mobile adults, which tend to fall off of kudzu vines when disturbed, and would be caught in the net. The sections of vine that are returned to the lab are screened visually for smaller nymphs and egg masses, that may be overlooked in the field. So far all of our sampling trips except one have returned with no insects recovered from kudzu patches that had large, reproducing populations of kudzu bugs at the end of the summer of 2013.
So far our surveys suggest that winter weather was too harsh for most of the kudzu bugs in Maryland, due in part to extreme cold temperatures from the polar vortex that was experienced in January. Kudzu bugs are far from being eradicated in the state however, as extra surveys outside of our repeated, weekly collections have found at least one population of kudzu bugs surviving and reproducing on kudzu vines in Talbot County, near St. Michaels.
Our surveys of kudzu vines will continue through the remainder of the summer, despite extremely low numbers. There is still the possibility for insects to re-colonize kudzu patches from nearby sources before the end of the season, and the onset of senescence in kudzu vines. We will continue to report updates on kudzu bug populations through our surveys. We could also use your help to widen our surveys for the insect around the state, as we do not have the capacity to cover the entire state this summer with our sampling efforts. If you find kudzu bugs in kudzu vines or soybean fields around you, please report them here to our website. Your reports will help us to track this invasive pest through Maryland, and help to prepare for the possibility of a rebound in its population in the future.