Plant-Associated Fungi Effects on Boll Weevil Growth

Our goal was to analyze whether cotton plants treated with plant-associated fungi can interfere with boll weevil growth and survival. We compared the performance of weevils by infesting 45-day old cotton plants grown from seeds treated with one of several plant-associated fungi (Chaetomium globosum TAMU520 and TAMU559, Phialemonium inflatum TAMU490, Acremonium lolii TAMU505, and Beauveria bassiana Bb) versus untreated control plants in cages under greenhouse conditions. Each cage contained one plant along with one fertilized boll weevil female and was checked daily to collect abscised squares and check for oviposition. From the infested squares, we recorded the number of larvae, body size, pupal weight, growth rate (pupa or adult weight divided by the days until emergence), longevity (days to adult death), sex ratio, and % mortality (larvae, pupae, and adults). We observed negative effects of fungal treatments on time to adult emergence, with weevils taking longer to reach the adult stage on some treatments relative to untreated controls. This result illustrates the potential for fungal cotton treatments to extend weevil generation times and negatively affect population growth in the field.