Analyses of Boll Weevils Captured near Hay Bales

Boll weevils re-infesting cotton fields in Louisiana were often correlated with the movement of large hay bales in the area.  In Texas, boll weevils were collect in pheromone traps that were placed upwind from hay bales that were in varying stages of decay and in numbers ranging from 10 to over 30.  Boll weevils were collected in the Uvalde District of the Texas Boll Weevil Eradication Foundation's South Texas Winter Garden Zone.  To indicate possible refuge of the weevils near or in hay bales, the weevils were examined for pollen grains, fungal spores and phytoliths (plant cells).  Overall 98 pollen grains from 38 different taxa were found in the samples.  No one pollen type was found in all samples.  More grass pollen grains (25 including 2 corn pollen grains) were found than any other taxon.  Following the grasses was the “low spine” Asteraceae with 14 grains, and then the Cheno-Ams and Ulmus sp. (elm), both with 7 grains each.  Cotton pollen was found in two weevils.  The diversity of pollen taxa is representative of the vegetation in the Uvalde District, Texas which is in the South Texas Plains Vegetation Zone.  No grass phytolith was seen in the samples.  Seven spore types and 44 spores were found in the samples and one type of fungal hypha.  No single spore type occurred in all the samples.  One Puccinia (wheat rust) and a Stemphylium spore were found in the samples.  The lack of grass phytoliths, the generalistic habit of the fungi and the pollen taxa present, do not indicate that these weevils existed for long periods within or near the hay bales.  However, additional research and a greater number of weevil samples are needed to determine if these techniques can be used to distinguish weevils associated with hay bales.