Glandless cotton: Developing tools to manage insect pests in New Mexico

Glandless cotton is much more susceptible to insect pests than glanded cotton which contains gossypol.  However, glandless cotton is attractive as a crop because the seed can be consumed by non ruminants and is thus worth approximately 10 times more than seed from glanded cotton.  Historically, pink bollworm and cotton bollworm were the key pests of cotton in New Mexico. Pink bollworm has been eradicated, but cotton bollworm may cause losses in glandless cotton.  Occassional insect pests such as beet armyworm might also cause losses.  Field trials were conducted from 2011-2013 to determine susceptibility to insect pests and to determine the impact on beneficials.   Low nitrogen plots were also compared to standard fertility treatments to determine if lower nitrogen would reduce attractiveness and survival with lepidopterous pests.  

Bollworm and beet armyworm survival was higher on glandless cotton with 85% vs 8% survival of bollworm and 51 vs 10% survival of beet armyworm on glandless vs. glanded cotton respectively. Survival of bollworm and beet armyworm was not lower in the low N plots which had 1573-1765 ppm petiole nitrate vs high N plots with 5211-6243 pmm.  Field damage was also not significantly lower in low N plots with 6.1% and 8.2% damaged squares in low and high N plots respectively.  There was no difference in predation to sentinel eggs in glanded and glandless plots.