|Brewer, Michael - Texas A&M University|
|Anderson, D - Texas A&M University|
|Armstrong, John - Scott|
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/3/2013
Publication Date: N/A
Interpretive Summary: The feeding injury from a cotton pest called the verde plant bug was studied under field enclosures for a one-week period during early and late bloom to determine the relationship between the number of insects released and the loss in lint, seed and the development of boll rot. When cotton plants were infested during early bloom, a linear loss releationship was established between the number of insects enclosed and the loss of cotton fruit, lint yield and boll rot that occurred. Lower numbers of insects resulted in low fruit loss and boll rot with step increases in these variables with increasing verde plant bugs enclosed. Lint and seed yields showed a corresponding decline from 0.5 bugs per plant to 4 bugs enclosed per plant. When plants were infested during late bloom, as opposed to early bloom, less detectable differences in yield and boll rot were observed. The effects of enclosing the plants was also studies and found to be negligiable. The results of our study can be used to further define the economic threshold for treating verde plant bugs with insecticides to reduce both yield loss in lint and seed, and from boll rot.
Technical Abstract: The verde plant bug, Creontiades signatus Distant (Hemiptera: Miridae), has emerged as a threat to cotton in South Texas, causing boll damage similar to boll-feeding stink bugs (Hemiptera: Pentatomidae). Verde plant bugs were released into caged cotton for a one-week period to characterize the effects of insect density and bloom period of infestation on cotton damage and yield. When plants were infested during early bloom, a linear decline in fruit retention and boll load, and a linear increase in boll damage and associated cotton boll rot were detected as verde plant bug infestations increased from an average infestation of 0.5 to 4 bugs per plant. Harvested lint and seed yield per plant showed a corresponding decline. Fruit retention, boll load, and yield were not affected on plants infested at peak bloom, even though boll damage and cotton boll rot increased at this later infestation period. Incidence of cotton boll rot, that has an association with verde plant bug feeding, was low to modest (<1% to 12% of bolls with disease symptoms), as moderate to severe drought stress persisted throughout the study. Cage effects were minimal: a 10% fruit retention decline was associated with caging, and the effect was not detectable in the other measurements. Overall, reduced fruit retention caused by verde plant bug was an important contributor to yield decline, and damage potential was greatest during the early bloom period of infestation. A simple linear response best described the yield response-insect density relationship when infestation occurred at early bloom. These results can be used for establishing a plant-stage sensitive economic injury level, with the caveat that yield loss potential will likely need to be adjusted upward under conditions favorable to disease being a larger component of damage.