Timing of Cotton Fleahopper Herbivory and Cotton's Compensatory Response

One defense strategy plants utilize against herbivory is tolerance.  When plants tolerate herbivores, yield is unaffected because they alter their growth and development patterns to compensate for damage.   In some cases, this response is exaggerated and plants “overcompensate” for herbivory.  Thus, yield can be directly improved by herbivory.  Overall, it is important to consider the factors that facilitate compensatory or overcompensatory responses of crops in order to improve the management of pests.  In previous studies, Upland cotton has been found to tolerate early season herbivory by thrips and aphids. In this study we set out to determine if the timing of herbivory affects cotton’s ability to tolerate feeding by a key pest, the cotton fleahopper, Pseudatomoscelis seriatus (Hemiptera: Miridae). We used cages to manipulate fleahopper presence on cotton terminals during early weeks of square production (weeks 1 through 4).  We found evidence for compensation in overall lint yield in addition to a trend for fleahopper infestation to increase lint yield by 5-28% during the first three weeks of squaring.  In contrast, lint yield was decreased by 20% following infestation in the 4^th week of squaring.  Lint yield from the 1^st and 2^nd fruiting positions was invariable.  However, fleahopper infestation during the 1^st -3^rd weeks of squaring  increased lint production by 9-34%,  at  the 3^rd fruiting position, more lateral positions, as well as on the vegetative branches.  Thus, cotton likely compensated for early season fleahopper herbivory by producing additional lint at the lateral and vegetative fruiting positions.  Timing of fleahopper herbivory did not affect any fiber quality, but fleahopper herbivory increased micronaire.  Overall, this study found that cotton can compensate for fleahopper herbivory during the early weeks of squaring and performance may be improved by fleahopper presence.