Date of Graduation

12-2015

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Entomology (PhD)

Degree Level

Graduate

Department

Entomology

Advisor

Donn T. Johnson

Committee Member

Elena Garcia

Second Committee Member

Russell Mizell

Third Committee Member

Robert Wiedenmann

Fourth Committee Member

Fred M. Stephen

Abstract

An effective management program for stink bugs (SBs) in pecan groves requires knowledge of: stages of the pecans susceptible to SB damage; strata of the tree with SB damaged nuts; a practical SB monitoring method; and, effects of landscapes contributing SBs into pecan groves.

Stink bugs produced feeding punctures in pecan shucks at all phenological stages. Pecans punctured before the dough stage drop from the tree. Kernel damage occurs in the pecans’ dough stage, whereas mature pecans are not damaged.

The pecans collected from the whole tree using the tree shaker had significantly less punctures than the pecans collected from lower limbs. Stink bug feeding damage occurred more in the lower pecan canopy than the middle or upper canopy. Pecans collected in late-September near harvest had significantly more SB punctures and damage in the lower strata of the pecan trees than the middle or the upper strata.

The SB counts were compared from four SB monitoring methods (baited yellow pyramid traps, UV-light traps, visual surveys and canopy knock-down sprays). The most practical method for pecan growers was the baited yellow pyramid trap.

Yellow pyramid traps baited with Euschistus (Hemiptera: Pentatomidae) aggregation pheromone were used to monitor movement of SBs from adjacent landscapes to pecan groves. SB trap counts were compared to percentages of SB punctured or damaged pecans. The grove center acted as a refuge for SBs. The forest tree line and soybean landscape contributed more SBs to a pecan grove than other landscapes. The number of SBs or percentages of SB punctured nuts did not equate to percentages of SB damaged nuts. SB damaged nuts remained relatively low until the water stage. I suggested using baited yellow pyramid traps for making SB pest management decisions during susceptible water through dough pecan nut stages.

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