Effects of aquatic herbicides on Brazilian

pepper tree (Schinus terebinthifolius).

Cody A. Lastinger and Stephen F. Enloe

University of Florida

Department of Agronomy

Center for Aquatic and Invasive Plants

Brazilian Pepper Tree

Dan Clark, USDI National Park Service, Bugwood.org

Rebekah D. Wallace, University of Georgia, Bugwood.org

Brazilian Pepper Tree

Red Mangrove Black Mangrove

White Mangrove Buttonwood Mangrove

10,000 IslandsEverglades National

Park

Objective

• To develop selective control strategies for Brazilian pepper tree growing in mangrove communities• Examine both older and more recently labeled aquatic

herbicides

• Examine the effects of aquatic herbicides on Brazilian pepper tree seedlings and young trees

Methods

• Seedlings – 1 to 2 leaf stage • Plants 3 weeks old from seed

• Foliar application

• 30 DAT evaluation • Shoot height and visual injury

• Juveniles ~40 cm tall• Plants 2 months old

• Foliar application

• 30 DAT evaluation• Shoot height and visual injury

Methods

• Well established ~75 cm plants• Plants 6 months old

• Foliar application

• 90 Day Evaluation• Shoot height and visual Injury

• Shoot biomass (10cm clip height)

• Data Analysis• Percent reduction in shoot height and aboveground

biomass compared to untreated control

• Analysis of variance in R

• Multiple comparison using Tukey’s protected LSD p=0.05

Aquatic Herbicides EvaluatedHerbicide Mode of Action Rate kg ai/ha

Glyphosate Amino Acid Inhibitors 0.55

Imazamox Amino Acid Inhibitors 0.138

Bispyribac Amino Acid Inhibitors 0.073

Penoxsulam Amino Acid Inhibitors 0.016

Imazapyr Amino Acid Inhibitors 0.18

Carfentrazone PPO Inhibitors 0.036

Flumioxazin PPO Inhibitors 0.07

triclopyr Auxin Types 0.55

2,4-D Auxin Types 0.367

Fluridone Carotenoid Biosynthesis Inhibitor 0.04

Topramezone Carotenoid Biosynthesis Inhibitor 0.064

Diquat PSI inhibitor 0.73

endothall Not Classified 2.48

Pepper tree response to herbicidesseedlings 30 DAT

Juvenile plants 30 DAT

Well established plants 90 DAT

Well established plants 90 DAT

Glyphosate Imazamox Imazapyr

Seedlings 30 DAT

Juvenile plants 30 DAT

Well established plants 90 DAT

Well established plants 90 DAT

Triclopyr 2,4-D

Fluridone

Seedlings 30 DAT

Juveniles plants 30 DAT

Well established plants 90 DAT

Well established plants 90 DAT

Diquat Flumioxazin

Mangrove sensitivity to Diquat

Conclusions to date

• Seedlings (30 DAT)• Amino acid inhibitors: Imazamox and imazapyr

most effective treatments

• Growth regulators: Triclopyr > 2,4-D

• PPO inhibitors: excellent control

• Carotenoid biosynthesis inhibitors not effective • PSI inhibitor: diquat provided excellent control

Conclusions to date

• Juveniles (30 DAT)• Amino acid inhibitors: Imazamox and imazapyr

most effective treatments

• Growth regulators: Triclopyr > 2,4-D

• PPO inhibitors: limited control

• Carotenoid biosynthesis inhibitors not effective • PSI inhibitor: diquat provided excellent control

Conclusions to date

• Well established plants• Triclopyr, imazapyr, and glyphosate provided the

most effective control

• Imazamox was the only newer herbicide to show useful activity

Next Steps

• Screen four mangrove species

• Field experiments

Questions?

clastinger@ufl.edu