EVALUATION OF GRANULAR PREEMERGENT HERBICIDES FOR LANDSCAPE WEED CONTROL
Horticulture & Turfgrass
Norman Nagata
Extension Agent (Commercial Landscape, Turfgrass & Nurseries)
CTAHR, UNIVERSITY OF HAWAII AT MANOA
KAHULUI
Abstract
EVAULATION OF GRANULAR PREEMERGENT HERBICIDES FOR LANDSCAPE WEED CONTROL\r\n\r\nNagata,* N.M.1\r\n1Extension Agent, Maui County Cooperative Extension Service, University of Hawaii at Manoa, College of Tropical Agriculture and Human Resources, Kahului, Hawaii 96732\r\n\r\n The following preemergent herbicides were evaluated for weed control: Pendulum 2G (2% pendimethalin) at 2.3 lb/1,000 ft2, Freehand 1.75G (1% pendimethalin + 0.75% dimethenamid-P) at 3.5 and 4.6 lb, Ronstar G (2% oxadiazon) at 4.6 lb, Barricade DG (0.48% prodiamine) at 7.1 lb, Snapshot 2.5TG (2% trifluralin + 0.5% isoxaben) at 4.6 lb, Amaze Grass & Weed Preventer (1% benefin + 1% oryzalin) at 4.5 lb, Preen Garden Weed Preventer Plus Fertilizer (9-17-9 + 0.74% trifluralin) at 6.3 lb, and Preen Vegetable Garden Weed Preventer (100% corn gluten meal) at 20 lb. A calcareous sandy field was prepared by Basamid fumigation and Roundup to control existing weeds and seeds. The test consisted of 6’ x 6’ plots in RCB with 4 replicates. Weed seeds and preemergent herbicides were applied to plots and irrigated daily for 25 minutes. Weed counts were taken every 2 weeks for 6 months. The following results provided beyond 3 months with greater than 90% control: garden spurge (Chamaesyce hirta) was control by Ronstar for approximately 4 months (~4m) followed by 4.6 lb Freehand (~3.5m); prostrate spurge (C. prostrata) was controlled by Barricade (~5m), Ronstar (~4m), then by 4.6 lb Freehand (~3.5m); graceful spurge (C. hypericifolia) was controlled by Barricade (>6m) and Ronstar (~4.5m); Emilia sonchifolia was controlled by Snapshot (~6m) followed by Ronstar (~5.5m); coat buttons (Tridax procumbens) were controlled by Snapshot (>6m); goosegrass (Eleusine indica) was controlled by Barricade and Ronstar (>6m), Amaze (~5.5m), 4.6 lb Freehand (~4m), followed by 3.5 lb Freehand and Pendulum (~3.5m); lovegrass (Eragrostis tenella) was controlled by Barricade and Ronstar (>6m), then by Pendulum (~3.5m). A field day was attended by 29 people (n=29), where their knowledge increased by 71.4% (n=20). Seventeen people will use this information within a year, 4 will use it sometime in the future, and 1 person was unsure. This project received a 9.6 rating on its relevancy to their work (1=not relevant, 10=extremely relevant) (n=16). Attendees were able to obtain Hawaii pesticide (n=24) and golf course superintendent (n=5) recertification credits.
Authors: Nagata, N. M.
-
Nagata, N. M. Extension Agent (Commercial Landscape, Turfgrass & Nurseries), CTAHR, University Of Hawaii At Manoa, Hawaii, 96732