How to manage field bindweed in Christmas tree production

How to manage field bindweed in Christmas tree production – Part 2

Debalina Saha<sahadeb2@msu.edu>, Michigan State University Extension, Department of Horticulture - May 06, 2020

Learn the non-chemical and chemical methods to control field bindweed (Convolvulus arvensis).

Trumpet-shaped flowers of field bindweed. Photo by MSU Plant & Pest Diagnostics.

Field bindweed (Convolvulus arvensis) is one of the major problematic weed species in Michigan Christmas tree production. It can be extremely difficult to manage because this weed species can bind and grow on tree branches, and herbicide applications may not be possible due to potential injury to Christmas trees. In addition to that, the seeds of field bindweed can remain viable for up to 50 years, and the extensive root system can reach to a depth of 30 feet in the soil. In the second part of this article series, I will discuss the possible management strategies to control this weed species in Christmas tree production systems.

Non-chemical control

Prevention practices must be undertaken, which can include removal of any seedlings before they become mature and establish as perennial plants and prevent any plants from producing seeds. If topsoil is introduced to a site, it should be clean and free of roots, rhizomes, seeds and other bindweed propagules, according to Integrated Pest Management for Home Gardeners and Landscape Professionals, 2011. Regular scouting for this weed needs to be done in fields and immediate hand removal is encouraged, as later mowing in between the Christmas tree rows can spread the seeds and rhizomes easily.

Chemical control

Preemergence herbicides

Not many preemergence herbicides have shown good control over field bindweed in established Christmas trees. Isoxaben (Gallery 75 DF), simazine (Princep 4L) and flumioxazin (Sureguard 51WDG) have shown fair control. However, the application timing of these preemergence herbicides need to be checked to avoid potential phytotoxicity to Christmas trees. Preemergence herbicides that have shown some control over field bindweed and can be used in established Christmas trees have been listed in Table 1.

*Table 1. Preemergence herbicides that have shown some control of field bindweed (Convolvulus arvensis* L.) and are labeled for use in established Christmas tree production.**
Common name	Mechanism of action WSSA and (HRAC) group	Trade name	Amount of product (active ingredient) per acre	Response to herbicide¹	Tree species on label	Time of herbicide application	Notes and limitations
isoxaben	Cellulose synthesis inhibitor 21(L)	Gallery 75 DF	0.67-1.33 lb/acre (0.5-1 lb ai/acre)	F	Pine (Scotch, White) Spruce (Blue, White) True fir (Balsam, White)	Apply in the spring before annual weeds germinate.	Apply to trees established in the field after soil is settled around the plants. May be applied over the top of trees or as a directed spray.
simazine	Photosystem II inhibitor 5(C1)	Princep 4L	2-4 qt/acre (2-4 lb ai/acre)	F	Douglas-fir Pine (Austrian, Scotch) Spruce (Blue, Norway, White) True fir (Balsam, Fraser, White)	Apply to dormant trees more than two years old.
flumioxazin	PPO inhibitor 14(E)	Sureguard 51 WDG	8-12 oz (0.255-0.383 lb ai/acre)	F	Douglas-fir Pine (Austrian, Scotch, White) Spruce (Blue, Norway) True fir (Fraser, Grand, Noble, White)	Apply in the spring before bud break, or later in the season after new growth has hardened.	Apply over the top of trees before bud break. Sureguard may cause light needle burn. Do not use Sureguard on Christmas tree seedlings less than 1 year after emergence. Do not tank mix with an EC formulation of any other pesticide to avoid needle burn.
hexazinone	Photosystem II inhibitor 5(C1)	Velpar 2L	2-4 qt/acre (1-2 lb ai/acre)	F	Pine (Austrian, Scotch) Spruce (Sitka) True fir (Fraser, Grand, Noble)	Apply broadcast before budbreak in the spring or as a directed spray after budbreak.	Apply on soil with more than 1% organic matter and less than 85% sand. Apply only once per year.
hexazinone + sulfometuron	PSII inhibitor + ALS inhibitor 5(C1) 2(B)	Westar 75 DG	6-8 oz/acre (0.281-0.375 lb ai/acre)	F	Douglas-fir Pine (Scotch, White) Spruce (Blue) True fir (Fraser)	Apply to dormant trees before budbreak in spring. Use on trees which have been established in the field for at least 1 year and are at least 4 years old.	Apply with a ground boom sprayer. Do not apply within 14 days before or after an organophosphate insecticide. Westar may stunt young trees and may cause shoot injury if applied during drought or on stressed trees. Use low rate on a small area to gain experience with Westar.
¹E = Excellent, G = Good, F = Fair, P = Poor, N = No Control

Postemergence herbicides

Postemergence herbicides that have shown good control over field bindweed includes 2,4-D (Defy amine 4) and triclopyr (Garlon 3A). Some fair control of field bindweed has been observed with clopyralid (Stinger 3L) in established Christmas tree production system. Again, be careful with the application timings of these postemergence herbicides to avoid potential injury to Christmas trees. Postemergence herbicides that can control field bindweed and can be used in established Christmas trees have been listed in Table 2.

*Table 2. Postemergence herbicides that can control field bindweed (Convolvulus arvensis* L.) and are labeled for use in established Christmas tree production.**
Common name	Mechanism of action (WSSA and HRAC group)	Trade name	Amount of product (active ingredient) per acre	Response to herbicide¹	Tree species on label	Time of herbicide application	Notes and limitations
2,4-D-dimethylamine salt	Synthetic auxin 4(O)	Defy Amine 4	1-4 qts/acre (0.95 – 3.8 lb ai/acre)	G	All conifer species	Apply before budbreak in spring or in late summer after new growth has hardened.	Avoid spraying tree foliage. Do not apply to diseased or stressed seedlings. May be applied in late summer after new conifer growth has hardened to control woody plants. Avoid spraying tree foliage. May cause injury to Pinus species if applied as a broadcast spray.
triclopyr	Synthetic auxin 4(O)	Garlon 3A	2-5 pt/acre (0.75-1.75 lb ai/acre)	G	All conifer species; Spruce (Blue) True fir (Balsam, Fraser) Douglas-fir and White pine may be sensitive to triclopyr.	Apply Garlon in late summer or early fall after conifer terminal growth has hardened and weeds and woody plants are still growing.	Apply to Christmas trees established in the field for at least 1 year. Spray towards the base of the trees. Do not apply to newly seeded grass alleys or to legume cover crops
clopyralid	Synthetic auxin 4(O)	Stinger 3L	4-10 fl oz/acre (0.09-0.23 lb ai/acre)	F	Douglas-fir Pine (White) Spruce (Blue) True fir (Balsam, Fraser, Grand, Noble)	Apply when susceptible weeds are at 3-5 leaf stage.	Do not exceed 8 fl oz/acre on blue spruce. Do not add an adjuvant or surfactant. Do not apply with air blast sprayers. May be applied over the top of trees at any stage.
¹E = Excellent, G = Good, F = Fair, P = Poor, N = No Control

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