Cultural Weed Control in Fruit
Crops
Excerpt from 2010-2011 Chapter 15, Publication 75,
Guide to Weed Control, Order
this publication
Table
of Contents
- Introduction
- Cultural Weed Control in Fruit Crops
- Perennial Weed Control
- Site Preparation
- Mulching
- Reducing Weed Pressure
- Rotating Herbicide Families
Introduction
In April of 2009, the Ministry of Environment ammended the Pesticides
Act with the Cosmetic Pesticides Ban Act, 2008 and Ontario
Regulation 63/09 . Pesticides are now classified for sale and use under
11 different classes. It should be noted that agriculture (e.g. nursery
production) is exempted. For more information on the legislation see the
Ministry of the Environment's website at www.ontario.ca/pesticideban.
Cultural Weed Control in Fruit Crops
A successful weed control program must integrate cultural and chemical
weed control practices. Growers cannot depend entirely on chemical weed
control in fruit and vine crops, since there is a limited spectrum of
herbicides registered for these crops.
Perennial Weed Control
It is important to identify and control perennial weeds in the preplanting
year. It is very difficult to control perennial weeds once a planting
is established because of crop sensitivity to some herbicides and since
it is not possible to clean cultivate in established orchards or vineyards.
The following perennial weeds present serious problems in these crops;
quackgrass, bindweed, vetch, wild grape, perennial nightshade, thistles,
ground-ivy (creeping Charlie) and burdock.
Systemic herbicides such as glyphosate (eg. ROUNDUP) or amitrole (eg.
AMITROL 240) should be applied to perennial weeds in the preplanting year.
Consult the product label and be sure to use the recommended rate for
the weed in question. Apply the herbicide at the proper stage of growth
of the weed, otherwise only temporary control will be achieved. Repeated
cultivations of some perennial weeds such as bindweed will also provide
control.
Site Preparation
A green manure crop such as perennial rye-grass or Sudan grass should
be established in the preplanting year following or in conjunction with
measures to control perennial weeds. This crop will provide competition
to reduce weed growth as well as improving the soil structure. Non-selective
herbicides can be applied before planting the green manure crop and before
plowing it under. Short residual selective herbicides such as 2,4-D may
be used with the green manure crop, but avoid using herbicides that leave
a soil residue that will carry over into the planting year. See Chapter
6, Preplant-Site Preparation Prior To Any Crop, page 81.
Mulching
A biodegradable plastic mulch could be used for weed control in the planting
strip. Mulch will also assist in weed control beneath the trees or in
the planting strip if it is applied early in the season before the weed
seeds germinate. Use mulch that is free of weed seeds and ensure that
enough nitrogen is provided for the plants. The mulch should be pulled
away from around the tree bases for winter rodent protection. Peastone
gravel is another option that can be applied around the base of the trees.
It will provide weed control, as well as, improving drainage, encouraging
deeper rooting and discouraging rodents.
Reducing Weed Pressure
Cultivation can provide weed control between the rows. Alternatively,
a vigorous sod between the rows will prevent weeds from becoming established.
It is better to seed in a fescue sod rather than rely on a natural sod
composed of weed and grass species because the weeds will seed into the
orchard or vine row.
Prevent weeds from setting seed in adjacent uncropped areas by using
cultural or chemical weed control measures. Mowing at regular intervals
will prevent many weeds from flowering. Try to control weeds that escape
before they set seed by cultural removal or chemical mowing. In some situations,
tools such as a weed whip may be of use. Mowers are available which will
cut close to the trees without injury. Mowing, however, will not eliminate
weed competition.
Rotating Herbicide Families
(See Table 4-5, Herbicide
Groupings for Ontario, page 65)
In perennial crops, rotation of herbicide families is important to minimize
the building up of seed from weed escapes, including triazine tolerant
weeds. Rotation will also help avoid an accumulation of herbicide residues
in the soil that may result in crop injury over a period of years and
may hinder replanting.
Related Links
