Cultural Weed Control in Fruit Crops

Excerpt from 2008 Chapter 15, Publication 75, Guide to Weed Control, Order this publication

Table of Contents

1. Introduction
2. Perennial Weed Control
3. Site Preparation
4. Mulching
5. Reducing Weed Pressure
6. Rotating Herbicide Families

Introduction

A successful weed control program must integrate cultural and chemical weed control practices. Growers cannot depend entirely on chemical weed control in fruit crops, since there is a limited spectrum of herbicides registered for these crops.

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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, vineyards, berry crops and nurseries.

The following perennial weeds present serious problems in these crops; quackgrass, bindweed, vetch, wild grape, perennial nightshade, thistles, ground-ivy (creeping Charlie) and burdock. In strawberries, sheep sorrel, toadflax and milkweed also present problems.

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.

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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.

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Mulching

A biodegradable plastic mulch could be used for weed control in the planting strip. A straw 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.

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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 than to rely on a natural sod composed of weed and grass species, since the weeds will seed into the herbicide strip.

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.

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Rotating Herbicide Families

(See Table 4-5, Herbicide Groupings for Ontario)

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.

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Related Links

• Weeds in Ontario
• Apples in Ontario
• Tender Fruit in Ontario
• Grapes in Ontario
• Pesticide Application and Safety
• Pesticide Companies and Agents
• OMAFRA Sprayer Calibration Calculator
• Search the PMRA website
• OMAFRA Publication 505: Ontario Weeds
• OMAFRA Publication 75: Guide To Weed Control

   

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