In This Section

Topics

Major And Minor Pests Of Strawberry:Part I Of 2 Parts

Factsheet - ISSN 1198-712X - Copyright Queen's Printer for Ontario
Agdex#: 232/600
Publication Date: September 1992
Order#: 92-137
Last Reviewed: 08/02
History:
Written by: Gerald M Walker - Pest Management Advisor/OMAF

Table of Contents:

  1. Introduction
  2. Using The Factsheet
  3. Control

Introduction

The purpose of this Factsheet is to present information which enables the grower to assess the need for control of strawberry pests in bearing years. Proper recognition of pest problems is important to minimize damage to the strawberry crop. The pest complex that attacks strawberry will vary from year to year and from field to field. The pest complex may be divided into major and minor pests. Major pests are usually present each year and if not controlled may cause substantial damage. Minor pests tend to be sporadic, restricted in location, or only cause a minor amount of damage. Sporadic may mean:

    1. the pest population levels vary depending on weather conditions that are favorable to its development (e.g., Powdery mildew);
    2. the pest may be restricted to a specific geographical area of the province (e.g., European chafer Niagara Peninsula and northern shore of Lake Erie);
    3. the pest may be very localized and found in certain fields or varieties (e.g., potato leafhoppers are attracted to the cultivars Governor Simcoe and Settler).

There are instances, where a minor pest can cause a substantial amount of damage. An example of this is leather rot (Phytopthora) which is caused by a soilborne fungus. When insufficient straw is used the fungus may be splashed onto the fruit by rain and can cause up to 50% crop loss. To control some major pests, for example, strawberry clipper weevil, it is useful to monitor the field to allow the most effective timing of an insecticide. In certain years monitoring may also reduce the number of sprays required to provide good pest control.

| Top of Page |

Using The Factsheet

The major pests are identified in the Quick Decision Chart (Table 1) while the minor pests are listed in Table 2. The quick decision chart is set up by listing the pest first, followed by the crop phenology (growth stage of plant) when the pest is present. The table can be used by knowing what pest is present in the field, or by first identifying the phenological stage of the crop. For example, during bloom when looking at the phenology section, the chart shows Tarnished Plant Bug, Botrytis Fruit Rot and Strawberry Clipper Weevil may be present then. The other sections give information on how to monitor, action thresholds and time of pesticide application, which materials may be used for control, recommended pesticide rates, warnings, other pests that may be affected, and cultural controls.

An action threshold is considered to have been reached when the number of pests or amount of injury reaches a level that could result in a direct crop loss and/or increases production costs or market loss greater than the cost of control. The warnings column provides tips on resistance management, timing restrictions of products, etc. The "Other Pests Affected" column indicates which other pests may be totally or partially controlled by the products recommended for the control of the pests specified in the "Pest and Phenology" column. For more detailed information on a specific pest it may be useful to consult other Factsheets in the strawberry series.

For problems that do not appear to be caused by major pests, consult the minor pests table (Table 2). This table lists both diseases and insects. For diseases it lists the symptoms, favorable conditions for their development, and control measures. For insects it lists damage, favorable conditions and control measures. To identify pest insects or diseases it may also be useful to consult Part 2 of this Factsheet, which provides illustrations of various pests and the type of damage incurred. When there is a problem that the Factsheet does not identify, consult the pest management advisor in your region.

| Top of Page |

Control

Good Management involves both cultural and chemical controls. Monitoring fields allows more effective timing of chemical controls because problems are only treated when necessary. When using chemical controls remember to check for the most up to date products available by consulting OMAF Publication 360 Fruit Production Recommendations. Also refer to Publication 360 for important cultural techniques, such as renovating after harvest, and applying sufficient straw which may suppress pest populations and result in reduced dependency on chemical controls. For situations that are not included in this Factsheet or Publication 360, consult the pest management advisor in your region.

Monitoring Tools
    • Hand lens
    • Shadow pan for tarnished plant bug (TPB) monitoring
    • Frame 60 cm by 30 cm (2 ft by 1 ft) for clipper weevil monitoring.
    • Threshold levels for TPB and clipper weevil
Other OMAF Factsheets Publications On Strawberry Pests
    • A Guide to Quick Identification and Decision-Making for Major And Minor Pest of Strawberry: Part 2 of 2 parts, Agdex 232
    • Botrytis Fruit Rot of Strawberry, Agdex 232
    • Tarnished Plant Bug: A Major Pest of Strawberry, Agdex 232
    • Strawberry Clipper Weevil: A Major Pest of Strawberry, Agdex 232
    • The Strawberry in Ontario, Publication 513
Other Information Sources
    • Small Fruit Crops IPM series, Cornell Cooperative Extension 1988.
    • Compendium of Strawberry Diseases, Ed. J.L. Mass, American Phytopathological Society. 1984.
    • Virus Diseases of Small Fruits. Agriculture Handbook 631 USDA. 1987.
    • Virus Diseases of Small Fruits and Grapevines. University of California. 1970.
    • Strawberry Deficiency Symptoms: A visual and Plant Disease Guide to Fertilization. University of California, Bulletin #1917, 1980.
    • Small Fruit Crop Management. Ed. Galletta and Himelrick. 1990.
    • Strawberry Pest Identification. New Brunswick. Agdex 232/600
    • The Strawberry into the 21st Century. Ed. Dale and Luby, 1991

| Top of Page |

Table 1. Quick Decision Chart Of Major Pests

Read the pesticide label and follow all safety precautions. Read cultural details on preferred timing and practice.

Pest and Phenology

Monitoring Procedure

Action Threshold and Time of Application

Effective Materials
(Days to Harvest)

Strawberry Clipper Weevil
As flower buds extend from the crown

Check a 0.18 m2
(2 ft2) area at 5 locations per field for clipped buds. Monitor near weedy or wooded borders.

An average of 1.3 clipped buds per 0.18 m2 (2 ft2)

  1. Furadan 480 F (X)a
  2. Cymbush 250 EC (7 days) or Ripcord 400 EC (7 days)

Tarnished Plant Bug From 1st bloom until preharvest

Tapping of fruit clusters into a shallow pan. 20-50 clusters are tapped see sequential sampling method in TPB Factsheet.

When 2.25 nymphs/15 flower clusters is reached or sequential sampling equivalent

*For 1st bloom

  1. Cygon 480 E (X)a
  2. Cymbush 250 EC (7 days) or Ripeord 400 EC (7 days)
  3. Thiodan 50% WP (7 days)

*After 1st bloom

  1. Cymbush 250 EC (7 days) or Ripcord 400 EC (7 days)
  2. Thiodan 50% WP (7 days)

Botrytis Fruit Rot From when flower buds are visible in the crown to pre-harvest

Monitor weather. Infection is dependent on temperature and. rainfall.

Apply before rainfall predicted

*Up to 1st bloom

  1. Captan 50% WP (2 days) or Captan 80% WP (2 days)
  2. Phaltan 50% WP (2 days)
  3. Dyrene 50% WP (5 days)

*After 1st bloom

  1. Rovral 50% WP (2 days)
  2. Dyrene 50% WP (5 days)
  3. Phaltan 50% WP day)
  4. Captan 50% WP (2 days) or
    Captan 80% WP (2 days)

*Preharvest

  1. Rovral 50% WP (2 days)
  2. Phaltan 50% WP (l day)
  3. Captan 50% WP (2 days) or
    Captan 80% WP (2 days)

Leaf Blight

Leaf Scorch

Leaf Spot

When flower buds are visible in the crown

and

Postharvest 4 weeks after renovation to early October

Observe for lesions on leaves.

Treat cultivars, such as Bounty, Kent, Veestar, Mic Mac, Tristar and Tribute

*Prebloom

*Postharvest

  1. Bordeaux
  2. Captan 50% WP (2 days) or
    Captan 80% WP (2 days)
  3. Cyprex 65% WP (7 days) or
    Equal 65% WP (7 days)

a-(X) means there is no tolerance for the pesticide on the fruit.

Amount per hectares

Warnings

Other Pests Affected

Cultural Controls

1.1 L

280 mL

175 mL

Do not use Furadan later than bloom; toxic to pollinators and beneficials.

  1. Root weevils
  2. see above
  • Site selection
  • Isolation
  • Weed control
  • Renovation

2.75 L

280 mL

175 mL

2.25 kg

280 mL

175 mL

2.25 kg

Do not spray when beese are working. Repeated use of Cymbush, Ripocord is discouraged.

  1. Slugs
  2. Clipper Weevil, Spittlebug and Slugs
  3. Slugs and spittlebug
  • Weed control

6.75 kg

4.25 kg

2.25 kg

3.25 kg

2.0 kg

3.25 kg

2.25 kg

6.75 kg

4.25 kg

2.0 kg

2.25 kg

6.75 kg

4.25 kg

Dyrene may cause foliar injury if applied during a frost period.

 

 

Do not use Roral in Consecutive sprays or more than 2 times per season.

Captan and Phaltan provide some protection against Leather Rot.

Captan also suppresses leaf scorch and leaf spot.

  • Site selection
  • Cultivar selection
  • Weed control
  • Irrigation scheduling
  • Harrowing rows
  • Fertilization

10-10-2000 L

6.75 kg

4.25 kg

1.75 kg

1.75 kg

Cyprex, Equal may injure plant in cold weather. Alternate between products to reduce resistance development.

 
  • Site selection
  • Cultivar selection

| Top of Page |

Table 2. Minor Pests of Strawberries

Pest

Symptom or Damage

Favorable Conditions

Control Measures

Leather Rot (Phytophthora cactorum)

Infected fruit has a tough area that is discolored: in immature fruit area is brown; in ripe fruit area is purplish.

Cool, wet weather conditions plus exposed soil. Optimum temperature 21°C

Sufficient straw to cover soil. Captan and phaltan provide some control, although not registered specifically for this disease.

Powdery Mildew (Sphaerotheca Macularis sp. Fragariae)

Monitor July-September. Leaf edges roll upward. White patches of mycelium are present on lower leaf surface which later becomes purple to reddish blotches. Monitor indicator varieties such as V. series (eg. Veestar and Vantage, Governor Simcoe & Settler).

High relative humidity with no rain and temperatures between 15-27°C favor production of spores and spread of the disease.

Select cultivars that are resistant or at least not susceptible to powdery mildew. Renovate old planting as soon after harvest as possible. If present apply Benlate post renovation.

Red Stele (Phytophthora fragariae)

Stunted plants with "rattailed" roots (few adventitious roots) found in poor drained sections of field in a circular pattern. Diagnostic feature of red stele or centre of root only present when soil is cool: April-Ma and September-October.

Cool, moist soil conditions. Poor drainage and compacted soils.

Improve drainage, avoid soil compaction. If present apply Ridomil. Purchase certified nursery stock grown under guidelines of Ontario Superior Plant Propagation or similar certified programs.

Black Root Rot (a disease complex not caused by a single organism)

Roots have a dark brown or black appearance with feeder roots absent or dead. Outer root covering peals back easily.

Factors stressing the plant such as freezing and waterlogging. Mostly associated with heavy soil types.

Avoid heavy, poorly drained soils with high water tables. Crop rotation, mulch plants, subsoil tillage. Irrigate with a maximum of 1½ inches of water per time.

Spittle Bug (Philaenus spumarius)

Stunted and distorted plants with small berries. Nymphs are found in a white spit-like froth on plants.

Weedy areas with broadleaf or grasses favor high populations.

Sprays for plant bug provide control. Usually not an economic pest.

Slug (several species)

Small to moderate holes in fruit. Slime-glistening trail left on fruit and leaves. Slugs are slimy tear-drop shaped and legless

Damp rainy weather and use of mulches.

Check labels of products registered for use on strawberry to see which can be used legally. Most insecticides used to control "major pests" have some activity. Slug bait.

Root Weevil (several species)

Larvae feed on roots. Confined circular area of stunted and dead plants. Plants often collapse during fruit sizing period. Damaging insect stage is a small white grub lacking legs.

Repeated strawberry plantings in the same field may allow an increase in population.

Usually not an economic problem. Sprays for clipper provide some control. Summer fallowing.

White Grub (several species)

Larvae feed on roots. Confined circular area of stunted and dead plants. Plants often collapse during fruit sizing period. Monitor turf areas for presence. Damaging insect stage is a large C-shaped grub with brownish head and six spiny legs.

Planting strawberry after pasture or grass sod or plant near to turf.

If present, treat turf with chloropyrifos. Crop rotation. Site selection.

Potato Leafhopper (Empoasca fabac)

Reduce plant growth and runner production. Leaves bend upwards at right angles to the midveins. Yellowing of leaf edge progressing to midvein. Around post-renovation (July and August) monitor indicator varieties such as Settler and Governor Simcoe. Wedge shaped. Adults are bright green 3.2 mm in length. Nymphs are smaller and a lighter green. Hop or fly when disturbed.

Populations are highly variable, since the insects do not overwinter in Ontario and must immigrate from the USA each season. They often establish first in alfalfa hay fields and later disperse.

Insecticides.

Two-Spotted Spider Mite (Tetranychus urticae)

Brownish dry areas on underside of leaves and bronzing of leaves, reducing photosynthetic activity of leaf. Mites are less than 0.5 mm with two spots on oval body, eight legs. Webbing on underside of leaf.

Repeated use of pyrethroid insecticides. Hot, dry weather.

Found in less than 5% of Ontario plantings. Miticides. Weed control. Summer fallowing.

Cyclamen Mite (Steneotarsonemus pallidus)

Retarded, distorted, twisted growth of plant, stems do not elongate. Adult mites are pinkish orange and microscopic (25-40x to see). They cannot be seen with a hand lens. Eggs often appear as a white mass on midvein on folded leaves.

Hot, dry weather. Are easily transferred from infested plantings on implements, clothes and other materials.

Thiodan applied as a drench over the plant row. Isolate new plantings from older infested plantings. Purchase certified nursery stock grown under guidelines of Ontario Superior Plant Propagation or similar certified programs.

Paul Cermak, Pest Management Assistant, Plant Industry Branch, assisted in the preparation of this Factsheet.


| Top of Page |

For more information:
Toll Free: 1-877-424-1300
Local: (519) 826-4047
E-mail: ag.info.omafra@ontario.ca