The Online Gardener's Handbook
Chapter 5: Fruit
Table of Contents
- Black Root Rot
- Fruit Rot or Grey Mould
- Leaf Spot
- Plant Bugs
- Red Stele
- Strawberry Clipper Weevils
- Strawberry Leafrollers
- White Grubs and Wireworms
- Learn More
In this chapter, a description of various strawberry pests will
be provided along with suggested management options. These management
options will not include the use of pesticides. Some biopesticides
and certain reduced risk pesticides are still available to the homeowner
for controlling weeds and pests in lawns and gardens. For more information,
refer to Chapter
2 of this handbook and the Ministry
of the Environment's website. For suggestions on managing specific
weeds and pests, consult local horticulturalists, Master
Gardeners or your local garden supply centre.
Black Root Rot
Black root rot is a soil borne fungal disease causing roots of
old plants to turn dark brown with no feeder roots present. The
outer root covering peels off easily. Above ground portions of the
plant will be less vigorous and may die.
Avoid heavy, poorly drained soils with high water tables to prevent
roots from becoming waterlogged or frozen. Use certified plants
to reduce the risk of introducing root diseases and viruses into
the garden. Before planting, check plants to ensure the roots are
healthy and cream coloured.
Fruit Rot or Grey Mould
Fruit rot, also called grey mould, is common during wet weather
between blossoming and harvest. Berries rot when almost ripe, although
green fruit may also be infected. Control is difficult when disease
is established; prevention is more effective.
Protect blossoms from frost injury with straw mulch. Remove infected
berries from fruit clusters when observed. If irrigation is necessary,
water thoroughly in the morning to allow time to dry before evening.
Pick all fruit at the end of harvest to reduce the incidence the
Leaf spot is a fungal disease that causes red-purple spots on leaves
of first- and second-year plants. Spots enlarge and centres become
grey. If spots are numerous, leaves may be killed and yield reduced.
Trim off diseased leaves when planting. Choose resistant varieties,
if available. Plant in well drained soil in a sunny area with good
Plant bugs pierce flower clusters and developing fruit, sucking
the sap and causing small deformed berries. For more information,
refer to the Plant Bug section in Insects
and Diseases Attacking Many Vegetables.
Red Stele is a common root rot fungal disease that causes the inner
roots to turn rusty red in April-May and September-October and have
a rat-tailed appearance. Plants are stunted because roots function
poorly and berries are small though not deformed.
Where this disease is a problem, obtain certified young plants
with cream-coloured roots every year and harvest during the following
year only. Inspect plants closely and do not plant if roots exhibit
any symptoms. Since this is primarily a disease of older plants,
remove old plantings after harvest. Improve soil drainage and avoid
soil compaction. Rotate plants among different locations, where
space permits. Plant resistant varieties, where available.
Slugs create small to moderate holes in fruit and leaves. For more
information and management options refer to the slugs sections of
and Chapter 5.
Spittlebugs are small, sap-sucking insects. In their immature stages,
they cover themselves with a frothy saliva-like protective mass.
The adults are brown and inconspicuous, and they jump easily when
disturbed. Stunting and distorting of the new growth are the most
common signs of damage. They are present in May and early June with
usually one generation per season.
Pick off and destroy. Spittlebugs can be washed off plants with
a strong jet of water.
Strawberry Clipper Weevils
Strawberry clipper weevils are destructive, 2-3 mm long, reddish-brown
beetles with long snouts. Adult weevils poke holes and lay eggs
in strawberry buds and partially cut the stems below the buds, causing
them to wilt and drop off or to hang by a thread.
Remove and destroy any fallen stems, or those that are hanging
by a thread, as these may contain weevil eggs.
Strawberry leafrollers are small, greenish or bronze 1.25 cm long
caterpillars that fold or roll leaflets with fine silken threads.
Overwintering as pupae, small greyish or brown moths emerge in mid-to-late
May to lay eggs on the undersurface of the leaves. The larvae migrate
to the upper leaf surface when half-grown, roll the leaves for protection
and continue feeding. A second generation occurs in mid-August.
If infection is minor, remove affected leaves and destroy. Natural
enemies are often present and help keep populations in check.
White Grubs and Wireworms
Wireworms and grubs may cause extensive damage to new strawberry
plantings as the larvae feed on the roots. Usually plants collapse
during the fruit-sizing period. They are often present in new gardens
when sod is converted to garden. For more information refer to the
Soil Pests section of Chapter
For management options, refer to the White Grubs section of Chapter