STRAWBERRY PLANT PESTS AND DISEASES

Strawberry plant pests and diseases

.APHIDS

Causes: Aphids are a well known pest insect that can quickly colonise the soft tissue parts of your plant. They damage and weaken the plant by sucking the sap out of pressurised parenchyma cells found just below the leaf's surface.

Symptoms: Clusters of these small insects are readily identifiable, normally at the plants tips or on the underside of their leaves. In severe cases, the infected parts can begin to wither due to the quantity of sap being removed from that area.

Treatment: There are many chemical treatments available including a number of organic, but all of these must be applied at the first signs of infection to achieve the best effect.

For further information click onto:
Sacrificial Planting
How to Make a Natural and Organic Insecticide for Aphids
How to Make your Own Organic Pyrethrum Insecticide
Which Plants Attract Aphid Predators to the Garden?

SLUGS AND SNAILS

Causes: Slugs are the gardeners No.1 pest and fully ripe strawberries are an absolute magnet for them. The reason strawberries have the word 'straw' in their name is because not only was it used to protect the fruits from fungal rots by lifting off of damp ground but it was used to as an effective barrier against slug and snail attack.

Symptoms: After an attack by slugs and snail you would normally find characteristic slime trails around and on your plants and fruit. Also, if the ripening fruit is eaten, you will find irregular holes in it caused by their rasping toothed tongues.

Treatment: Outside of using slug pellets which can bring about its own collection of environmental problems, click onto What are the Safe Organic Alternative to Slug Pellets for a full selection of organic controls.


STRAWBERRY POWDERY MILDEW

Causes: This is a particular problem on strawberries especially during hot dry summers. Caused by the fungus Sphaerotheca macularis it can also be a problem on other soft fruit such as blackberries and raspberries.

Symptoms: Strawberry powdery mildew can be recognised by the appearance of powdery, grey-white patches appearing on the undersides of leaves. This is accompanied by reddish brown markings on the top side of the leaves which curl upwards along the markings as though suffering from drought. If the problem is not addressed the fungus can go on to infect both flowers and fruit, ruining the crop.

Treatments: It is possible to avoid these fungal attacks by planting resistant varieties such as 'Cambridge Favourite and 'Red Gauntlet and by trying to improve air circulation around your plants. However if this problem does occur remove and burn all affected plant matter, and in extreme cases you may wish to spray with a copper based fungicide.

GREY MOULD

Causes: Grey mould of strawberries is caused by the fungus Botrytis cinerea, which can infect both the flowers and the fruits. This can greatly reduce fruit yields and is considered to be one of the most damaging diseases of strawberry cultivation. Botrytis is most prevalent during prolonged cool, wet weather during bloom and near harvest.

Symptoms: Blossoms commonly turn brown and die. A soft, light brown rot may appear on any part of the berry, but generally occurs first in the area of the cap, destroying the berry within 48 hours. The infected fruit spot is at first a light brown color and somewhat soft in texture. As the entire berry becomes infected, the rotted area becomes firm and turns a darker brown color. Fruits soon "mummify" and, like the blossoms, become covered with a gray, dusty powder which are the spores of the Botrytis fungus. Berries resting on damp soil or touching infected plant parts are most commonly infected. Botrytis fungi overwinter as dark-colored, resting bodies (sclerotia) on dead tissue. In the spring during cool humid weather, spores form and spread by wind or water to wounded or extremely soft plant tissues. Infection can also occur from growth of fungal mycelium from previously infected plant parts. The fungus can survive on decaying vegetation so it can infect healthy plants throughout the growing season.

Treatments: Collecting and removing infected plant parts can slow the spread of the disease, but this needs to be done frequently, especially over the fruiting period Improve air circulation around the plants, by spacing the plants widely when planting and remove older leaves so that adequate airflow speed up the drying of vegetation. Try and only work on the plants when they are dry and avoid spring applications of nitrogen fertilizer. High nitrogen levels promote excessive leaf growth and therefore increase the available surface area prone to infection. Harvest fruit regularly while removing and disposing of any rotten or severely damaged fruit as the season progresses. Don't forget the traditional practice of applying straw under the berries to raise them off of damp soil as well as helping to improve air circulation around them.

Main image credit - Tarun.real https://creativecommons.org/licenses/by-sa/4.0/deed.en

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