Raspberry pests: spider mites & other raspberry bugs

Even though raspberry plants are strong and vigorous, they can still succumb to pests and diseases. Learn how to recognise the most common raspberry pest and how to control them.

With its delicious red berries, it is no wonder that raspberries (Rubus idaeus) are one of the most popular summer fruits. However, raspberry pests and diseases can not only affect the harvest but the entire plant. Read on to discover what pests to look out for and what to do if identified.

Common raspberry pests

Raspberries generally grow pest free. However, there are a few pests that can affect raspberry plants and their fruits. Here are the most common raspberry pests to look out for in your garden:

• Aphids (Aphidoidea)
• Grey squirrel (Sciurus carolinensis)
• Raspberry leaf and bud mite (Phyllocoptes gracilis)
• Raspberry beetle (Byturus tomentosus)
• Spider mites (Tetranychidae)

Aphids (Aphidoidea)

Some species of aphids like to feed on blackberries and raspberries. Sucking the sap from the foliage, aphids can lead to curled or distorted leaves. Small numbers do not generally cause much damage. However, heavier infestations may weaken plants and reduce yields. Unfortunately, raspberry aphids are often the cause of disease transmission.

The two types of aphids you are most likely to see are the large European raspberry aphid (Amphorophora idaei) and the small European raspberry aphid (Aphis idaei). Measuring 4mm and 2mm long respectively, they are both light green-yellow in colour. Smaller numbers of aphids can be tolerated or managed through squishing by hand. You can also encourage their natural predators, such as ladybirds (Coccinellidae) and parasitic wasps (Aphidiinae), into the garden.

For larger raspberry aphid infestations, control measures include spraying with natural pyrethrum, plant invigorator or as a last resort, synthetic insecticides.

Grey squirrel (Sciurus carolinensis)

Although adored by some, the grey squirrel (Sciurus carolinensis) can also be a serious garden pest. Known for damaging trees and blossom buds, the grey squirrel is also fond of eating soft fruit and nuts. Grey squirrels may leave your previous raspberry crop alone if other food sources are available. However, whether you plant raspberries directly in the ground or grow raspberries in pots, the only way to stop grey squirrels from reaching your raspberry harvest is by netting them or growing raspberries within a fruit cage.

 Raspberry leaf and bud mite (Phyllocoptes gracilis)

A type of sap-sucking gall mite, the raspberry leaf and bud mite feeds on the underneath of soft leafy growth. Symptoms of raspberry leaf and bud mites include yellow patches on the leaves, which can be mistaken for viruses, and distorted foliage. In severe cases, the buds and subsequent harvest can be affected. Being microscopic, the raspberry leaf and bud mite is not visible to the naked eye. However, you can confirm their presence by the galls that develop on the leaves.

Smaller infestations can be tolerated as fruiting may not be affected. If you identify large infestations, you can remove the infected plants and replace them with raspberry varieties that are less susceptible to raspberry leaf and bud mite. No chemical controls are currently available for domestic use.

Raspberry beetle (Byturus tomentosus)

The raspberry beetle is a serious pest of not only raspberries but blackberries (Rubus fruticosus) and loganberries (Rubus × loganobaccus) as well. Generally affecting the fruits in early summer, the adult beetles damage the raspberry buds. Furthermore, from early to mid-summer, they then lay eggs on the flowers, which develop into larvae that eat the tops of the berries and cores. You can identify the raspberry beetle by its pale brown colour and the fact that it grows to no more than 4mm in length.

Autumn-fruiting raspberries are generally not affected by the raspberry beetle, especially those that ripen after August. For summer-fruiting varieties, non-chemical controls include tolerating small numbers and using raspberry beetle traps. If the traps contain large numbers, you may want to apply a systemic pesticide suitable for edible crops.

Spider mite (Tetranychidae)

Although usually a glasshouse pest, the spider mite can also affect outdoor-grown soft fruits including raspberries. Generally affecting raspberry plants in late summer, large infestations can lead to the foliage turning green-white, premature leaf drop and a reduced harvest. You can identify raspberry spider mites by their 1mm yellow-green spider-like appearance that changes to orange or red later in the autumn. In severe cases, you can observe their fine webbing spun between the foliage.

You can control raspberry spider mites by introducing a predatory mite (Phytoseiulus persimilis) as soon as you identify them. Further controls in the fight against spider mites include applying organic sprays that contain natural pyrethrum and plant invigorators.

Along with pests, raspberries can be affected by fungal and viral diseases. You can learn more about raspberry diseases in our separate article.