Raspberry Pests & Diseases and Best Management Practices

Wikifarmer

Editorial team

7 min read
19/12/2024
Raspberry Pests & Diseases and Best Management Practices

Protect Your Raspberry Plants: Pest and Disease Management Tips

Various pests and diseases can affect raspberry plants. To decrease the level of damage and help the plants withstand an infection, the raspberry grower needs to keep his/her plantation healthy and vigorous through balanced fertilization, irrigation, and appropriate weed management. Besides that, regular scouting of the field to identify early pest and disease problems will increase the efficiency of control measures and limit the damage caused. The importance and abundance of certain raspberry "enemies" depend on many factors and differentiate from region to region. The farmers should follow the local announcements and guidelines from the relevant authorities that can inform them concerning the population of an insect, the dangers of disease infection, and the moment and type of control measures to be applied. 

Which are the most important insects of raspberries, and how to control them

The most common insects that can attack raspberries are the Raspberry Cane Borer, Raspberry Beetle, Spotted Wing Drosophila, Aphids, and Mites. 

  • The Raspberry Cane Borer or Raspberry Horntail (Oberea bimaculata) looks like a black wasp and can cause cane dieback from the tip down. The cane dieback occurs from the middle to the end of summer. The insect cuts two rings around the stem. The rings are 1 inch (2.5 cm) apart. After that, the beetle lays eggs between the two rings, and the part over this spot wilts and dies. Once the egg hatches, the larva enters the pith and feeds there. The larva overwinters in the soil or just above the ground and emerges in the spring as an adult. The farmer can remove the affected cane part (cut 6 in or 15 cm below the tip) and destroy it. Repeat twice per week until the larvae population is under control. This measure has a higher success if applied at the end of spring. If this is not enough and the problem is extensive, then there might be a need for chemical control with registered and suitable insecticides. 
  • The Raspberry beetle (Byturus tomentosus) is a fruit worm of the family Byturidae. The Raspberry beetles overwinter in the soil and come out in spring when the temperatures are ideal. They use the flowers of Raspberries and Blackberries to lay nests for their eggs. Once the larvae hatch, they eat the stalk ends of the developing fruit until it falls. Afterward, they move into the soil, pupate, and emerge the following spring. The problem may be more extensive in autumn, with raspberry fruits ripening early. The farmer should take preventative measures in areas with a known history of insect problems even before the plant's growth period starts. In addition to using natural insect predators for control, there are also water traps on the market that use host plant odors, known as kairomones, to attract and capture these pests. If the use of insecticides is inevitable, the farmers can use organic products with pyrethrins. You should avoid spraying during the flowering period. 
  • Spotted wing drosophila (Drosophila suzukii) has been a new, important, up-and-coming pest of raspberries during the past decade in many regions of the world. Its extended list of plant hosts (berries, apples, stone fruits, etc.) makes its control quite difficult. This species can also infest unripe fruits; the most common indication of its presence is the observation of sunken and perforated fruits. The adult flies are tiny with red eyes and light brown bodies, while the males have one dark spot on each wing. The damage to the fruits is mainly caused by the females that open holes to lay their eggs. It is advised to closely monitor the insect population, starting from the end of spring. A common way to do that is by placing simple traps (plastic cups with apple cider vinegar) in the field. You can check them once a week to define the presence and population of adults. In areas with extensive problems, the raspberry farmers should harvest the fruits a bit earlier, prune the plants to promote aeration and control the weeds that can also host the insect. Some pesticides are also available (for pre- and post-harvest applications) but should be used with great caution. 
  • Aphids are very small, sap-sucking insects and members of the superfamily Aphidoidea. They puncture the plants' stems and leaves, leaving a substance behind called honeydew. The honeydew, as the name suggests, is a sticky substance that attracts other insects like ants. Aphids are also carriers of plant viruses. Other common symptoms are curled and yellow leaves. Aphids are mainly controlled by natural enemies (predators) of the insect. Some resistant raspberries are available in the market (Chemainus, Malahat, and Rudi). The use of pesticides is possible but usually not necessary since applications for other raspberry enemies like fruit worms, caterpillars, and weevils also effectively control aphids. 
  • Mites, also called spider mites, are members of the Acari family Tetranychidae and are related to spiders and ticks. They are tiny pests that usually live on the underside of the leaves and make silk webs, as their name suggests. They can be detected during the growth season (mid-spring until mid-autumn) and are usually naturally controlled by insect predators (mites and beetles). Chemical control is possible, but it is not suggested due to the ability of mites (like aphids) to develop resistance. 

Which are the Most Important Diseases of Raspberries

Some important diseases that can damage Raspberries are Anthracnose, Grey Mold (Botrytis cinerea), and Root and Crown Rot (Phytophthora sp. and Rhizoctonia sp.). 

  • Anthracnose is a disease caused by the fungus Elsinoe veneta that more commonly infects black raspberries. The symptoms, which are sunken pits and purple spots (with a light grey center), usually appear on the cane, but in extensive infection, they can also appear on the leaves and petioles. The spores of the fungus are carried by splashing rain or irrigation, infecting other plants. Most of the fungi thrive in wet soils and humidity. The control measures for the disease can also effectively control the Spur Blight. The farmer can limit the risk of infections by improving the aeration of the canopy, avoiding wetting the leaves, and removing the diseased plant parts.
  • One of the most common fruit rots is Grey Mold caused by the fungal Botrytis cinerea. Botrytis causes soft rot and mainly infects flowers and fruits. A common symptom of the disease is the water-soaked, soft rot appearance of the infected plant parts that are covered by dense grey, fuzzy fungal growth. Prolonged rainy and humid weather during the flowering stage of raspberries can increase the risk and the development of the infection. The farmer should be extra careful when harvesting because the damage to the fruits can be extended and spread during fruit storage. To limit post-harvest losses, the grower should collect healthy, firm berries and cool them immediately after harvest. Chemical control is available and suggested when favorable conditions for the fungus prevail. However, combining cultural control measures (e.g., pruning, drip irrigation instead of sprinklers, etc.) is more efficient.
  • Finally, Phytophthora root rot (Phytophthora fragariae var. rubi) is one of the Raspberries' most serious diseases worldwide. It can cause severe damage in susceptible raspberry varieties and soaked soils. The fungus causes plant thinning and the production of fewer canes each year. Primocanes and floricanes seem to develop normally, but then they wilt and die suddenly when the weather becomes warmer. Both root and crown Rot (Phytophthora sp. and Rhizoctonia sp.) cause brown or purplish lesions on new canes and the roots, resulting in yellow or dwarfed plants. It is recommended to use certified healthy plants and semi-resistant varieties, plant in raised beds (especially in poorly drained soils), and spray with suitable fungicides (only when it is absolutely necessary).
  • The most important viruses affecting the fruit and the plant of Raspberry are Bushy Dwarf and Mosaic. However, there is no treatment for viruses. If you are sure that a virus has infected your plants, you must remove them entirely from the field and dispose of them elsewhere so that the virus does not spread and contaminate the healthy plants. Since insects like aphids are the primary way the viruses can be transmitted, it would be useful to control the pest effectively. See ways to do it in the corresponding section above. 

Another serious issue that all the berries face is animals, such as birds. They may consume more than half of the berries, resulting in significant crop loss. You can avoid this by protecting the crop with nets and fences. Another thing you can do is purchase an inflamed, big predator bird balloon that will scare the birds away.

To preserve your raspberries' health, you must build an unwelcoming environment for the pests. The best practice, of course, is prevention. Grow Red Raspberries in the sun. Water regularly, but keep the soil well-drained to prevent insects from coming. Remove any dead leaves, flowers, or fruits and dispose of them in different places. Also, remove any unwanted weeds that can attract various insects. If you have done all that and your plants still suffer, you can seek advice from your local agronomist or scientist. 

However, to obtain chemical control recommendations for controlling these Raspberry pests and diseases, please consult your local licensed agronomist.

References

  1. https://extension.usu.edu/yardandgarden/research/raspberry-management-for-utah
  2. https://www2.gnb.ca/content/gnb/en/departments/10/agriculture/content/crops/small_fruits/raspberry.html
  3. https://extension.usu.edu/pests/ipm/notes_ag/fruit-rasp-horntail
  4. https://www.rhs.org.uk/biodiversity/raspberry-beetle
  5. https://extension.usu.edu/pests/ipm/notes_ag/fruit-swd
  6. http://whatcom.wsu.edu/ipm/manual/rasp/docs/raspberry_scout.pdf
  7. https://www2.gov.bc.ca/gov/content/industry/agriservice-bc/production-guides/berries/raspberries
  8. https://extension.umn.edu/plant-diseases/raspberry-cane-diseases#symptoms-of-anthracnose-1789362
  9. https://www.vgls.vic.gov.au/client/en_AU/search/asset/1281488/0
  10. https://extension.usu.edu/yardandgarden/research/raspberry-management-for-utah

Further reading

10 Health Benefits of Raspberries

Interesting facts about Raspberries

Types of berries-Superfoods

Raspberry Plant Information and Variety Selection

How to Cultivate Raspberries Commercially

Raspberry Soil Requirements, Site Preparation and Planting

How to Grow Raspberries from Seed

How to Grow Raspberries in Containers

Raspberries Propagation and Pollination

Raspberry Irrigation: Best Practices for Healthy Growth and High Yields

How to Fertilize Raspberries

How to Train and Prune Raspberries

Raspberry Yield, Harvest, and Storage

Raspberry Pests & Diseases and Best Management Practices