Strawberry crinkle cytorhabdovirus (SCrVOO), Strawberry mild yellow edge virus (SMYE), Raspberry ringspot virus (RPRSVO), Tomato black ring virus (TBRV), Arabis mosaic virus (ARMV), Strawberry latent ringspot virus (SLRSVO)
The symptoms caused by viruses on strawberries can vary and are strongly dependent on the aggressiveness of the respective virus strain and the susceptibility of the strawberry variety used. Mixed infections with other viruses can increase or change the symptom expression of viral disease of strawberry. Some viruses occur latently, meaning that the viruses are present in the plant but symptoms are not yet visible (e.g. Strawberry latent ringspot virus). For other viruses (e.g. Strawberry mild yellow edge virus), symptoms only become visible when the strawberry is infected with another virus. Furthermore, the symptoms of viral diseases of strawberries also depend on the season or temperature and on the interval between infection and inspection. Therefore, an exact assignment of visually visible symptoms to a single virus is not possible. Instead, attention should be paid to general virus symptoms. In case of suspicion, laboratory testing is essential.
General virus symptoms are:
- Abnormalities of the chlorophyll apparatus, e.g. mosaics, ring spots, yellowing, vein lightening, or necroses on the leaves.
- Shape changes, e.g. rolling, curling of leaves, reduction of leaf area or tissue growths (enations - leaf-like protrusions), shoot deformations, fruit deformation or hardening
- growth inhibition, e.g. dwarfism
- Strawberry crinkle virus and Strawberry mild yellow edge virus: natural occurrence only on strawberries (Fragaria sp.)
- Raspberry ringspot virus: very large host plant range; main hosts are raspberry, strawberry, cherry, hops, grapevine and elderberry
- Tomato black ring virus: large host plant range; yield losses of economic importance on strawberry, raspberry, currant and peach
- Arabis mosaic virus: very large host plant range; main hosts: strawberry, raspberry, hops, grapevine and elderberry
- Strawberry latent ringspot virus: very large host plant circle, in fruit growing on strawberry, currant, raspberry and blackberry, elderberry, peach, plum, cherry, grapevine
Propagation and transmission
Strawberry crinkle virus and Strawberry mild yellow edge virus are transmitted by the aphid species Chaetosiphon fragaefolii occurring on strawberries.
Strawberry latent ringspot virus, Raspberry ringspot virus, Tomato black ring virus and Arabis mosaic virus are transmitted by soil nematodes of the species Longidorus sp. and Xiphinema sp.
While Strawberry latent ringspot virus and Tomato black ring virus cause only minor damage and are of secondary economic importance, infections by Raspberry ringspot virus, Arabis mosaic virus and especially Strawberry crinkle virus weaken plant development. They lead to high yield losses, especially in mixed infections, and can cause considerable economic damage to some varieties. Strawberry mild yellow edge virus causes damage only in mixed infections.
However, due to the requirements in strawberry certification and the nowadays common meristem propagation (propagation from plant cells under lower sterile conditions) in the production of elite plants, the practical importance of virus diseases in strawberries has decreased considerably in the last decades.
Prevention and control
- Purchase of recognized, certified planting material (elite plants) as starting material for propagation
- Examination of plants on arrival at the farm for latent infections
- Planting material production: examination of the soil for the virus-transmitting nematode species Longidorus sp., Xiphinema sp.
- The distance of the propagation area to strawberry plants for fruit production should be at least 50 m
- prevention of virus transmission by vector treatment (aphids) with approved plant protection products (see list of plant protection products approved in Austria)
- regular control of infestation during cultivation
Measures in case of suspicion
- sampling and sending plants with typical symptoms to a testing laboratory
- Suspension of the sale of plants from suspected plant stocks or deliveries until the laboratory results are available
- Remove and destroy diseased plants without harm to prevent further spreading
- Determine the origin of the infestation (e.g. additional purchase, ...)
- In case of positive detection of viruses transmitted by nematodes, the field should no longer be used for seedling production.
Last updated: 01.09.2023