It causes mild foliar symptoms including smaller leaves that curl downward, giving the plant a more upright growth habit.
Plants can also be stunted, and leaves can be grey and distorted. The stems are often more branched, with the branches having sharp angles on the stem. Tubers are narrow and spindle or oblong in shape, or more rounded than expected for a particular variety, and have prominent eyebrows see below.
Tubers can also become cracked or develop knobs and swellings. PSTV can also infect tomato and nightshade. Various insects have been reported to transmit PSTV, but the most important disseminator is human movement through the field. Sanitize tools and machinery. Rogue infected plants before they can serve as a source of inoculum. PSTV causes elongation of tubers right side.
David Thurston, Cornell University. It is nonpersistently transmitted by aphids. AMV causes a distinct calico pattern yellow blotching on leaves. Some strains of the virus can cause severe stunting and stem and tuber necrosis. It is not considered an economically important virus. Aphids carry the virus in to potato crops from nearby alfalfa or clover fields. Insecticides are not effective. Avoid planting potatoes near alfalfa or clover.
Buy seed potatoes that have been certified virus-free. Saving potatoes from a field which was infected by virus will increase the number of plants serving as sources of virus in the following season. Remove "volunteer" potatoes in the spring potato plants coming up from tubers left over from the previous season , as these may be virus reservoirs. Proper composting may be effective to remove potatoes with Potyviruses , Carlaviruses , or Potexviruses , but not those with protozoan or nematode vectors.
Plant early to avoid aphid-transmitted viruses, scout for aphids regularly and apply insecticide not effective for PVY or crop oils as appropriate. Symptoms vary by time of infection, temperature, variety, and virus strain - It is not possible to tell what virus is present in potato plants by symptoms alone.
In order to choose the best management technique, get symptomatic plants tested:. Sanitize all tools, planters, and cultivators frequently, especially when moving equipment into a new area.
Avoid the spread of soil which could harbor the vectors of some potato viruses between fields. Necrotic symptoms on potato tubers of the variety Nicola caused by PVY NTN Management Since PVY is a nonpersistent virus and is transmitted quickly by aphids, the use of insecticides to control spread is generally not effective. Foliar symptoms of TRV infection and tuber symptoms of corky ringspot disease. Foliar symptoms of PSTV.
Note the small leaves and upright growth habit. AMV causes a 'calico mosaic,' or yellow blotching of leaves on potato. Rogue weeds which may serve as reservoirs of viruses. Viruses account for almost half of the pathogens involved in emerging infectious crop diseases [18]; and their spread is linked to several factors including the susceptibility of the crop variety [19].
Lack of resistance to pests and diseases is known to be one of the major problems for potato cultivation in Cameroon [20]. Faced with the non-existence of virucides, the genetic heritage of certain potato varieties confers resistance to certain viruses [21]. Varietal resistance can also be acquired artificially. This process requires the search for resistance genes and their incorporation into potato genotypes.
This is the case of the Rysto gene taken from Solanum stoloniferum which is grafted onto chromosome number 12 of the potato and which confers resistance to the different strains of Potato virus Y PVY [22].
Figure 1. Bar chart representing the proportion farmers with varieties grown in the agro-ecological zone of the western highlands of Cameroon.
According to the knowledge of viruses, This shows that very few farmers are aware of the existence of the viruses, as reported by Biao et al. Although some virus symptoms are almost identical to those of other pathogens, there are also symptoms that are easily differentiated, such as Potato leaf roll caused by Potato leaf roll virus.
However, farmers tend to confuse all the symptoms of the different viruses with those caused by other pathogens, especially fungi late blight and bacteria bacterial wilt. This lack of knowledge about viruses, combined with lack of symptom control, could thus be justified by a lack of training.
According to Schreinemachers et al. The figure shows that Thus, the level of study could not influence the knowledge of. Figure 2. Bar chart representing the proportion farmers as function of educational level. There is an urgent need for training programs to fill the lack of knowledge of farmers in various topics, in order to contribute to improvement of yield, as reported by Rahman et al. Knowledge of the mode of transmission of viruses and their life cycles is very important for disease prevention [29].
Among the 44 farmers who know about the existence of viruses, 38 However, only 5 2. It therefore appears that very few farmers know the modes of transmission of potato viruses.
Surveys have revealed that several control techniques are being adopted against insects in potato cultivation. The use of chemicals is generally the main strategy of insects control on crops [27]. According to Mondedji et al.
However, their inappropriate use causes various drawbacks, including increased insect pest and vector resistance [29] which contributes to crop devastation and virus transmission. Several reasons were given for the choice of different insect control techniques adopted by the surveyed farmers. Indeed, These results could thus justify the low proportions of intercropping and the use of plant extracts in insect control in the agro-ecological zone of the western highlands of Cameroon.
Figure 3. All the farmers surveyed use various combinations of synthetic insecticides. Among these insecticides, that with the trade name Cofresh EC It was followed by the Cicogne EC Plant species used by farmers as plant extract for insect control.
It emerges that eight 8 plant species were cited, and are among others: Chenopodium ambrosioides 3. It should be noted, however, that some farmers use neem oil Azadirachta indica bought in markets. As for intercropping, four 4 plant species were cited by the farmers surveyed.
These were Zea mays 5. A total of twelve 12 plant species, belonging to nine 9 botanical families, were cited in the field of potato protection against insects. These include the species Allium cepa , Azadirachta indica , Carica papaya and Lantana camara [30] [31].
In order to destroy insects and all potato pests, 10 4. These include: wood ash and rabbit urine. Many authors have already demonstrated the pesticidal effects of wood ash of some tree species [32]. Table 3. Summary of synthetic insecticides used by farmers surveyed. The concept of viral disease and its transmission are little known by potato farmers in the Western Highlands of Cameroon; only Insect control is essentially chemical and very few farmers use alternative methods 7.
However, Chenopodium ambrosioides has been the most cited plant species in the fight against insects as a plant extract; while Zea mays has been the most for intercropping. Therefore, it emerges from this study that knowledge of potato viruses is not linked to the level of education, age or marital status, but rather to the training undergone by farmers. Faced with these results, it is imperative to train farmers with regard to potato virus diseases and their management, in order to help to improve yields.
We are very grateful to the potato farmers in the Western Highlands of Cameroon who accept to providing information to us during data collection. The authors declare no conflicts of interest regarding the publication of this paper. Journal of Agricultural Sciences, 17, Listing of Factsheets and Information Bulletins regarding Potatoes. Choose a vegetable from the pull-down menu below to get a listing of Fact Sheets and Information Bulletins relating to that crop.
We acknowledge the use of photographs provided by Dr. Thurston, Department of Plant Pathology. Quantity discount available. Department of Agriculture, cooperating. In furtherance of acts of Congress May 8 and June 30, , and providing equal opportunities in employment and programs. Lucinda A Noble, Director. Potatoes are a vegetatively propagated crop, and many disease organisms including several viruses and a viroid are disseminated in tubers.
The important role that tubers play in virus spread is recognized by the strict requirements for foundation or certified seed production.
Seven viruses and spindle tuber viroid are recognized as important in the state from either a production or a seed certification standpoint. The viruses include potato leafroll virus, potato viruses Y, X, A, S, M, and alfalfa mosaic virus, with the first three being the most important. Major Potato Viruses Potato leafroll virus PLRV causes an important disease of potatoes affectine the auantitv and quality of production and may cause a crop to be ineligible for certification.
Diseases By Crop Fact Sheets. Photo Gallery. Diagnostic Keys. Resistant Varieties. Glossary of Plant Pathology Terms. Potato spindle tuber viroid PSTV can cause a destructive disease of potato and receives particular attention for certified seed production. Evidence suggests that chewing insects may be responsible for spread in nature, but humans and their activities serve as the principal disseminator. As the name implies, infected tubers may be spindle or oblong shaped or tend to be more rounded instead of the normal shape for a given variety Figure 7.
Prominent eyebrows are another important characteristic. The leaflets may be smaller and curve inwardly, giving a stiff upward growth habit Figure 8. Sensitive tests i. Use of these tests and the selection of certified seed are important steps in eliminating this disease from potato stocks.
Figure 6. Figure 7. Potato spindle tuber viroid PSTV -infected tubers may be spindle- or oblong-shaped or tend to be more rounded instead of the normal shape for a given variety. Figure 8.
PSTV foliar symptoms show little contrast, making this one of the more difficult diseases to diagnose. The leaflets may be smaller and curve inwardly, giving a stiff upward growth habit. Originally created by T. Zitter and D. Gallenberg for Vegetable MD Online. Updated April by:. Please, insert a valid email. Thank you, your email will be added to the mailing list once you click on the link in the confirmation email.
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