Sweetpotato Virus Disease (SPVD): Distribution, Incidence, and Effect on Sweetpotato Yield in Peru

Abstract

Sweetpotato virus disease (SPVD), the most important disease affecting sweetpotato (Ipomoea batatas (L.) Lam), is caused by the synergistic interaction of the aphid-transmitted Sweetpotato feathery mottle virus (SPFMV) and whitefly-transmitted Sweetpotato chlorotic stunt virus (SPCSV). In this study, SPVD was the main disease in the Cañete Valley, the major sweetpotato-producing area in Peru. Studies on virus incidence showed that SPCSV and SPFMV were the most frequently identified viruses in Cañete Valley. Symptoms of different severity were associated with isolates of both viruses involved in the SPVD. Over 80% of plants infected with both SPFMV and SPCSV showed the symptoms (leaf reduction and deformation, vein clearing or mosaic, and stunting) typically attributed to SPVD elsewhere. SPFMV did not significantly affect the yield of the sweetpotato cultivars Jonathan and Costanero, but infection of these cultivars by SPCSV was associated with significant yield reduction. Double infection by the two viruses resulted in SPVD and greater yield reduction than for either alone. These results demonstrate that SPFMV and SPCSV interact synergistically and that the severity of SPVD symptoms also depends on the particular isolate of each virus.

Studies on propagation materials and growing conditions for sweetpotato [Ipomoea Batatas (L.) Lam] production

“…Milgram et al (1996) observed that whilst there was no significant effect of combined SPFMV and SPCSV on yield, a 30% yield reduction was observed for SPCSV in the second year. Gutierrez et al (2003) found a similar result in Peru; that SPFMV alone did not significantly affect yield, but in combination with SPCSV a significant yield reduction occurred.…”

Evaluation of Elite Sweetpotato Genotypes for Resistance to Sweetpotato Virus Disease in Southern Ethiopia.

“…Presence and absence of viruses was identified in the field using biological property related to virus interaction with its host. Accordingly, severity and incidence of disease was recorded using the leaf and plant color and size deviation from normal appearance (purple, mosaic, vein clearing) and deformation of leaf size and shape to record virus-positive samples (Gutierrez et al, 2003). Severity was recorded using a 1-5 scale; where 1 = no visible symptoms, 2 = mild symptoms (a few local lesions on a few leaves), 3 = moderate symptoms (mosaic symptoms on leaves), 4 = severe symptoms (mosaic symptoms with plant stunting) and 5 = very severe symptoms of purpling/yellowing or mosaic on leaves, severe leaf distortion, reduced leaf size and severe stunting (Mwanga et al, 2013;Njeru et al, 2004).…”

Reaction of sweet potato genotypes to sweet potato weevils (Cylas puncticollis (boheman) and Alcidodes dentipes (olivier), coleoptera: curculionidae) and viruses in Eastern Hararge, Oromiya, Ethiopia

“…These include sweet potato chlorotic stunt virus (SPCSV), sweet potato feathery mottle virus (SPFMV), sweet potato mild mottle virus (SPMMV), sweet potato chlorotic fleck virus (SPCFV), sweet potato caulimo-like virus (SPCaLV), sweet potato mild speckling virus (SPMSV), C-6 (flexious rod virus), sweet potato latent virus (SwPLV), sweet potato virus G (SPVG) and cucumber mosaic virus (CMV) with SPFMV followed by SPCSV, SPVG and SPCSV being the most prevalent (Abraham, 2010;Tewodros et al, 2011;Shiferaw et al, 2014). In East Africa, SPVD can cause yield reduction up to 98% (Gibson et al, 1997;Gutierrez et al, 2003;Ndunguru et al, 2007).…”

“…The incidences of virus diseases at both locations were evaluated using infection symptoms through visual assessment, on the leaves and other parts of the plants, from randomly selected three plants per plot. The development of purple color spots on the sample plants was used to identify virus-positive specimen (Gutierrez et al, 2003) as shown in Plate 1. The rooting characteristics of sweet potato are one of the main required parameter to evaluate the pest and drought resistance of this crop.…”