This virus is a member of the genus Potyvirus in the family Potyviridae and is the most common and widespread virus infecting sweet potato, occurring in almost all countries where the crop is grown. Symptoms such as leaf distortion, chlorosis, discoloration, and stunting are the major manifestations of such infection. Through thorough examinations of Dr. Laranang and her team have found out that the symptoms expressed in infected plants suggests the possibility of other viruses simultaneously infecting sweet potatoes.
During the interview, she further explained that the variety of sweet potato that was wiped out by the virus was called “Bureau”. As such devastation, it was replaced by another variety, VSP 6 or locally-known as “Super Bureau”. With its high yield, early maturity and red skin as preferred by the traders and consumers, 90% of the farmers used this variety, particularly in Tarlac and Bataan, while the 10% of the farmers in the region prefer other varieties like Bentong, Ubi, Taiwan and Binicol.
“Super Bureau” has shown tolerance to the virus, and now, it has succumbed to the said infestations. Dr. Laranang emphasized the devastation has caused more than 50% reported losses or no yield at all.
Dr. Laranang collaborated with Dr. Erlinda A. Vasquez, Dr. Manuel K. Palomar, and Dr. Edgardo B. Barsalote of the Visayas State University in their research titled “Incidence of Sweet Potato Viruses in Central Luzon, Philippines”, using NitroCellulose Membrane – Enzyme-Linked Immunoabsorbent Serological Assay (NCM-ELISA)” and they have revealed that there were detected viruses such as Sweet potato Feathery Mottle Virus (SPFMV), Sweet potato Mild Mottle Virus (SPMMV), Sweet potato Latent Virus (SPLV), Sweet potato Chlorotic Fleck Virus (SPCFV), C-6 Virus, Sweet potato Mild Speckling Virus (SPMSV), Sweet potato Caulimo-like Virus (SPCalV), and Sweet Potato Chlorotic Stunt Virus (SPCSV) in the sweet potato farms in Central Luzon.
Six to eight viruses were found in Tarlac and three to four viruses in Bataan. Basically, all sweet potato growing areas of Tarlac are “hotspot” areas of sweet potato viruses.
Due to the widespread sweet potato viruses, the TAU Root Crops Research and Training Center (RRTC), headed by Dr. Laranang, developed the SP-CPM to address this menace. Dr. Laranang reiterated that, “a key to a successful harvest, certified and clean planting materials should be used.” She explained that they clean the potential planting materials through thermotherapy and propagate the clean planting materials in the laboratory through tissue culture of the meristem of the sweet potato. Meristem is basically the area where cells are actively dividing and has a minute chance to be infected by the virus, she added.
While the technology transfer to the farmers is still a challenge, the university has already partnered with the Mayantoc Sweet Potato Clean Planting Materials (SPCPM) Cooperative where they have served as distributors of the planting materials aside from their sweet potato developed products such as noodles and snacks. (MBagsit, CAF)