SAN DIEGO (Border Report) -- Flower shops in Tijuana expect another year of plummeting sales for marigolds, the popular Día de los Muertos flower used to decorate grave sites and altars dedicated to the dead. Sales of "cempasúchil," as the flower is called in Mexico, have been dropping for 13 consecutive years, according to flower vendors like Reyna Soto, who say sales are down by 90% since 2011. Lifelong ‘rivals’ recall love and admiration for pitching legend Fernando Valenzuela The marigolds are popular during the Day of the Dead celebrations due to their vibrant color and strong scent, which is believed to guide the spirits of the deceased back to their loved ones. "Last year we had so many flowers left over," Soto said in Spanish. "People just aren't buying them as much as they used to, they used to get five to ten bushels at one time, now they only take two, maybe three." Soto stated she and others are trying to make it enticing for customers to buy the flowers in bigger numbers. "We've tried to lower the price, make deals, but they don't sell as much as they once did," she said. "People used to take them to cemeteries in bunches, now they might take just a few of the flowers." President Biden honors Tejano legend Selena Soto fears the marigold tradition is slowly dying away, not being passed onto younger generations. "I used to order up to 300 bushels of cempasúchil from distributors during the season, now I get 20 and maybe another 20 later on." Marigolds can cross the border in small quantities, but many other items used to decorate altars for the dead cannot be brought to the U.S. from Mexico. U.S. Customs and Border Protection is advising the traveling public that certain agricultural items are prohibited from entering the U.S. because they can carry harmful pests and diseases, such as the citrus greening disease.  These Día de Los Muertos items are not allowed into US ports of entry Some fruits are also banned. “As All Souls’ Day draws near, C.B.P. agriculture specialists at ports of entry tend to see an increase in travelers bringing agricultural items from Mexico to decorate 'altares' to honor their departed loved ones, we want to remind them not to bring in prohibited citrus and floral arrangement fillers,” said Director, Field Operations Donald Kusser, Laredo Field Office. “Our CBP agriculture specialists conduct agricultural examinations every day, and their work is critical in preventing plant pests and diseases not known to exist in the U.S. from establishing themselves and inflicting ecological and economic harm on American agriculture.” According to Kusser, a common type of ornamental greenery known as murraya, or orange jasmine, is often used such altars.  Murraya is said to be a host plant for the Asian citrus psyllid, Diaphorina citri Kuwayama, an insect that can carry citrus greening disease and is therefore prohibited from entry into the U.S. Citrus fruits that are disallowed at the border include oranges, grapefruit, tangerines, sour oranges and sweet limes. Other popular fruits that are also prohibited such as guavas, mangoes, peaches and pomegranates. Visit the BorderReport.com homepage for the latest exclusive stories and breaking news about issues along the U.S.-Mexico border Failure to declare prohibited agricultural items also can result in fines. CBP says penalties for personal importations of undeclared prohibited agricultural items can run as high as $500, but up to more than $250,000 for commercial importations.