Incidence of Cranberry (Vaccinium macrocarpon Ait.) Storage Rot in Latvia

The American cranberry (Vaccinium macrocarpon Ait.) is a promising perspective and marketable crop both in Latvia and foreign markets, but an important problem is fruit rot in storage. The aim of the study was to investigate the incidence of cranberry fruit rot in storage from fruit collected in different locations in Latvia. In 2007-2011, two hundred sound berries (total 1200) were randomly collected by hand along a diagonal from six different cranberry plantations from locations all over Latvia in every year. Berries were kept in plastic polyethylene (PE-LD 04) bags for four months, refrigerated at +7 °C, 83% relative humidity. At the end of each month, berries were evaluated and rotten berries were separated from the sound ones. Over the period of 2007-2011, the optimal time for cranberry storage was two months, when losses due to fruit rot reached up to 18-21%. The incidence of storage rot at the end of storage period after four months (February) reached 50-88%. The hot and rainy summer of 2010 significantly reduced the quality of fruit in storage, and spoilage reached on the average 88% (74-100%) of berries in the plantations. The incidence of fruit rot varied among the surveyed cranberry growing sites. Storage rot is a problem in cranberry samples from all inspected plantations in Latvia and in the future, the incidence of fruit rot is expected to increase, because the greatest part of growers believe that American cranberries can grow in the same way as wild cranberries, without fertilisation and pesticide use