Agronomijas v stis - Latvijas Lauksaimniecības universitāte

Figure 12. Pycnidia of Allantophomopsiscytisporea on PDA(10x).Figure 13. Conidia of A. cytisporeaon PDA (400x).According to symptoms of cranberry rot and fungus morphological peculiarities moisture cameraand pure culture, black rot were caused by Allantophomopsis cytisporea (Fr.: Fr.) Petrak. Thecausal agent of the disease was identified based on symptoms and morphological characteristicsdescribed by Caruso F. L., 1995 and Гopлeнкo et al., 1996.DiscussionConclusions after two years (2007, 2008) investigations: in Latvia are distributed the same causalagents of cranberry diseases as in North America. According to the literature in the USA andCanada Colletotrichum acutatum, Pestalotia vaccinii, Phyllosticta vaccinii, Physalospora vaccinii,Phomopsis vaccinii and Coleophoma empetri are the most common fungi isolated from sound fruitin storage (Olatinwo et al. 2003; Oudemans et al., 1998). The fungus Fusicoccum putrefaciens wasrecovered in less than 1 % of the total isolations, it is a minor fungal pathogen in the USAaccording to investigations carried out in Michigan (1999 – 2001) and New Jersey (1994 – 1996)(Olatinwo et al. 2003; Stiles et al., 1999). Shear C. L. and Bain H. F. investigated the life cycle offungus in cranberry plantations and established that Fusicoccum putrefaciens grows well at lowtemperatures and in some seasons causes significant losses (Stiles et al. 1999). End rot was mostlyspread in Latvia (2007). The weather conditions are suitable for cranberry growing in Latvia.Upright dieback caused by Phomopsis vaccinii are widely distributed in the USA. In Latvia theincidence level of Phomopsis vaccinii is still low, but in the future it could be an economicallyimportant disease in Latvia as well.Probably causal agents with seedling material have been imported to Latvia. American cranberriesmostly propagate using uprights. It is the most common method in all the world. Next year afterover wintering fungi can develop and infect blossoms, ovaries, uprights and berries again. In thefuture a system should be developed how to control spread of cranberry diseases in plantations.Cranberry growers still do not know all specific agro technical methods of cranberry growing.Damage to cranberries can be caused also by non-parasitic diseases like drought and wrongfertilization.ConclusionUpright dieback of cranberry was caused by several agents. In the Latvian Plant ProtectionResearch Centre laboratory 6 fungi from upright dieback and 9 causal agents from fruit rot weredetected. Mainly the fruit rot symptoms were similar; therefore precise detection of the causalagent is so important.In the future causal agents Fusicoccum putrefaciens and Phomopsis vaccinii could be dangerous,because they cause upright dieback, blossom blight and fruit rot and their control could be difficultin the future.In the future research into to cranberry diseases should be continued.AcknowledgementsThis project was supported by the Ministry of Agriculture of Latvia (Contract No. 43/2007).132