potato late blight fact sheet washington state university

Potato late blight is easily transmitted by affected potato tubers.

Generally, late blight affects folia parts of both potato and tomato along with potato tubers and tomato fruit ( Novy et al., 2006). Late blight causes premature potato vine and tuber rots, and thereby results in poor yields. infestans, the disease can spread rapidly and defoliate entire fields within 3 weeks ( Kirk et al., 2004). When the environmental conditions are favorable for P. Late blight occurrence is favored by high humidity, dew, wet weather, and moderate temperatures (10–27☌) ( Choi, 2007). The worldwide economic damages of potatoes due to late blight are 5.0 billion dollars annually in 2004 ( International Potato Center, 2004 Latijinhouwers et al., 2004). Late blight is one of the devastating diseases affecting Solanaceous crops like potato and tomato in most potato producing parts of Korea ( Hahm et al., 1978 Park et al., 2011 Ryu et al., 2005) and worldwide. However, its susceptibility to plant diseases including late blight caused by Phytophthora infestans makes its cultivation challenging ( Chycoski and Punja, 1996 Desjardins et al., 1995 Giddings and Berg, 1919 Hahm et al., 1978 Park et al., 2011). Potato ( Solanum tuberosum L.) is one of the most important vegetable crops in Korea and worldwide. velezensis AFB2-2 strain could be considered as a promising biocontrol agent for P. The AFB2-2 strain was found to harbor the biosynthetic genes for bacillomycin D, iturin, and surfactin. The nucleotide sequences of AFB2-2 strain were searched in the NCBI GenBank Bacillus siamensis strain KCTC 13613, Bacillus velezensis strain CR-502, and Bacillus amyloliquefaciens strain DSM7 were found to have a genetic similarity of 99.7%, 99.7%, and 99.5%, respectively.

Among the three concentrations of AFB2-2, the disease incidence and severity of potato late blight at 10 7 cfu/ml was lowest at 0.07 and 6.7, respectively. Among the concentrations of AFB2-2, 10 7 cfu/ml showed the highest control value of 85.7% in the greenhouse. AFB2-2 strain inhibited the mycelial growth of seven plant pathogens by an average inhibitory zone of 10.2 mm or more. The maximum salt concentration tolerated by AFB2-2 strain is 7.5% NaCl. It can survive at 20–50☌ in tryptic soy broth. The optimal growth temperature of the strain is 37☌. It can utilize 20 types of carbon sources, like L-arabinose, and D-trehalose at 35☌. AFB2-2 strain is a gram-positive with peritrichous flagella. It is a necessary to develop an effective biocontrol agent to inactivate late blight in the field. Although late blight is an important disease in ecofriendly potato cultivation in Korea, it is highly dependent on the use of eco-friendly agricultural materials and the development of biological control technology is low.

Potato late blight fact sheet washington state university