Incidence of Phytophthora infestans (Mont.) de Bary on potato and tomato in Maine, 2006–2010

Abstract

Late blight, caused by Phytophthora infestans (Mont.) de Bary, is a devastating disease which is found worldwide. In Maine, United States (US), we recorded late blight on potato and tomato during the 2006-2009 cropping seasons. From 2006 to 2008, over 90% of the diseased samples were collected in potato fields from northern and central Aroostook County in Northern Maine, US. Then, in 2009, an unprecedented influx of inoculum on infected tomato transplants shipped to retail garden centers throughout the Northeast US significantly changed the late blight infection patterns. In 2009, 43% of diseased samples obtained were from tomato, and 57% from potato, and disease was found to occur all over the state. Moran's index and spatial autocorrelation analysis of disease occurrence, geographical locations, host factors, and infection levels from previous years, were not statistically significant (p > 0.05). Therefore, random distributions of late blight incidences were recorded across locations and years. Nearest neighbor analysis revealed that mean spatial distances for late blight occurrence ranged from 1.51 to 71.4 km from 2006 to 2008, and 7.4 to 126.5 km in 2009. The frequency and locations of late blight outbreaks in 2009 were substantially greater than in 2006, 2007, and 2008, as affected by the influx of inoculum and movement of infected tomato seedlings as well as conducive environmental conditions. All were contributing factors for late blight occurrence in Maine. In 2010, few disease samples were collected, indicating that the influx of inoculum in 2009 did not persist to cause widespread disease in 2010. The reduction of inocula sources, fungicide protection of susceptible hosts, and the removal and destruction of infected tomato seedlings and potato cull piles or volunteer plants, can greatly reduce late blight occurrences and improve potato production. These actions should be considered as an integral part of late blight management programmes in regions where late blight commonly occurs.Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation for endorsement by the US Department of Agriculture or the University of Maine. USDA is an equal opportunity employer.

Survival potential of Phytophthora infestans sporangia in relation to environmental factors and late blight occurrence

“…The climatic data recorded and observed for the 2009 cropping year showed a broader distribution of RH compared to the 2005 to 2008 years, and indicated that climatic variations may occur from year to year. Variations in temperature and relative humidity values and their conduciveness for late blight development have been previously documented (Olanya et al 2015). The numerically lower solar radiation, temperatures, and relative humidity values at the potato canopy at the Presque Isle site compared to published data, suggests that conditions for pathogen survival were more conducive at Presque Isle than that recorded in the published data of Sunseri et al 2002.…”

“…The occurrence of SSP was consistent with favorable conditions for spore survival and implied that late blight outbreaks may be expected under such conditions. Previous research that assessed the incidence of late blight on potato and tomato in Maine (Olanya et al 2015), indicated that the frequencies of late blight outbreaks were substantially greater when temperatures and relative humidity were favorable. This is in agreement with the possibility that sporangia survival potential would be greater during such conditions.…”

“…The following ways are used to control pathogen inocula: through the use of certified disease-free seed tubers, host-resistance, cultural practices, and judicious use of protective chemicals, yet disease spread can still result through wind dissemination of sporangia from neighboring regions or incidental movement of infected plants. Therefore, periodic occurrence of potato late blight and other diseases have been observed in Maine production regions during the last several years (Groves 2002;Olanya et al 2009aOlanya et al , 2015. The outbreaks of late blight from 2005 to 2009 indicate disease reoccurrence over a multiyear period and potential significance to this production region ( Table 1).…”

Occurrence of different diseases of tomato under field condition in Raipur

“…Among them collar rot or Sclerotium wilt; Sclerotium rolfsii (Mahato et al 2017) [22] , damping off; Fusarium spp., Pythium spp., Rhizoctonia solani, Sclerotium rolfsii (Prasad et al 2017) [33] , early blight; Alternaria solani (Roopa, 2012) [39] , Fusarium wilt; Fusarium oxysporum f.sp. lycopersici (Manikandan and Raguchander, 2014) [23] , late blight (Olanya et al 2015) [30] , Septoria leaf spot (Parker et al 1997 andBlum, 2000) [31,11] , bacterial fruit canker; Clavibacter michiganensis subsp. michiganensis (Ftayeh et al 2010 andSharabani et al 2013) [18,41] , bacterial wilt; Ralstonia solanacearum (Ayana and Fininsa, 2016) [9] , bud blight; Groundnut bud necrosis virus (Manjunatha et al 2010) [24] , leaf curl; Tomato leaf curl virus (Shelat et al 2014 andYadav et al 2014) [42,48] , tomato mosaic; Tomato mosaic virus (Alishiri et al 2013) [4] , tomato spotted wilt; Tomato spotted wilt virus (Sevik and Arli-Sokmen, 2012) [40] and Root knot; Meloidogyne spp (Naz et al 2012) [28] are major diseases of tomato (Mahato et al 2017) [22] .…”