Interrupted Wet Period (IWP) to Forecast the Aerial Alternaria in Potato Crops of A Limia (Spain)

Abstract

Potato early blight caused by Alternaria solani generates significant economic losses in crops worldwide. Forecasting the risk of infection on crops is indispensable for the management of the fungal disease, ensuring maximum economic benefit but with minimal environmental impact. This work aimed to calculate the interrupted wet periods (IWP) according to the climate conditions of A Limia (Northwest of Spain) to optimize the prediction against early blight in potatoes. The study was performed during nine crop cycles. The relative hourly humidity and Alternaria concentration in the crop environment were taken into account. Alternaria levels were monitored by aerobiological techniques using a LANZONI VPPS-2000 volumetric trap. The relationships between weather conditions and airborne Alternaria concentration were statistically analyzed using Spearman correlations. To establish the effectiveness of wetness periods, the first important Alternaria peak was taken into account in each crop cycle (with a concentration greater than 70 spores/m 3 ). Considering the six interrupted wet periods of the system, it was possible to predict the first peak of Alternaria several days in advance (between 6 and 38 days), except in 2007 and 2018. Automated systems to predict the initiation of early blight in potato crop, such as interrupted wet periods, could be an effective basis for developing decision support systems. The incorporation of aerobiological data for the calculation of interrupted wet periods improved the results of this system.

Modification of the TOMCAST Model with Aerobiological Data for Management of Potato Early Blight

“…In Spain, increases on temperatures, shorter winters and longer, drier and hotter summers are some of the reliable effects. Thus, a longer duration and intensity of early blight attacks in potato crops for future years is expected [5,18].…”

“…Wet periods favor germination and infection of Alternaria [18,25,41,42]. The relative humidity of air is the most studied variables influencing positively in the sporulation and infection of potato early blight [5,18,25].…”

“…Wet periods favor germination and infection of Alternaria [18,25,41,42]. The relative humidity of air is the most studied variables influencing positively in the sporulation and infection of potato early blight [5,18,25]. However, some researchers concluded that leaf wetness duration together with potato variety are critical factors to forecast the risk of infection of early blight in Solanaceae [14].…”

“…In recent years, a higher incidence of early blight has been observed on potato plants in A Limia [5,18]. Several researchers have highlighted the effects of global climatic changes on agricultural pests [19][20][21], considering the temperature as the main limiting factor [14,15,22,23].…”

Changes in the Morphological Characteristics of Potato Plants Attributed to Seasonal Variability

“…The mild temperature and mean rainfall recorded in winter represent the oceanic features, while the drought periods, accompanied by a great thermal amplitude in summer correspond to the continental features of the area. In the last decade, the annual average temperature in the A Limia region (based on an analysis of data obtained from various meteorological stations in the area) has increased by approximately 1.6 • C [33,34]. This progressive increase in temperature could affects the development of potato crops.…”