Development and testing of a weather-based model to determine potential yield losses caused by potato late blight and optimize fungicide application

Filippov Alexey Konstantinovich ,Olga Iakusheva ,A E Rogozhin ,Valentina N Demidova ,Maria Kuznetsova ,Natalia Statsyuk

doi:10.15302/j-fase-2018239

Abstract

Late blight is one of the most important potato diseases. To minimize yield losses, various protective measures are used including fungicide application. Active use of fungicides results in a contamination of the environment. Therefore, crop protection strategies optimizing the number of treatments are of great interest. Using information about late blight development in an experimental potato field recorded over 30 seasons, a simulator to forecast yield losses caused by the disease was developed based on the number of 5-d periods favorable for reinfection of plants during a vegetation season. The simulator was successfully verified using independent data on the disease development from nine unprotected potato fields in the Netherlands and Germany. The average difference between the calculated and real yield losses did not exceed 5%. Using the simulator and weather data for a period of 2007–2017, yield losses were calculated for several areas of the Bryansk, Tambov, and Orenburg Regions of Russia. The results revealed differences in disease development between these regions and may be used to develop recommendations for a frequency of fungicide applications according to the regional risk of epidemics, leading to a significant reduction in fungicide use.

Highlights

Potato is included in the list of socially important products providing food security in Russia
Yield losses caused by the disease ranged from 1% (1972, 1997 and 2010) to 66% (2013)
For the 15 seasons (2002–2017), this value increased to 33.6%, which may be due to the increased frequency of rainy days observed in recent years in the Moscow Region and by a colonization of the field by more aggressive P. infestans populations

Summary

Introduction

Potato is included in the list of socially important products providing food security in Russia. Today the use of chemical fungicides is the most important component of an integrated protection of potatoes from late blight. Chemical protection of crops sometimes loses its effectiveness due to emergence of new pathogen strains, characterized by higher virulence and aggressiveness. This problem is often aggravated by the lack of any concepts of an adequate fungicide use strategy. Many Russian farmers start to apply fungicides only after clear manifestations of disease symptoms As a rule, they apply 2–3 sprays with large intervals between applications, and do not care about achieving thorough coverage of all potato plants with fungicides. For seasons characterized by a low late blight incidence, farmers using such fungicide application strategy may achieve a reasonable harvest

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