Alternaria Black Spot (Alternaria brassicae) Infection Severity on Cruciferous Oilseed Crops

Viacheslav Eremeev,Peeter Lääniste,Ülo Niinemets,Eve Runno-Paurson,Luule Metspalu,Astrid Kännaste,Merili Hansen,Helina Nassar,Liina Edesi

doi:10.3390/app11188507

Abstract

The increase in the cultivation area of cruciferous oilseed crops and the use of short crop rotation has resulted in the enhanced spread of several major pests in Northern latitudes. There is currently limited information about incidence and severity of Alternaria black spot disease (Alternaria brassicae) on the main oilseed crop, spring oilseed rape (Brassica napus), in the Northern Baltics. Thus, spring oilseed rape and five alternative cruciferous oilseed crops were selected and their resistance to black spot disease was evaluated in field conditions during two growing seasons. We hypothesized that spring oilseed rape is more susceptible to Alternaria black spot disease than other alternative cruciferous oilseed crops. Both growing seasons were warmer and drier compared to the long-term average, and were thus suitable for A. brassicae development and assessments. In both years, incidence of Alternaria black spot infection was recorded on all cruciferous species, yet the disease development differed considerably among the crops. During both growing seasons, black mustard (B. nigra) plants were the most infected. Based on our observations during warm growing seasons we conclude that alternative oilseed crops such as Sinapis alba, Eruca sativa and Raphanus sativus are more resistant to the Alternaria black spot infection than the traditional oilseed crops and thus, possess a great potential to grow with limited chemical disease control in Northern Baltic conditions.

Highlights

Introduction iationsThe area of cultivation of cruciferous oilseed crops has been increasing and oilseed rape (Brassica napus var. oleifera) has become one of the most important oilseed crops worldwide [1]
In 2011, too, by the end of the growing season, the disease severity on B. napus reached up to 79%, which was the highest value among the tested species
Based on our observations in two extremely warm growing seasons in the Northern Baltics, we suggest that under favorable conditions for Alternaria black spot infection, alternative oilseed crops such as S. alba, E. sativa and R. sativus possess a great potential to grow with limited chemical inputs even in the case of conventional farming

Summary

Introduction

Introduction iationsThe area of cultivation of cruciferous oilseed crops has been increasing and oilseed rape (Brassica napus var. oleifera) has become one of the most important oilseed crops worldwide [1]. The area of cultivation of cruciferous oilseed crops has been increasing and oilseed rape Oleifera) has become one of the most important oilseed crops worldwide [1]. In Estonia, oilseed rape (B. napus) and turnip rape (B. rapa) have been important cash crops for farmers since the middle of 1990s. The area of these two cruciferous crops has stabilized at 75,000 ha [2]. The reduction in growth area is due to serious pest problems, especially for spring oilseed rape and turnip rape [5,6]. The major cruciferous pests with enhanced dispersal include several insects such as pollen beetle (Brassicogethes aeneus) [7], Licensee MDPI, Basel, Switzerland

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