Effect of Winter Oilseed Rape Cropping on the Development of the Sugar Beet Cyst Nematode, Heterodera schachtii, and Control of Volunteer Plants as a Trap Crop Method

Daub Matthias

doi:10.3390/agronomy10030355

Abstract

The integration of oilseed rape (OSR) into sugar beet rotation systems is restricted due to the very good host status of OSR for the beet cyst nematode (BCN) Heterodera schachtii. In contrast to sugar beet, the cultivation of winter OSR covers a longer period, but at a lower soil temperature regime. Thus, presumably one or two generations of BCN may develop during the cultivation of winter OSR, resulting in moderate multiplication rates of 1–2 in the present study. This multiplication rate was year-dependent, but not affected by different sowing times. For the first time, the present study identified volunteer OSR emerging in high densities post-harvest as a major risk for a high multiplication of BCN at optimum temperatures. The emergence of BCN females with offspring was observed very early, resulting in a significant population increase before 350-degree days (>8 °C) in inoculation experiments and in field investigations. Conducting treatment trials with glyphosate to control volunteer OSR in micro-plots and field experiments confirmed effective suppression of BCN reproduction when growth of volunteer OSR was interrupted at 250–350-degree days. Thus, data gained from BCN reproduction studies under controlled and field conditions provided a unique basis for the development of a trap crop method. The degree day model has been successfully implemented as part of an open access management tool.

Highlights

The beet cyst nematode (Heterodera schachtii Schmidt, 1871) is a major pest of sugar beet, with severe economic damage potential [1], which occurs worldwide throughout different geographic and climatic regions [2]
Ever since Julius Kühn [4] identified oilseed rape (Brassica napus L.) as a host of the beet cyst nematode (BCN), it has been widely accepted that the integration of OSR into crop rotation systems with sugar beet should be avoided [5,6] to minimize the potential risks of an uncontrolled population increase of BCN [7]
The most of 14 dominant development stage detected in OSR roots at the5 first sampling date (45%–60% of all individuals) and from sampling date 4 (>80%) onwards

Summary

Introduction

The beet cyst nematode (Heterodera schachtii Schmidt, 1871) is a major pest of sugar beet, with severe economic damage potential [1], which occurs worldwide throughout different geographic and climatic regions [2]. Oilseed rape (OSR) is considered tolerant against Heterodera schachtii, but is a very good host with high reproduction potential for the nematode [3]. Ever since Julius Kühn [4] identified oilseed rape (Brassica napus L.) as a host of the beet cyst nematode (BCN), it has been widely accepted that the integration of OSR into crop rotation systems with sugar beet should be avoided [5,6] to minimize the potential risks of an uncontrolled population increase of BCN [7]. Resistance against BCN was transferred successfully from Raphanus sativus L. to Brassica napus L., resulting in a new BCN-resistant plant Raparadish (×Brassicoraphanus, 2n = 38) with low agricultural value [8]. BCN-resistant OSR cultivars are not yet available to growers in Europe

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