Effects of Cover Crops on Pratylenchus penetrans and the Nematode Community in Carrot Production

Abstract

Cover cropping is a common practice in U.S. Midwest carrot production for soil conservation, and may affect soil ecology and plant-parasitic nematodes-to which carrots are very susceptible. This study assessed the impact of cover crops-oats (Avena sativa), radish (Raphanus sativus) cv. Defender, rape (Brassica napus) cv. Dwarf Essex, and a mixture of oats and radish-on plantparasitic nematodes and soil ecology based on the nematode community in Michigan carrot production systems. Research was conducted at two field sites where cover crops were grown in Fall 2014 preceding Summer 2015 carrot production. At Site 1, rootlesion (Pratylenchus penetrans) and stunt (Tylenchorhynchus sp.) nematodes were present at low population densities (less than 25 nematodes/100 cm 3 soil), but were not significantly affected (P . 0.05) by cover crops. At Site 2, P. penetrans population densities were increased (P # 0.05) by 'Defender' radish compared to other cover crops or fallow control during cover crop growth and midseason carrot production. At both sites, there were few short-term impacts of cover cropping on soil ecology based on the nematode community. At Site 1, only at carrot harvest, radish-oats mixture and 'Dwarf Essex' rape alone enriched the soil food web based on the enrichment index (P # 0.05) while rape and radish increased structure index values. At Site 2, bacterivore abundance was increased by oats or radish cover crops compared to control, but only during carrot production. In general, cover crops did not affect the nematode community until nearly a year after cover crop growth suggesting that changes in the soil community following cover cropping may be gradual.

Pratylenchus penetrans, a potential risk in glasshouse-grown lettuce: population dynamics and damage threshold

“…It is known that black fallow in general has a negative effect on the population of P. penetrans (Pudasaini et al, 2006;Viaene et al, 2006). However, it was reported that at low population densities the number of nematodes can remain the same (Grabau et al, 2017). Although low densities were observed in our study, the population surprisingly increased sometimes after 3 months of black fallow in winter.…”

Wheat Production Alters Soil Microbial Profiles and Enhances Beneficial Microbes in Double-Cropping Soybean

“…Similarly, Tyler et al (1987) discussed that long-term tillage affected SCN population densities only 3 or 4 years after the establishment of their cropping system. Soil ecosystems may require attaining some degree of equilibrium before suppressiveness is noted, which implies that shifts in soil microbial communities due to cultural practices are incremental (Yeates et al, 1999;Venter et al, 2016;Grabau et al, 2017).…”

Volatile compounds as potential bio-fumigants against plant-parasitic nematodes – a mini review

“…The use of Brassica and non-Brassica plants as biofumigation crops can be through maceration and incorporation of plant parts into the soil as green manure, through the use of seed meal, or as poor-host winter or summer cover crops (Hafez and Sundararaj, 2009;Rahman and Somers, 2005;Smith et al, 2004). Biofumigation is usually not as effective as chemical fumigation and biofumigant crops can also be good hosts to some of the target PPNs (Daryanto et al, 2018;Grabau et al, 2017;Monfort et al, 2007). The cost of biofumigation is still high and often not economically practical for farmers to apply (Clay et al, 2020;Dutta et al, 2019).…”