Impact of Winter Cover Crop Usage in Soilborne Disease Suppressiveness in Woody Ornamental Production System

Abstract

Diseases caused by soilborne pathogens are a major limitation to field grown nursery production. The application of cover crops for soilborne disease management has not been widely investigated in a woody ornamental nursery production system. The objective of this study was to explore the impact of winter cover crops usage on soilborne disease management in that system. Soils from established field plots of red maple (Acer rubrum L.) with and without winter cover crops (crimson clover (Trifolium incarnatum L.) or triticale (× Triticosecale W.)) were sampled following the senescence of the cover crops. Separate bioassays were performed using red maple cuttings on inoculated (with Phytopythium vexans, Phytophthora nicotianae or Rhizoctonia solani) and non-inoculated field soils. The results indicated that winter cover crop usage was helpful for inducing soil disease suppressiveness. There was lower disease severity and pathogen recovery when the cover crops were used compare to the non-cover cropped soil. However, there were no differences in maple plant fresh weight and root weight between the treatments. The rhizosphere pseudomonad microbial population was also greater when the cover crops were used. Similarly, the C:N ratio of the soil was improved with the cover crop usage. Thus, in addition to improving soil structure and reducing erosion, cover crops can provide improved management of soilborne diseases. Therefore, stakeholders can consider cover crop usage as an alternative sustainable management tool against soilborne diseases in field nursery production system.

Response of Cover Crops to Phytopythium vexans, Phytophthora nicotianae, and Rhizoctonia solani, Major Soilborne Pathogens of Woody Ornamentals

“…Aside from agronomic crops and a vegetable cropping system, the use of cover crops is still in its early phase. Some studies have been conducted [19][20][21]33,34] which proved the beneficial aspects of cover crops in different crop productions, their benefits, and methods, as well as timing of application.…”

“…The use of cover crops is promising in woody ornamental production systems; however, there is a long way to go before drawing a core conclusion and making proper recommendations. A few researchers [19][20][21] screened several cover crops such as winter wheat, crimson clover, triticale, and Brassicaceae crops against soilborne plant pathogens and discovered potential benefits of the cover crops.…”

“…Although they are generally used to cover the field, more often than not they are used as green manure or animal forage. Cover crops slow soil erosion, improve soil physical (structure) [22] and chemical properties (pH balance, increase C:N ratio) [21], smother weeds, conserve moisture, and may attract beneficial insects, which prey on pests. Cover crops are also known to increase beneficial microorganisms in the soil such as Pseudomonas spp.…”

“…Cover crops are also known to increase beneficial microorganisms in the soil such as Pseudomonas spp. as well as increase soil disease suppressiveness [19,21]. Although the use of cover crops is generally confined to agronomic and vegetable crops, their benefits in woody ornamental production systems are also being realized.…”

Special Issue “Integrated Defense Responses in Crops against Soil-Borne Pathogens”

“…Adapted agricultural practice is a promising strategy to decrease yield losses by soil-borne pathogens. Winter cover crops reduced the disease severity in red maple nursery production when inoculated with different soil pathogenic fungi [9]. The possibility of crop rotation between sugar beet and oilseed rape was addressed with respect to limiting the occurrence of beet cyst nematode [10].…”