Susceptibility of intercrops to infection with Rhizoctonia solani AG 2‐2 IIIB and influence on subsequently cultivated sugar beet

Abstract

The susceptibility of intercrop species (Raphanus sativus, Brassica juncea, B. rapa, Sinapis alba and Phacelia tanacetifolia) to the sugar beet pathogen Rhizoctonia solani was investigated in vitro, in the greenhouse and in the field with artificial inoculation. Disease severity in subsequently cultivated sugar beet was monitored in the field. Differences in susceptibility between species were found to be consistent in all experimental systems. All intercrop species were susceptible to R. solani. Brassica rapa and R. sativus were less susceptible than P. tanacetifolia. Compared to fallow, the cultivation of B. rapa and R. sativus reduced disease severity in subsequently grown sugar beet (median ratings of up to 3AE0 and 3AE5, respectively, depending on environmental conditions). This resulted in higher white sugar yield compared to fallow (up to 210% and 157% for B. rapa and R. sativus, respectively). This study demonstrates that in vitro and greenhouse resistance tests are suitable systems to predict the effects of intercrop species susceptibility in the field on disease severity and white sugar yield in subsequently grown sugar beet. Intercrop breeding programmes might profit from fast and efficient screening tests to provide Rhizoctoniaresistant intercrops as an additional control measure against R. solani in sugar beet.

Plant: soil interactions in temperate multi-cropping production systems

“…When intercropping mustard and radish (Raphanus sativus) in rotation before sugar beet Motisi et al (2009) found reductions in R. solani pathogen levels in sugar beet, however, reductions have also been observed in intercrops with brassica, and nonbrassica species (Kluth et al 2010). Direct effects of biofumigation cannot account for the overall level in disease reductions.…”

“…), marigold and some tropical legumes, such as velvet bean (Mucuna deeringiana), are beneficial component crop species, with high nematodal suppressive potential through the production of biofumigant secondary metabolites and partly through stimulation of antagonistic microorganisms (Liebman 1995;Halbrendt 1996;Kloepper et al 1999;Abawi and Widmer 2000). Kluth et al (2010) found that allelopathic traits of mustard and oilseed radish (Raphanus sativus) cultivars when intercropped successfully reduced nematode infestations in the following sugar beet crop, when residues were incorporated into the soil (biofumigation).…”

“…Tree based intercropping systems (TBIs) are referred to as alleycropping or agroforestry. Vegetables have long been intercropped in horticultural systems, but have also been trialled in agricultural settings (Motisi et al 2009;Kluth et al 2010;Zhou et al 2011).…”

Anastomosis Groups of Rhizoctonia solani associated with tomato foot rot in Pothohar Region of Pakistan

“…In present studies, Rio Grande was the most susceptible to R. solani infection. It is well accepted that the occurrence of soil-borne pathogens including R. solani is greatly influenced by intensive cropping 54–56 . Solanaceous vegetable cultivation on the same fields also helps in the inoculum multiplication, however, this pathogen is also well adapted for life outside the host plants 47,57 .…”

Crotalaria spectabilis and Raphanus sativus as Previous Crops Show Promise for the Control of Bacterial Wilt of Tomato Without Reducing Bacterial Populations

“…The antagonistic properties of T. patula towards R. solanacearum were due to the presence of thiophenes in its root exudates (Tang et al 1987;Terblanche and de Villiers 1998). Under natural conditions, several other mechanisms and interactions may also need to be taken into account, for example an antagonistic microbial community in the soil could be reduced or increased during the growth phase of different previous crops (Kluth et al 2010). Concerning Brassicaceae, the present study demonstrated that the density of R. solanacearum in the rhizosphere of R. sativus cv.…”