Valerian (Valeriana officinalis L.) tolerance to some post-emergence herbicides

Abstract

Valerian (Valeriana officinalis L.) is a medicinal plant, but its cultivation is restricted by weed competition. Therefore, three rates (0.75X, 1X, and 1.25X, where X is equal to the recommended dose of haloxyfop-R (methyl ester), sethoxydim, oxadiargyl, bentazon, oxadiazon, and oxyfluorfen) were applied at the 3-4 leaf stages to valerian plants. This application was done to select the herbicide type and rate for post-controlling broadleaf and grasses weeds in this species. Herbicide injury, Soil-Plant Analyses Development (SPAD) reading, number of leaves per plant, stem diameter, and fresh and dry weights were determined 10, 20, and 30 days after herbicide application. Oxyfluorfen application caused the most herbicide injury followed by bentazon. Injury increased as the rate and the days after application increased. Oxadiazon only caused significant damage 30 days after application under all three rates. Other treatments showed no marked injuries under any rate or date after application, as compared with the control. Effects on other measured traits depended on the trait, herbicide, and herbicide rate. The highest SPAD, leaf number, shoot diameter, fresh weight and dry weight, was recorded under application of 30 mg a.i. ∙ kg-1soil oxadiargyl and 90 mg a.i. ∙ kg-1soil oxadiazon, 81 mg a.i. ∙ kg-1soil haloxyfop-R, 37.5 mg a.i. ∙ kg-1soil oxadiargyl, 22.5 mg a.i. ∙ kg-1soil oxadiargyl, 81 mg a.i. ∙ kg-1soil haloxyfop-R, and 81 mg a.i. ∙ kg-1soil haloxyfop-R, respectively. To sum up, the results showed that sethoxydim, oxadiargyl, and haloxyfop-R produced no significant symptoms of phytotoxicity or reduction of measured traits. This means that oxadiargyl, haloxyfop-R, and sethoxydim may be used safely for weed control of valerian at the rates used in this experiment under similar conditions.

The variability of population and individual traits of medicinal plant Valeriana officinalis L. var. officinalis Mikan under different site conditions

“…The obtained results proving that the number and length of flowering stems, as well as the number of flowers augments in subsequent study sites, is in contrast to previous findings (13), proving that number of flowering stems in Valeriana officinalis var. officinalis augments with diminishing plant density.…”

“…Currently, one of medicinal taxa suffering the progressive loss of populations as a result of habitat degradation is Valeriana officinalis L. To date, the ecological investigations of the aforementioned taxon have focused on studies of the relation among yield quality and: date of sowing (9), planting density (10,11), fertiliser application (12), weed control methods use (13), inoculation of roots with bacteria strains (14,15), planting method (16 ), and developmental stage (17). As a result of the scarcity of studies conducted in natural localities, the present investigations were carried out, aimed at an evaluation of the impact of habitat conditions on population and individual traits of Valeriana officinalis L. var.…”

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“…Valerian produced shorter roots in the oxadiargyl treatment in comparison manual weeding treatment. It means that this species was not tolerated to oxadiargyl in contrast with the results of Monjezi et al (2015). Oxadiargyl herbicide inhibits the enzyme which is in the pigment synthesis pathway (Boger and Wakabayashi, 1995).…”

“…Hand weeding is the most popular method of removing weeds of valerian in Iran but it is costly and time consuming method. Monjezi et al (2015) suggested that oxadiargyl, haloxyfop-R and sethoxydim may be used safely for weed control of valerian in Iran and reported application of oxadiargyl resulted in no marked injury to valerian. The demand for integrated weed management approaches has resulted from increasing energy, labor, and material costs associated with weed control practices in conventional cropping systems (Feldman et al 2000).…”

Effects of light-dependent herbicides on growth and physiology of Salvia officinalis

“…Oxadiazon provided good weed control and increased the shoot dry matter of marjoram (Origanum syriacum) (Qasem and Foy, 2006). The effects of broadleaved and grass weed herbicides application in Valeriana officinalis showed that oxyfluorfen and bentazon caused severe damage to V. officinalis, while oxadiargyl, oxadiazon, sethoxydim, and haloxyfop-R (methyl ester) did not injure the crop (Monjezi et al, 2015). Application of desmedipham and phenmedipham after the four-leafpair stage of calendula (Calendula officinalis L.) controlled several weed species and avoid injury to calendula (Forcella et al, 2012).…”