Effects of a foliar fertilizer containing boron on the development of Sclerotinia stem rot (Sclerotinia sclerotiorum) on canola (Brassica napus L.) leaves

Abstract

Sclerotinia stem rot (Sclerotinia sclerotiorum Lib. De Bary) is one of the most destructive fungal diseases on canola (Brassica napus L.). The effect of a foliar fertilizer containing 3% boron (Active Flower™ [AF]) in reducing disease severity was evaluated. AF at 0.1, 0.3 and 0.5 ml/100 ml was first tested for growth inhibition of S. sclerotiorum in potato dextrose broth. Growth was reduced at 0.5 ml/100 ml by around 90%. Boric acid (BA), an important component of AF, was tested against fungal growth at 10 ml/L, and no significant effect (p = .05) was found. Foliar applications of AF and AF formulation that did not contain boron at 0.1, 0.3 and 0.5 ml/100 ml were made weekly to canola ‘Westar’ grown under greenhouse conditions. Treatments were also made with BA at 10 ml/L to canola plants. After four applications, AF at 0.5 ml/100 ml and BA at 10 ml/L enhanced boron levels in leaves by fivefold and threefold, respectively, compared with the control. Lesion size of S. sclerotiorum on detached leaves was significantly (p < .05) reduced by AF at 0.5 ml/100 ml, but lesion size was not reduced on AFWB‐treated leaves. Experiments were repeated twice with the same results. Levels of phenolic compounds in leaves treated with 0.5 ml/100 ml AF were enhanced by twofold compared with the control. There were no significant differences in lignin, peroxidase (POD) or polyphenoloxidase (PPO) between the control and AF treatments. These results suggest that enhanced boron levels in canola leaves were associated with a suppressive effect on disease due to S. sclerotiorum.

Evaluation of disease management approaches for powdery mildew onCannabis sativaL. (marijuana) plants

“…Boric acid as a foliar spray also significantly reduced the number of lesions per flag leaf when used to treat tan spot on wheat (Simoglou and Dordas 2006). Canola plants treated with boric acid had twice the levels of boron in leaves compared to control plants and development of Sclerotinia sclerotiorum was significantly reduced (Ni and Punja 2020a). In our study, although applications of boric acid provided a significant reduction in disease in two out of three trials, the low average disease reduction in all three trials (less than 50%) indicates it is not an effective option for powdery mildew management.…”

Silicon and boron on cauliflower induce attractiveness and mortality in Plutella xylostella

“…34 Another mode of action of boric acid is the abrasiveness of the particles to the insect cuticle, 30,35,36 which may favor pest mortality when the element is applied onto the plants during fertilization. The use of this micronutrient via leaf is able to control diseases in brassicas, 15 therefore, such management can also cause the mortality of P. xylostella by topic application, which was not studied in this research.…”

“…The K concentration was balanced in the plots without Si. Both sources are used as foliar fertilizers in brassica 14,15 . Thirty days after spraying, the leaves were collected.…”

“…Both sources are used as foliar fertilizers in brassica. 14,15 Thirty days after spraying, the leaves were collected. Three leaves were collected per plot, one used in the analysis with P. xylostella and the others used for the chemical analyses of the elements and determination of leaf firmness.…”

Application of pimaricin against potato white mould

“…The disease causes a considerable yield loss in many potato‐growing regions of Hamedan province, Iran (Ojaghian, 2011). Due to considerable crop damage, lack of highly resistant cultivars and difficulty of managing sclerotinia diseases, a significant amount of research is currently being focused on this pathogen (Ni & Punja, 2020; Ojaghian et al., 2019a,b). S. sclerotiorum is a soil‐borne fungus that overwinters as long‐lasting sclerotia in soil.…”