Biocontrol of Fusarium circinatum Infection of Young Pinus radiata Trees

Abstract

Pitch canker, caused by the fungus Fusarium circinatum, is a major disease of Pinus radiata currently controlled to some extent in nurseries by good hygiene and application of synthetic fungicides. The aim of this study was to evaluate alternative strategies to control fungal infections in nurseries and young pine plantations. The antagonistic effects of biocontrol bacteria and essential oils against F. circinatum in vitro and in young P. radiata trees were assessed. Pseudomonas fluorescens, Erwinia billingiae, and Bacillus simplex reduced the growth of the fungus in vitro by 17%-29%, and decreased the density of the mycelial mat. In young P. radiata trees, the length of F. circinatum lesions was reduced by 22%-25% by the same bacterial strains. Direct application of cinnamon and/or clove essential oils to wounds in stems of two-year-old P. radiata trees also limited the damage caused by F. circinatum. Lesion length was reduced by 51% following treatment with cinnamon oil (10% v/v), and by 45% following treatment with clove oil (15% v/v) or a combination of both oils. However, the oils were toxic to younger trees. The biocontrol bacteria and essential oils show promise as prophylactic treatments to reduce the devastating effects of F. circinatum on P. radiata.

Environmentally friendly methods for controlling pine pitch canker

“…Although the use of endophytic bacteria to control Fusarium species is common in agricultural crops (Singh et al ., ), the available information on bacteria as BCAs of forest tree diseases is comparatively scarce. Pseudomonas fluorescens , Bacillus simplex and Erwinia billingiae isolated from the endorhizosphere of a symptomless P. radiata pine reduced mycelial growth of F. circinatum in vitro and lesion lengths on 2‐year‐old P. radiata seedlings inoculated with the pathogen by 17–29% and 22–25%, respectively (Iturritxa et al ., ). Bacillus subtilis and Burkholderia sp.…”

“…() screened several essential oils against growth of F. circinatum and found that the most effective oils were those obtained from oregano, Japanese mint and cinnamon, all being 100% inhibitory at the lowest dose tested (10% v/v essential oil dilution). Cinnamon, fennel and clove oils also reduced or inhibited (partially or completely) the in vitro growth of F. circinatum , showing both fungicidal and fungistatic effects (Iturritxa et al ., ). Antagonistic effects were also demonstrated in inoculated seeds of P. radiata using thyme oil (Iturritxa et al ., ) and in 2‐year‐old P. radiata seedlings using cinnamon, clove or a mixture of the two with promising results on the control of F. circinatum , although phytotoxic effects were noted on 1‐year‐old plant tissues (Iturritxa et al ., ).…”

“…() who demonstrated that chitosan oligomers and phosphite salts were able to inhibit mycelial growth of F. circinatum in vitro . As noted above, pine rhizobacterial isolates of E. billingiae and P. fluorescens protected young P. radiata seedlings against F. circinatum (Iturritxa et al ., ), probably as a consequence of a combined effect of mycelial growth inhibition and induced resistance.…”

“…Germination of P. radiata seed was inhibited following treatment with essential oils of thyme, tea tree, oregano, niaouli, cinnamon and red thyme. Phytotoxicity seems to be age-dependent, because after application of cinnamon or clove oils to 1-year-old seedlings, epinasty or curling and twisting of needles and stems followed by necrosis occurred, but the effect was not observed in 2-year-old plants (Iturritxa et al, 2011(Iturritxa et al, , 2017.…”

Isolation and Characterization of Potential Isolates of Rhizosphere Bacteria to Contro Budok Disease in Patchouli Plant

“…dilaporkan dapat mengendalikan F. oxysporum f.sp. cubense pada tanaman pisang (Pushpavathi dan Dash 2017), Sclerotium rolfsii Sacc pada kacang tanah (Rakh et al 2017), dan F. circinatum pada tanaman pinus (Iturritxa et al 2017). Selain itu, Pseudomonas sp., juga dilaporkan dapat mengendalikan Ralstonia solanacearum yang menyerang tanaman kentang dan terung (Kheirandish dan Harighi 2015;Ramesh dan Phakde 2012).…”