Biocontrol Endotherapy with Trichoderma spp. and Bacillus amyloliquefaciens against Phytophthora spp.: A Comparative Study with Phosphite Treatment on Quercus robur and Fagus sylvatica

Abstract

Phytophthora species are particularly aggressive plant pathogens and are often associated with the decline of many tree species, including oak and beech. Several fungi and bacteria species are known as potential antagonists usable as biological control agents. Phosphonate (H 3 PO 3 ), commonly branded as phosphite, has also been used in the past years to protect trees against invasive Phytophthora spp.. This study aimed at comparing the effects of selected antagonist microorganisms and phosphonate, when applied by microinjection or leaf treatment. Antagonistic species were first selected for their high inhibitory activity against problematic Phytophthora species, such as Phytophthora cactorum, P. quercina and P. plurivora attacking Quercus robur and Fagus sylvatica in Polish forests. Three endophytic species Trichoderma atroviride (two strains), T. harzianum and Bacillus amyloliquefaciens showed a high control activity, and their efficacy was then assessed in comparison with a phosphonate treatment. Two application methods were experimented in this study: injection of a solution of spores or phosphonate into the sap vessels of beech or a foliar treatment on oak. Phosphonate and two strains of Trichoderma significantly reduced the necrotic area on oak leaves inoculated with P. plurivora and one strain of T. atroviride significantly reduced necrotic areas on beech branches. These results are therefore promising of a novel way to control Phytophthora spp. in forest stands and nurseries.

Trunk Injection Delivery of Biocontrol Strains of Trichoderma spp. Effectively Suppresses Nut Rot by Gnomoniopsis castaneae in Chestnut (Castanea sativa Mill.)

“…In this work, endotherapy was exploited to deliver Trichoderma BCAs against G. castaneae directly in the stem of cultivated chestnut trees. Results were promising and consistent with those obtained by Berger et al [ 27 ], who injected T. atroviride in Quercus robur and Fagus sylvatica using endotherapy as a preventive strategy against Phytophthora spp. infections.…”

“…The efficacy of endotherapic treatments coupled with the use of Trichoderma spp. has already been demonstrated by Berger et al [ 27 ], who tested the method against Phytophthora species on Quercus robur and Fagus sylvatica . The aim of this study was to assess the effectiveness of some Trichoderma species for controlling G. castaneae rot in chestnut fruits, by delivering selected strains of these BCAs in cultivated C. sativa trees by trunk injections, using a minimally invasive technique.…”

“…The concentration of conidial suspensions was then adjusted to 10 8 conidia/mL of water by using a counting chamber. The final dose of the fungal mixture utilized in trunk injections was 0.8 mL/10 cm of trunk circumference, following Berger et al [ 27 ].…”

Plant Beneficial Microbes Controlling Late Blight Pathogen, Phytophthora infestans

“…In the thick of various beneficial microbes have been investigated by several scientists, Trichoderma genera is a well-known biocontrol fungi that has been used since the 1930s to help plants acquire nutrients and control the plant pathogens [78]. Several Trichoderma species have been developed commercially as biofungicides and biofertilizers.…”