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Date: Fri 11 Dec 2020 7:00 AM AWST
Source: Farm Weekly [edited]
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Increased rhizoctonia bare patches in cereals have been observed around WA [Western Australia] this [2020] season. Daniel Hueberli, Department of Primary Industries and Regional Development WA (DPIRD), said the main reason for the higher levels of rhizoctonia was late rain and the subsequent later emergence of crops in a lot of regions.
"The 2nd reason was that growers were likely sowing into a high inoculum load, most of the paddocks probably had some cereals in there previously. We also had a very dry summer in 2019/20 and the pathogen inoculum can survive well in dry conditions." However, if paddocks had canola in 2019, the pathogen inoculum would have dropped considerably and less disease would have been evident.
Dr Hueberli said the management of rhizoctonia required an integrated approach to reduce inoculum and control infection and impact on yield.
He said sowing early, if the season allowed, meant the plant could benefit from warmer soils, allowing the roots to get ahead of the pathogen. Disturbance below the seed at sowing promotes rapid root growth away from the rhizoctonia and disrupts hyphal networks, with the ideal depth being at least 10 centimetres [about 4 in] below the seed.
[Byline: Shannon Beattie]
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Communicated by: ProMED-mail <promed@promedmail.org>
[_Rhizoctonia solani_ (Rs; synonym _Thanatephorus cucumeris_) is a ubiquitous soil borne fungus associated with damping-off, root rot, basal stem rot (foot rot), and fruit rot in a large number of crops, including cereals, pasture grasses, oilseed rape and pulses. The fungus causes crop damage by pruning the root system, which results in water and nutrient stress to the plant. A number of fungal anastomosis groups (AG) have been identified, according to hyphal incompatibility.
They vary in host specificity, different AGs affect monocotyledons (such as cereals) and dicotyledons (including brassicas). Hosts are generally most susceptible in the seedling stage. Yield losses of up to 50 percent have been reported in cereal crops.
The pathogen survives in the upper soil, compost and infected plant debris, inoculum levels increase on the roots of host plants. Since the fungus has a wide host range, it is difficult to control by crop rotation. Disease management may include seed treatments, cultural practices (such as fertiliser applications, timing of planting, weed management during non-crop periods, selection of the style of seed drill) and use of resistant crop varieties.
High levels of inoculum in the soil increase the risk of crop damage.
Other factors, especially soil suppressive activity, which is a function of the population, activity and composition of the soil microbial community, also play a role in disease development.
Simultaneous high soil inoculum and reduced soil suppressive activity compound the rhizoctonia risk further.
In Australia, the practice of herbicides replacing the plough to improve soil properties and prevent land degradation has been widely adopted. However, the resulting build-up of organic matter and preservation of fungal structures in the soil favours the pathogen and consequently these direct-drilled cropping systems often face very serious rhizoctonia problems.
Maps
Australia (with states):
<https://url.emailprotection.link/?bHR8Q3Az0pc6A4C6_mFlo0W3yus-cV8PybiBgd9jCLGSkwEKS4cOXC87ldlRs3_GnN_zd_woz9faU2EdGc2gUH_6VC1cUzGbTxu3nL2wp7Qng86fRkMOsG9VfQ2K11X28> and <https://url.emailprotection.link/?b05QFwqPTij9Or0JNntK2Ta028HK0Hy9cXDrxF4Qezb32ptmAe6WjmbTgL-CyGV9yqNvzL3KwjXK_rwsdueMoFg~~>
Pictures
Rs on wheat:
<https://url.emailprotection.link/?bJAjwg7PtPJOq4OOVjArbXnLXXazIkRQ0pop4Kfm7CiDJ8gQ5kYz1ReAL1Qnv5rU3oLqUwEv13FVS6r2yr23TiyRo924VH5cfPw3gY6BPIfknbTQQZL8MGY_V5qCYttytlHAPwsVbr0898L5C3apkQf4Jul6wI2XHF_P7zxoq3A8~>,
<https://url.emailprotection.link/?b04CqLY6uWVaU6N2cp4EjfkpST_6-_rZ4NtFOS_cQ_wdj98FhGRzNgmo-hGlfNfdU6HHVb6uzkATLd4G_xPVmT2Z_LPXJVPzjTRP_LiZZ_IrmgHRXK65huWjRCP_rW-mbA4-kMNppsnsZaAG2BVAAlpZAvR7akm3oCu2GIpIlOyQ~>,
and
<https://url.emailprotection.link/?bUFyvJvJ7npvlqgvqVlFU6BtUGjv0WjcJ-3Wt0058Sl-fk_mEFONtWDjQl_Z2_j9oDnvii0KcSnPmQBLQwPjiOe0l5geW7gkCOxqOYhxPHvhGG6_tG-59DZbgeafJggDE>
Rs on oilseed rape:
<https://url.emailprotection.link/?bn1ODFk-jzvds-pWS_6pG22bJxOmpNGGwayO1zFCilpwFUjjVfAENRkQt6W9DxySKJKhx_578ky8cFEptFmMIlVwok7ZBAGn5jCIGd5wey_8YiLe4xemo8srctTPxfJaaYnxDcgpJEo3UkfkqfW3yur388vkgszJpajIbiEXFlDVeGp8-02J1rgCvrAG_EW0czUt4BFvyFcZz3A9MVSDPgOLoJ5QaEWmRIvSkWMX7BxNnEvsQBjZRvlLwHLDD4R3F>
and
<https://url.emailprotection.link/?bz5zIZVQ40_z_-naP_-FFiieR21daqs9jUGudxekU9N-7cGj0b3uUp2eWccYGPMAQcwOxkfU4lLOMqvKkvR5w6TMF5jK9laTJZ9wlamBomQg-XCOM3NBnKtYbsAEoPtmhfwr4SpL82V3BKK3n56RAvYRhqiCOxKXS1SnJS1yeSL6dsAMT9DbPrEi87JAZ8SVu5lj-p4KRoc8QwXczjRQ9dg~~>
Links
Rs in cereals and other hosts:
<https://url.emailprotection.link/?bytBg_LVRm5zp6LCAlOMhikRFw_S-wSZ6Xr6_nzg-3QJLU-vAcIc1XxnsJR1fkQKorM2Sr8ZfKosdkQN-HidxJSH9O97CkXdLYv5P6A15_U69S04T-qte2kGsd1CCyj4A>,
<https://url.emailprotection.link/?bVw0DW8hZeK33Aew1VdxK7UwMUM6qbqnxbNgj_eMnk7FH_JSL9ptvL9O7GEt63xKA9xpTWhf8R61xHdB4LgVc6MvDWbItxozeLq3FEfdvqc3pdi-juOmmOJe3CLjIlGub>,
<https://url.emailprotection.link/?baMYyOLcvsPVlOKpfDWk_dNrtORTqce33sefICsBcpoQwvmv37rQEHC309uVU7H7TuzubC-gs3UZGs0g1PvpOuCpmXUij5rJxVfJqYx4R5gKmySNTZEPNKvCusBzhW6sy>,
<https://url.emailprotection.link/?bXv--ilstHhcydOFJWX_m3G9jC4fe03R4K_M2Mn6M7Y3tBAQS9q1jZXyv1riD7b-cEr438hIq5FY8mNmycqHOkFBgwMfwnetJJKGxpk4roWIPp6lRFl6J25xABqcvuzf6aSINXLSPm0P2rPLc_udZ2qWoQZWcIBV-TRMadlBMMe4~>,
<https://url.emailprotection.link/?bCgzFnbGS-3Wx4Z4LdelxnLtPfnp9qfKooiMta6NVFK8Y1FPvRXXgArjGJ0AJIiYxh83ZBeWPA53F94BczJYzWVH6nUuAh2s7D8FzRoCKAxAfQWxKue9QOBfkaDMLW2O5>,
<https://url.emailprotection.link/?bsaXA3_PB_VokA7j3tv0aeLMruMi9WycxW87ZOO81V9oLvIRcYv3r4Ly1f9M4PzsA59tBeIXG6HbTbgKfI_buYQ~~>, and <https://url.emailprotection.link/?bmkA-3RlvX9C63QUzHqM5_7fHBz-cR0WAUjuPTmEsXXOf7sj5fazPF4A6lL-B-7zPSTquYayS8Nzb8Pn983s8mKh2PiK7nWaH-DCmh0j9r_h-6TJFPZEOfCYm6OWLYwDD>
R. solani_ taxonomy and synonyms:
<https://url.emailprotection.link/?b1Q_tZlsNsEMwUDGd0sClUdON81dZdAu7kgvoLyZMiNuQwiA6AUyX7yAAVgLKHf5FXUKBTF8pLsBalSm95qIXhYHrAKslGpwteppxuLI5EJa1205xri2cniaa1puHMvll>
and
<https://url.emailprotection.link/?bj-3WqUa7mf4idw8mjv2KOmMmfKj7QPtetXGj8xy5IaLP6I69mNIfM2sDcQjfqdXKuuSePDyiCeKCyDfSHRiUhqNOLfbA3khYxNaA57e3qw7nOPKzO3HBrw4m8fvRRgxk>
DPIRD WA:
<https://url.emailprotection.link/?b8bZ0iXaT1cMgQpG_D4MBit-KzcXGAM7TEMMxExU9PO5tc0Rp15cpskQKCakgxC5Pq15J-xegmj-lqH92Wl1Tkg~~>
- Mod.DHA]
[See Also:
2019
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Rhizoctonia, oilseed rape - UK: (England) https://url.emailprotection.link/?b5abiJ5f6vWhzOUoRoYi510ms05txAqhpykS7nkpMXwxF9-pGRSh-Thg6gyFVYmeoPsyC40AVX6UTYUytOkdcK55CY8T3S9or7NTOoBFTAntCwQcSIdR_4IG0MLqSV-Y_
2017
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Fungal root rots, sugar beet - UK: (East Anglia) https://url.emailprotection.link/?bxVkHJoHsFK0ohhtIGXFfjpn313n9Lt4LlZKkqu4OC2bMfvtln4sYzo75FgKZJ4pVYnvwUPdV6FF66735aPy5kJmJZ3YwMK7AnDgSaGHlDFCgpP5EDYaPEQWl-8RDCZGK
2016
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Blast & sheath blight, rice - Philippines: (II) https://url.emailprotection.link/?bAohQ7bnq35p7QYjVWTxO7cxgIgI8fd2RtikUVU7hm-Hsjh_s0rnYaMtZvlBPWQ1ZXMCOSMSMC0IyJuwtcSimrrQrKSVD5-y-XKQ3shSfgP1hwK4myCtgo9ciV5lL_ggI
2015
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Sheath blight, rice - India: (PB)
https://url.emailprotection.link/?b3d9N7A7CIFCVdSPXzgTKW4hxF0XDEMo8bdRSWO0xbEKCkde7dpnm-xP0GBnw55n2RDFnYK7BaNjI8p1TV9iUQe2GD9KkzYl_w8d6aI4H-1wbl2WO_Ur8x8cbgKYQNrVW
2009
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Leaf & sheath blights, rice - India: (PB) https://url.emailprotection.link/?bgls2lG8Pmqqj2wzYboGFSajE6rYjD-c0B3tFRtZfPTBXwQ-mFik9kcQ6TdXDfKH5CXbvZcZMxLftPKZh2sugKFTd6xUwA9KBrCay7ncCYogcmKFDFrUfp6Bkippze-0Y
Rhizoctonia, cereal crops - Australia: alert https://url.emailprotection.link/?b3eKzuU2uYXub2pFWCyuODeSH5fuSpHJtRIKFLw-0BCfW9EAQyfVEF9DhHzLL7KvWenOE3Pj-Mrb2_F0buqqVvdjfG6sipOUdMAE_J0ZIiYpW0bMkbhOVBixTIs6TKrKP
2007
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Rice diseases - Bangladesh https://url.emailprotection.link/?bkD4xPA0R0sU425M8iRlq6R2RLfr4acLrk3dBopG2hBpv84B8H-2zx8KAetYDkmKtp0ypTsKHqqfmkrZH-XqXj8L97UcHlCgjl77I8J00h0_2zwqCUJQRTzGxf8z9Rn-Y
Fungal disease, cardamom - India (Kerala) https://url.emailprotection.link/?b9DP6qSlDl-23DMBQOG_g63ILDCKUKrKIBRmiQVlUAlkKc0eT9XBUmtgkAc5bGontXWkeTjz5-INlzgYIXTihaddN048avD3PKymAM1I04pvq5gWUkjYIBdt4X9GeuHea
Sheath blight, rice - USA (MS)
https://url.emailprotection.link/?bGg3gZliV81OFFn-SmW-8dadOZdADLSBC2YGs_gQYmyO8xqUvSBDuU9fWWxBCQSpS90x867O9hKKh8O6-3B44xIwSTrgeByb_LoHlI7YeNikWxgeqkTtVKVC8ssY1VHRv
Rhizoctonia root rot - Australia (SA)
https://url.emailprotection.link/?bEp519v-IHKNwX0FDHEVSohswwL5vyhjzAo9XbAqEhgW-njtp4Y_YhlB7ozaW2ugDqgaZ1L_ogQdRZmyQPWbl0S61dv5yC9SIbP_gvoaoS-uSyVFQk_l7dFmIVtYV4fEi]
Topics
Species
