Zacharias Pretorius

#Rust of #Ehrharta calycina. Probably #Uromyces quaggafonteinus according to Berndt & Wood (2012). From Wonderfontein, Northern Cape, ZA.

#Rust on #Bromus pectinatus most likely caused by #Puccinia recondita. From Northern Cape, ZA. Any suggestions on the f. sp.?@striiformis, @wheatpath

Bunch rot of Chardonnay grapes following a spell of wet weather in the Western Cape, ZA. @JDPretorius #Botrytiscinerea

Poplar #rust is a common and widespread disease of #Populus species in South Africa. Analysis of recent samples from the Western Cape and Free State provinces confirmed #Melampsora larici-populina in all cases. Thanks Botma Visser, @B12272396Willem and @LandbouLisa for helping.

Common #bunt of #wheat (#Triticum aestivum) caused by #Tilletia laevis, a disease rarely seen in South Africa these days. From the 2024 wheat harvest, Northern Cape, ZA.

Yellow rust on leaves, sepals, and fruit of red raspberry (#Rubus idaeus). Infection levels were unexpectedly high at the end of a relatively dry summer. Looks like #Phragmidium rubi-idaei. From Western Cape, ZA.

Privileged to have been part of the Wheat Rust Training team at Njoro, Kenya. Strong lecture component from international colleagues, appreciative trainees, and excellent field plots and greenhouse screening. @MaricelisAceve1 @SridharBhavani

#Blueberry (#Vaccinium sp.) #rust from Napier, Western Cape, ZA. Should be #Pucciniastrum minimum (= Thekopsora minima) according to a previous report.

#Rust caused by #Puccinia lagenophorae on Namaqua daisy (#Dimorphotheca sinuata), Kamieskroon, Northern Cape, ZA.

Pleased to announce our South African plant #rust image repository epidemiologiaufv.shinyapps.i… on the International Day of Plant Health 2024. Thanks Emerson Del Ponte @edelponte, Lisa Rothmann @LandbouLisa, and Willem Boshoff @B12272396Willem for reviving our photographs. #IDPH

#Rust on kikuyu grass (#Pennisetum clandestinum, syn. #Cenchrus clandestinus) caused by #Phakopsora apoda (syn. #Angiopsora apoda). Paraphyses are abundant and a hyperparasite fairly common. From Onrus River, Western Cape, ZA.

#Rust on #Dactylis glomerata collected at Golden Gate National Park, Free State, ZA. Thanks @LandbouLisa for spotting this.

#Puccinia oxalidis on #Oxalis latifolia (garden pink-sorrel) from Bloemfontein, South Africa.

#Rust caused by #Puccinia thaliae on #canna lily. Hypophyllous uredinia with water-soaked lesions on upper surface. From Onrus River, Western Cape, ZA.

#Stem rust of ryegrass (#Lolium) caused by #Puccinia graminis subsp. graminicola (Paarl, Western Cape, ZA). Mostly telia but a few urediniospores still present.

#Rye leaf rust (#Puccinia recondita) from Greytown, KwaZulu-Natal, ZA. Thanks Willem Boshoff for the sample.

Natural #wheat stem rust infection at a trial site in the Western Cape, South Africa. Looks like one of the triticale-attacking races according to the checks.

#Rust on black-jack (#Bidens pilosa). Doidge (1927) named it #Uromyces bidentis but other sources refer to #Uromyces bidenticola. No teliospores were found. From Greyton, Western Cape, ZA.

#Rust of sowthistle (#Sonchus) caused by #Miyagia pseudosphaeria (from Onrus River, Western Cape, ZA).