Hanson Sanford (sailorpeak05)

Maize [Zea mays L.] is an important food and feed crops in northeast of China. In 2019, maize seedling blight with an incidence of up to 25% was found at the field in Fushun city of Liaoning Province. Typical symptoms of seedlings were yellow, thin, wilt and die. The leaves gradually became yellow from the base of the plant to the top. Root system was poorly developed. The primary roots were usually discolored and rotted. And faintly pink or puce-coloured mould was found on seeds of the rotted seedings. Symptomatic roots of diseased seedling were collected and surface-disinfested with 70% ethanol for 1 min and then in 2% NaClO for 3 min, rinsed with sterilized water three times, cut into small pieces and placed on potato dextrose agar (PDA) medium for 5 days at 25 °C. Colonies on PDA were pink to dark red with fluffy aerial mycelium and red to aubergine pigmentation with the age. The causal agent was transferred to carnation leaf agar (CLA) medium and incubated at 25°C under a 12-h light-dark cycle. 12 Pure cplants and was identical to the original isolate. The experiment was repeated once with similar results. To our knowledge, this is the first report of seedling blight caused by F. asiaticum on maize in northeast China, and it has posed a threat to maize production of China. References Leslie J F and Summerell BA. 2006. The Fusarium laboratory manual. Blackwell Publishing, Ames, pp 176-179. O'Donnell et al.2004. Fungal Genetics and Biology 41 600-623. O' Donnell et al. 2015. Phytoparasitica 43583-595. White T J et al. 1990. Academic Press, San Diego, CA, pp 315-322. Chandler E A et al. 2003. Physiological and Molecular Plant Pathology 62(6) 355-367.White leaf spot (Neopseudocercosporella capsellae) is a persistent and increasingly important foliar disease for canola (Brassica napus) across southern Australia. To define the role of plant growth stage in the development of disease epidemics, we first investigated the response of different canola cultivars (Scoop and Charlton) at five Sylvester-Bradley growth stages against N. capsellae. White leaf spot disease incidence and severity was dependent on plant growth stage and cultivar (both P less then 0.001), with plants being most susceptible at plant growth stage 1.00 (cotyledon stage) followed by plant growth stage 1.04 (fourth leaf stage). Then, to quantify the impact of this disease on canola yield, we investigated the in-field relationship of white leaf spot disease incidence and severity with seed yield loss following artificial inoculation commencing at growth stage 1.04 (fourth leaf stage). White leaf spot significantly (P less then 0.001) reduced seed yield by 24% in N. capsellae inoculated field plots compared with noninoculated field plots. To our knowledge, this is the first time that serious seed yield losses from this disease have been quantified in the field. The current study demonstrates that N. capsellae disease incidence and severity on canola is determined by host growth stage at which pathogen infestation occurs. Emerging seedling cotyledons were highly susceptible, followed by less susceptibility in first true leaves to emerge, but then increasing susceptibility as plants subsequently aged toward the fourth leaf stage. This explains field observances where white leaf spot readily establishes on emerging seedlings and subsequently becomes more prevalent and severe as plants age.Aphelenchoides besseyi is the causal agent of soybean green stem and foliar retention syndrome known as "Soja Louca II." This nematode has recently been reported parasitizing cotton in Brazil. In Costa Rica, it causes the symptoms known as "amachamiento" and false angular spots in common bean (Phaseolus vulgaris). Due to the great importance of beans to Brazilian agriculture, the objective of this research was to study the pathogenicity of A. besseyi in common bean under greenhouse conditions, including its endoparasitic relationships by staining root and shoot system tissues with