30 Pork News & Views Better Pork April 2021 Pork News & Views Ontario Ministry of Agriculture, Food and Rural Affairs Better Pork | December 2023 Methods From October 2 to October 5, 2023, 192 ear corn samples were collected from across the province. Five consecutive ears were collected from four random locations (20 ears total) throughout a field and placed into high temperature driers (80°C) as soon as possible after collection. Pictures were taken to document moulds, insect/ bird feeding damage and any other disorders (Fig. 1). Dry ears were shelled and coarse ground and mixed for sub-sampling consistency. Sub samples were collected and finely ground for DON analysis by quantitative ELISA analysis at the University of Guelph Ridgetown Campus mycotoxin lab. Results Results for the 2023 survey are presented in Table 1. While there were many clean samples, more samples than normal displayed some background level of ear mould. DON concentrations were higher than long term survey averages. There also appeared to be a slightly greater incidence of insect feeding damage in the 2023 survey. As is usual in a year conducive for ear mould establishment and growth, these samples were associated with greater visual ear moulds. Many mouldy samples had no ear damage however, suggesting weather and hybrid susceptibility were still primary factors for fungal infection. Distribution of samples and their corresponding DON levels are presented in Figure 2. Even with 77% of 2023 samples testing below 2 ppm, growers should be vigilant, as they may have fields with elevated DON. Fields should be evaluated for risk and consider harvesting and drying higher risk fields before infections worsen. Understand management and storage options for corn with higher DON concentrations (see “Going Forward” below). Ear moulds and mycotoxins occur every year in Ontario and fields need to be assessed individually. Growing season Planting was slightly delayed as lingering rains and cooler weather limited soil drying through early May. Once conditions were fit, planting progressed rapidly (~ 2nd and 3rd week of May for many areas). Weather generally remained sunny and dry through planting. Except for the odd rain event, sunny, hot and dry conditions dominated through to later June. Starting the last week of June, general instability took over and rainfall events started across many areas. Frequent rainfall events and thunderstorms continued through July. Some of the earliest fields started tasseling the third week of July, though the last week of July and first week of August appeared to be the peak for pollination across large parts of the province. Frequent rainfall continued through August and into early September for many areas. Corn canopies remained wet for long periods even when it wasn’t raining. Wet conditions at silking are very favourable for ear mould establishment while wet conditions through grain fill allow continued development. With lower-than-normal heat unit accumulation in 2023, the corn crop is less mature and higher moisture than normal in many cases. This can be a risk for contiDON Concentration parts per million (ppm) All Samples* Total Samples 192 < 0.50 ppm 41% 0.50 to <2.00 ppm 36% 2.00 to <5.00 ppm 18% 5.00 ppm and greater 5% Table 1: Deoxynivalenol (DON) results from the 2023 Ontario grain corn ear mould and DON survey. *percentages may not sum to 100 due to rounding Figure 1: Some common corn ear moulds which can be observed in Ontario
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