Efficacy of Azoxystrobin on Mycotoxins and Related Fungi in Italian Paddy Rice

Abstract

The efficacy of azoxystrobin was evaluated in the presence of mycotoxigenic fungi and relative mycotoxins in Italian paddy rice during the growing season in the field. Three experimental fields were considered and the applied experimental design was a strip plot with three replicates; rice samples were collected at four different growing stages. The efficacy of the fungicide treatment on rice fungal population was demonstrated with around 20% less total fungal incidence in sprayed samples compared to untreated ones; the same decrease was noted also in Fusarium spp. species but not in Aspergillus versicolor. Of the mycotoxins considered, ochratoxin A (OTA) and aflatoxins (AFBs) were never detected, deoxynivalenol (DON) was found in 46% of samples at levels always lower than 100 µg/kg, while sterigmatocystin (STC) occurred in all the paddy rice samples collected after flowering, with a maximum value of 15.5 µg/kg. Treatment with azoxystrobin was not effective in reducing DON contamination, but it had an important and significant effect on STC content, showing a decrease of 67% in the sprayed samples.

Monitoring Phenolic Compounds in Rice during the Growing Season in Relation to Fungal and Mycotoxin Contamination

“…Rice variety is relevant for fungal contamination, with Sole CL having the highest presence of fungi and CL26 the highest contamination with Aspergillus species (p ≤ 0.01) (Table 1). These data confirm results obtained in our previous studies where Sole CL was found to be the most contaminated rice variety and CL26 the most susceptible rice variety to A. versicolor infection [8,9]. 1).…”

“…Contamination by STC is low and not statistically different for the two years considered (Table 1). The rice variety showing the highest contamination by STC is Sole CL (Table 1), confirming data also found in our previous studies where this variety seemed to be more susceptible to STC accumulation [8,9] even if it showed a low Aspergillus spp. incidence.…”

“…1). In particular, considering also the results of previous studies [8,9], Penicillium spp. seem to be found sporadically and generally in low amounts on Italian paddy rice in field.…”

“…All the principal mycotoxin producing genera, such as Fusarium spp., Aspergillus spp. and Penicillium spp., have been found on Italian paddy rice, but only deoxynivalenol (DON) produced by F. graminearum, aflatoxins (AFs) produced by A. flavus and sterigmatocystin (STC) produced by A. versicolor were recently reported as Italian paddy rice contaminants [8,9]. Mycotoxins can be produced by fungal secondary metabolisms when favorable environmental and substrate conditions occur during the growing season and their presence in grains can impact human health.…”

A Long Road to Safer Food

“…The reduction of mycotoxin contamination can be obtained by intervening during the cultivation or storage of products. Research carried out by Giorni et al [ 8 ] tested the efficacy of the fungicide azoxystrobin on fungal parasites of rice and obtained a strong reduction (−67%) of sterigmatocystin while deoxynivalenol remained unaffected.…”