The Effect of Foliar Fungicide and Insecticide Application on the Contamination of Fumonisins, Moniliformin and Deoxynivalenol in Maize Used for Food Purposes.

The fungal ear rot of maize cultivated in temperate areas is mainly due to the Fusarium species. The use of insecticides against European Corn Borer (ECB) reduces the severity of fungal ear rot as well as the fumonisin (FB) and moniliformin (MON) levels in maize kernels at harvest, which in turn results in a lowering of their effect on deoxynivalenol (DON) control. However, the direct fungicidal control of ear rot has rarely been implemented for maize, and the first studies reported conflicting results on the reduction of mycotoxins. In the present experiment, field trials were carried out in North Italy over three growing seasons to study the effect of fungicide application timings on maize to control mycotoxins, considering the interaction of the application with the insecticide treatment, according to a full factorial split plot design. The mycotoxin content was determined through LC-MS/MS analysis. The field trials showed a significant reduction in ECB severity (75%), fungal ear rot severity (68%), Fusarium Liseola section infection (46%), FBs (75%) and MON (79%) as a result of the insecticide application for all the years, while the DON content increased by 60%. On the other hand, a fungicide application alone or applied in plots protected by an insecticide was never effective for the fungal symptoms, infection or mycotoxin content. The results confirm that a correct insecticide application to control ECB damage is the most effective agrochemical solution for the control of fungal ear rot, FBs and MON.

Application of Fungicides and Microalgal Phenolic Extracts for the Direct Control of Fumonisin Contamination in Maize.

Fungicides and, for the first time, microalgal phenolic extracts (MPE) from Spirulina sp. and Nannochloropsis sp. were applied on maize culture media under field conditions to evaluate their ability to minimize Fusarium species development and fumonisin production. An in vitro assay against F. verticillioides was carried out using maize grains as the culture medium. An open-field experiment was carried out in Northwest Italy under natural infection conditions. The compared treatments were factorial combinations of two insecticide treatments (an untreated control and pyrethroid, used against European Corn Borer), four antifungal treatments (an untreated control, MPE from Spirulina sp., MPE from Nannochloropsis sp., and a synthetic fungicide), and two timings of the application of the antifungal compounds (at maize flowering and at the milk stage). The MPE compounds were capable of inhibiting fumonisin production in vitro more efficiently than tebuconazole. Insecticide application reduced the infection by Fusarium species and subsequent fumonisin contamination. However, fumonisins in maize fields were not significantly controlled by either fungicide or MPE application.