Anna Maria Menniti

Effect of Fungicides on Fusarium Head Blight and Deoxynivalenol Content in Durum Wheat Grain

In 1998–99 and 1999–2000 six trials were conducted to evaluate the effect of fungicides on Fusarium head blight in the field, on infected kernels and deoxynivalenol (DON) concentration in grain. A single application of prochloraz, tebuconazole, epoxiconazole or bromuconazole, applied to durum wheat varieties at the manufacturers recommended dose at the beginning of anthesis stage, provided good control of the disease when infective pressure in the field was low to medium, and when the main pathogens were F. graminearum and F. culmorum. Kresoxim-methyl showed a low efficacy at controlling the disease. Tebuconazole, prochloraz and bromuconazole were effective at controlling F. graminearum and F. culmorum, while kresoxim-methyl was not effective in reducing Fusarium infected kernels. DON concentration in grain of cultivars inoculated with F. graminearum and F. culmorum was high, averaging 4.2 mg kg−1 (untreated control). Tebuconazole, prochloraz and bromuconazole reduced DON concentration by 43%, while epoxiconazole was ineffective. DON concentration in kernels of naturally infected cultivars was 1.95 mg kg−1, a concentration which exceeds the 1 mg kg−1 maximum level of contamination allowed in the United States. Furthermore prochloraz, bromuconazole and tebuconazole applications, in the naturally inoculated trials, reduced DON concentration from 73% to 96%, while epoxiconazole showed the lowest effectiveness. Moreover, a positive linear correlation between Fusarium infected grains and the DON concentration was observed.

Activity of natural compounds on Fusarium verticillioides and fumonisin production in stored maize kernels.

The ability of trans-2-hexenal, carvacrol and eugenol to control F. verticillioides was explored in vitro and in artificially infected kernels. The effect of the trans-2-hexenal fumigation on F. verticillioides control, fumonisin production and kernel germination was also investigated in naturally infected kernels. Trans-2-hexenal, carvacrol and eugenol vapour showed fungicidal activity against F. verticillioides, in in vitro trials. Trans-2-hexenal was the best pathogen inhibitor, followed by carvacrol and eugenol. In maize kernels, fumigations with trans-2-hexenal provided a high inhibitory effect on F. verticillioides growth and its efficacy depended on concentration and time of incubation. The most effective dose of trans-2-hexenal was 369 microL/L, but this concentration induced off-odour in maize. The exposure to 246 microL/L trans-2-hexenal provided the best control of F. verticillioides and no phytotoxic symptoms or off-odour in kernels was observed. In contrast trans-2-hexenal fumigations were ineffective in the reduction of fumonisin concentration and high concentration (369 microL/L) stimulated fumonisin levels. Reduction or delay in the germinability of the kernel was observed after trans-2-hexenal exposure. The results showed that trans-2-hexenal postharvest fumigation is effective in F. verticillioides control also in asymptomatic maize kernels, but cannot reduce fumonisin production.

Activity of trans‐2‐hexenal against Penicillium expansum in ‘Conference’ pears

Aims:  To investigate the effects of trans‐2‐hexenal on blue mould disease, patulin content and fruit quality in ‘Conference’ pears.

Some factors influencing patulin production by Penicillium expansum in pome fruits.

BACKGROUND The objective of our study was to examine the effects of Penicillium expansum on patulin production in relation to isolates, species and cultivar type, incidence and severity of decay. In addition, patulin production at different incubation times and its diffusion were also investigated. These factors were evaluated in pome fruits inoculated with P. expansum and kept at 20 °C for short periods of time. RESULTS The ability of five P. expansum isolates to grow and produce patulin in inoculated Golden Delicious apples varied among the strains from below the limit of quantification to 662 µg kg(-1). Variety and species of pome fruits influenced patulin production. P. expansum isolate PE97.IT produced a higher patulin content in apples than in pears. The highest patulin production was 386 µg kg(-1) in Golden Delicious. No blue mould symptom appeared in pears inoculated with P. expansum and no patulin was detected after 3 days at 20 °C. However, patulin increased with incubation time after 6 and 8 days. No patulin was detected in healthy pear tissue but it was high in the decayed area. CONCLUSION Since patulin production is associated primarily with infected rotten tissue, patulin control is possible by using healthy fruits, sorting damaged and rotten fruits before processing.

Physio-pathological responses of cabbage stored under controlled atmospheres

Abstract The response of cabbage to controlled atmospheres (CA) of 1–3% O2 and 1–10% CO2; 3% O2 and 5% CO2 was studied in relation to the incidence of physiological and pathological disorders. Fungal infections, pepper spot, low oxygen injury, weight loss, colour, odour, flavour and ethanol were evaluated. The findings show that CA did not reduce Botrytis cinerea rot in comparison to low temperature storage in air. PVC film and CA, on the other hand, reduced pepper spot by over 50% with respect to the air control. In particular, pepper spot was eliminated by high CO2 (10%) levels. Low O2 (1% O2 and 1% CO2) atmospheres caused 33 and 50% injury respectively after 89 and 109 days of storage. CA and PVC film reduced weight loss to 1%, as compared with 11% in the heads in air, which had shrivelled. The combination of 3% O 2 5% CO 2 and PVC film delayed yellowing with respect to air control. Concentrations of 1–3% O2 and 10% CO2 resulted in off odours and flavours after 74 days of storage. This result was confirmed by a considerable increase in ethanol concentrations. The most effective concentration tested was 3%O 2 5%CO 2 although, in general, infection by B. cinerea limited the storage life.