Microdochium Research Articles

The Effect of Sulfobetaine on the Activity of Strobilurins and Benzimidazole Fungicides

Surfactants (adjuvants) are the substances often added to the spray tank, besides the pesticide formulation, whose role is to improve the performance of the pesticide or the physical properties of the spray mixture, or both. Adjuvants are not often used as fungicides themselves, however, it is interesting to investigate if they can improve the fungistatic activity of the system they are included in. Therefore the main aim of this work was to determine the effect of the addition of a newly obtained, never investigated before, sulfobetaine type surfactant to the fungicides on their final properties. In the in vitro experiment fungistatic activity of the surfactant and the system of surfactant with strobilurins and benzimidazole fungicides were evaluated. The tested surfactants were added to the liquid medium of Potato Dextrose Agar (PDA) at concentrations: 1, 10, 50, and 100 ppm. The organisms of Fusarium culmorum, Rhizoctonia solani, Microdochium nivale, and Alternaria brassicas were used as indicators. The experiments have shown that the addition of the new surfactant studied to the medium resulted in inhibition of mycelium growth of all the tested fungi. The system with the surfactant and the fungicide was much more effective against the tested fungi than individual fungicides.

ANTAGONISTIC ACTIVITY OF FUNGI FROM ANTHRACNOSE LESIONS ON PAULLINIA CUPANA AGAINST COLLETOTRICHUM sp.

Anthracnose is a cosmopolitan disease caused by Colletotrichum spp. that affects many crops worldwide. Observations have shown that anthracnose leaf lesions may be colonized by several non-pathogenic microorganisms. The relationship of these microorganisms with the pathogen as well as their potential as biocontrol agents is not well known. Guarana (Paullinia cupana Mart. var. sorbilis) is a typical native Amazon crop with unknown microbial diversity. Guarana productivity has been reduced by a fungal disease caused by Colletotrichum sp. In this study, we isolated 15 fungi from guarana anthracnose leaf lesions that belong to five genera: Fusarium, Phomopsis, Leptosphaeria, Microdochium and Pestalotiopsis. Four isolates from the Fusarium sp. (C6 and C10), Pestalotiopsis sp. (C3), and Microdochium sp. (P7) consistently inhibited anthracnose fungal growth in vitro. Except for the Microdochium sp. (P7), these isolates were also able to inhibit the growth of the pathogen in in vivo assays using detached guarana leaves. Some mechanisms related to the growth inhibition of this pathogen were studied. Fusarium sp. (C6) produced chitinases; Fusarium sp. (C6, C10) and Pestalotiopsis sp. (C3) produced antagonistic volatile organic compounds. These three isolates also inhibited the growth of Fusarium spp., a pathogen of several plant species, suggesting their potential broad range of growth inhibition of other phytopathogens.

Survey of the main causal agents of fusarium head blight of durum wheat around Bologna, northern Italy

Several Fusarium species and Microdochium nivale are involved in fusarium head blight (FHB), which in Italy has been constantly present on wheat since 1995. This study was carried out from 1995 to 2007 on FHB-infected durum wheat heads collected in the Bologna countryside, Emilia-Romagna, northern Italy. The most frequent Fusarium species found were: Fusarium graminearum (32.1%), F. culmorum (25.2%) and F. poae (17.8%), while F. avenaceum and M. nivale occurred discontinuously. Other Fusarium species were also found, but only sporadically. It is important to identify and characterize the main species involved in the FHB syndrome for this will help us to establish control strategies that will contain the disease and the content of mycotoxins in food and animal feed.