Mycorrhizal growth in pure cultures in the presence of pesticides

Abstract

The effects of pesticides on 64 ectomycorrhizal fungi of boreal forest trees were studied in vitro. The pesticides (fungicides: benomyl, chlorothalonil, copper oxychloride, maneb and propiconazole; herbicides: chlorthiamid, glyphosate, hexazinone, linuron and terbuthylazine; insecticide: cypermethrin) were selected as those commonly used in Nordic forest nurseries and afforestation sites. In general, the fungicides proved to be more toxic to ectomycorrhizal fungi than the herbicides and cypermethrin. The fungicides, chlorothalonil and propiconazole, had the clearest inhibitory effect on growth of mycorrhizal fungi. Conversely, maneb, glyphosate and terbuthylazine stimulated the growth of some mycorrhizal fungi. Leccinum versipelle and L. scabrum, Paxillus involutus and Cenococcum geophilum were the most sensitive ectomycorrhizal fungi to the various pesticides.

Evaluation of some fungicides on mycorrhizal symbiosis between two Glomus species from commercial inocula and Allium porrum L. seedlings

“…In foliar application, Chlorothalonil has been used in a number of experiments, where its effectiveness in reducing the abundance of AM fungi was demonstrated (Aziz et al, 1991;Wan et al, 1998;Laatikainen and Heinonen-Tanski, 2002). These reports are in contrast with the observations made in this study because this active ingredient did not affect the AM fungi.…”

Annual growth rings and the impact of Benlate 50 DF fungicide on citrus trees in seasonally dry tropical plantations of northern Costa Rica

“…Our results demonstrate that Benlate 50 DF treated citrus tree grew slower for the first 6 years of their life, after which radial grow became similar to that recorded in the untreated trees. Benlate 50 DF breaks down into di-butyl urea, which can inhibit photosynthesis and be toxic to mycorrhizal fungi associations on plant roots (Shilling et al, 1994;van Iersel and Bugbee, 1997;Laatikainen and Heinonen-Tanski, 2002). This study demonstrates the usefulness of using dendrochronological techniques to examine growth rates in an important economic fruit tree species receiving different cultural treatments.…”

“…Annual precipitation for TicoFrut plantations near Boca Arenal(1992- 1998) and Los Chiles (1997-2002 in north-central Costa Rica.…”

Testing the effect of routine fungicide application on ectomycorrhiza formation on Pinus halepensis seedlings in a nursery

“…This may be due to a negative effect of the fungicides on the development of mycorrhizal symbiosis and ⁄ or on the growth of fungal mycelium, as seen in studies conducted under in vitro conditions (Zambonelli and Iotti 2001;Laatikainen and Heinonen-Tanski 2002;Díaz et al 2003). In the study by Díaz et al (2003), Pisolithus tinctorius 3SR was the most sensitive in terms of mycelial growth whereas Pisolithus tinctorius Mx was the most resistant.…”