Sensitivity of Clonostachys rosea and Trichoderma spp. as Potential Biocontrol Agents to Pesticides

Abstract

Clonostachys rosea 47 (CR47), Trichoderma atroviride 59 (TA59), T. atroviride 312 (TA312), Trichoderma harzianum 24 (TH24), Trichoderma longibrachiatum 9 (TL9), T. longibrachiatum 144 (TL144) and Trichoderma viride 15 (TV15) were tested to evaluate their in vitro sensitivity towards five fungicides (carboxin, guazatine, prochloraz, thiram and triticonazole) and four herbicides (chlorsulfuron, chlorotoluron, flufenacet and pendimethalin). All antagonists showed low sensitivity to carboxin and thiram and high sensitivity to prochloraz. For mycelial radial growth, TV15 was highly sensitive to guazatine, prochloraz and triticonazole and TH24 moderately insensitive to carboxin, guazatine and thiram. For conidial germination TL144 was the most sensitive to the fungicides, for mycelial radial growth and conidial germination CR47 was the least sensitive. None of the antagonists showed any mycelial radial growth inhibition in presence of the herbicides at field dose, except for TL144. Most antagonists did not show any conidial germination inhibition by the herbicides. The in vitro toxicity of prochloraz, guazatine and triticonazole towards the antagonists was confirmed by light and scanning electron microscope showing hyphal disruptions and extrusion of cytoplasmic content. A mixture of CR47 and/or TA312 with carboxin, thiram and triticonazole, applied to wheat seeds, was able to control Fusarium culmorum artificially inoculated to wheat seedlings in growth chambers. In the field, the antagonists applied along with triticonazole or thiram, at 1/10 of the field dose to seeds naturally infected by F. culmorum, gave a disease control comparable to that induced by triticonazole at full field dose. Our results demonstrate how an integration of microorganisms with pesticides makes the control of wheat foot rot possible.

Biodegradation of fungicide Thiram (TMTD) in soil under laboratory conditions

“…Ekundayo (2002) found that Thiram depressed the fungal population by one order of magnitude. Roberti et al (2006) reported that mycelial growth and conidial germination of different Trichoderma species had a broad range of sensitivity to Thiram. Mohamed (2009) reported a fluctuating effect of herbicide Oxyfluorfen on soil fungal populations.…”

Sensitivity of four isolates of <i>Clonostachys rosea</i> to pesticides used in the strawberry crop in Brazil

“…C. rosea seems to be insensitive to herbicides, according to the results we obtained and the nding that the mycelial growth of isolate CR47 was stimulated in the presence of four herbicides applied at eld dose. 21) In eld experiments, weed control in the plot borders was achieved with glyphosate, and the e ciency of C. rosea in controlling strawberry gray mold was not reduced. 9) Under eld conditions, it is expected that there will be little contact between C. rosea and herbicides due to the main targets of herbicide (soil) and biocontrol agents (aerial plant parts).…”

“…14,[17][18][19][20] For instance, the isolate C47 of C. rosea was highly sensitive to prochloraz, slightly sensitive to carboxin and thiram, and insensitive to guazatine and triticonazole. 21) Fungi di er in their sensitivity to pesticides of the same chemical class or same mode of action, 16) and we cannot generalize regarding the sensitivity of a species to a pesticide. us, research on the sensitivity of biocontrol agents to pesticides is important.…”

Antagonistic Fungal Endophytes Colonizing Rhizome of Amomum centrocephalum A.D. Poulsen from North Sumatera, Indonesia

“…In another study, C.rosea was also reported to decrease the infection rate caused by Fusarium graminearum in soybean plant, showing a mycoparasitic habit (Pan et al, 2013). Integration of pesticide with C. rosea and Trichoderma spp were also reported to effectively control wheat foot rot caused by Fusarium cumorum [43].…”