The influence of alachlor, trifluralin, and diazinon on the development of endogenous mycorrhizae in soybeans

Abstract

Preplant incorporated treatments of 2 and 4 kg/ha of trifluralin and diazinon had no significant effect on growth, P accumulation or root colonization by mycorrhizal fungi in soybeans planted in an Andover clay loam. At 4 kg/ha, alachlor and trifluralin inhibited root development of 25 day-old plants. The 4 kg/ha alachlor treatment reduced shoot weight of 25 day old plants significantly and suppressed mycorrhizal development of 25 to 60 day old plants. At currently used commercial rates neither alachlor, trifluralin, nor diazinon affected mycorrhizal development under the conditions of the experiment.

Effect of cyanazine herbicide on VA mycorrhizal infection and growth ofPisum sativum

“…For example, no effect (Burpee and Cole, 1978) or nega-tive effect (Pellet and Sieverding, 1986) of Alachlor and Trifluralin on VA mycorrhizas has been observed. The use of sand/vermiculite medium may be suitable to test the effect of herbicides on VA mycorrhizas because less variables must be considered.…”

Effect of Agrochemicals on Mycorrhizae

“…Organophosphate insecticides and nematicides like chlofenviphos, carbaryl, diazinon, ethoprop, malathione and parathion generally have no effect, or a slightly detrimental effet on MI (Backman and Clark, 1977;Burpee and Cole, 1978;Parvathi et al, 1985b;Spokes et al, 1981). The carbamate insecticides aldicarb, carbofuran and oxamyl are reported to have no effect, detrimental effects or beneficial effects on mycorrhizae (Nemec, 1985;Ocampo and Rayaman, 1980;Spokes etal., 1981).…”

“…This is ofparticular significance because AMF occur in a large number ofcommercial crops, and the wide use oftoxic materials in normal agricultural practices may therefore upset this balance. Burpee and Cole (1978) and Smith (1978) have assessed changes in the percentages of infected roots and spore production. Thus, any observed changes result from the response ofeach ofthe three preceding stages as well as the stage in which chemicals are added.…”

The effects of fungicide‐coated seeds on the establishment of VA mycorrhizal infection

“…For example, infection of onions by VA mycorrhizal fungi in soil treated with aldicarb (which is also a nematicide) was similar to that of the untreated controls, whereas chlorfenvinphos delayed infection (Spokes, Macdonald & Hayman, 1981). Carbofuran, (Backman & Clark, 1977) and parathion (Parvathi, Venkateswarlu & Rao, 1985) decreased the formation of VA mycorrhizas but diazinon (Burpee & Cole, 1978) did not. Carbaryl and endosulphan at 5 mg/litre had little effect except for delaying infection (Parvathi et al, 1985).…”

“…These effects vary. Soil fumigants such as methyl bromide are toxic (Kleinschmidt & Gerdemann, 1972;Bird, Rich & Glover, 1974), whereas herbicides appear to have little effect (Burpee & Cole, 1978;South, 1981;Nemec & Tucker, 1983), although paraquat and simazine had an adverse effect on Glomus etunicatum (Nemec & Tucker, 1983). Insecticides have a range of effects on VA mycorrhiza.…”