The potential efficiency of irrigation management and propargyl bromide in controlling three soil pests: Tylenchulus semipenetrans, Fusarium oxysporum and Echinochloa crus‐galli

Abstract

Propargyl bromide (3-bromopropyne, 3BP) is a potential alternative for methyl bromide. Little information is available about its efficiency in controlling pests. The purpose of this paper is to estimate the 3BP dose required for killing three pests and to compare the efficiency of water management approaches to that of fumigation. The pests, Fusarium oxysporum Schlecht (fungus), Echinochloa crus-galli (L) Beauv (grass) and Tylenchulus semipenetrans Cobb (nematode) were exposed to different 3BP concentrations in a sandy loam at 30 degrees C in a closed system. The lethal dose for killing 90% of the population (LD90) was calculated from the total applied mass, and varied from 0.3 microg g(-1) soil for the nematode, 3 microg g(-1) for the grass, and 9 microg g(-1) for the fungus. The concentration-time index for killing 90% of the population (CT90) was 11 microg g(-1) h for the nematode, 112 microg g(-1) h for the grass and 345 microg g(-1) h for the fungus. 3BP seems as efficient as other fumigant alternatives in controlling these pests. Using an open system, it was shown that the volume of soil in which the pests were controlled varied for different irrigation managements. Even 96 h after fumigation (with a concentration 10 times higher than would potentially be applied in the field), more than 20% of the soil volume had not reached the fungus and grass CT90 of the non-irrigated soil. The soil underneath the furrow and the bed reached CT90 only slowly in all irrigated treatments even though techniques for increasing efficiency were used (tarping, surface sealing with water and high application rate).

Evaluation of Propargyl Bromide as a Soil Fumigant

“…We also found that field bindweed and cheeseweed were not completely controlled even at the highest rate of propargyl bromide: 168 kgÁha -1 . In another laboratory study, the relative order of sensitivity of soil-borne organisms to propargyl bromide demonstrated that the citrus nematode was the most sensitive, followed by barnyardgrass then F. oxysporum (Allaire et al, 2005). In our field study, citrus nematode and F. oxysporum were always more sensitive to propargyl bromide compared with the weed species tested.…”

“…Propargyl bromide is one of many compounds being considered as a methyl bromide alternative (Allaire et al, 2005;Ma et al, 2001;Schneider et al, 2006). In 1957, Dow Chemical Company was granted a patent for propargyl bromide as a soil fumigant.…”

Weed control with methyl bromide alternatives.

“…This material currently is used in the synthesis of industrial and agrochemical organic compounds [47]. Recent laboratory tests have suggested that more stable formulations of propargyl bromide may have potential as a MeBr alternative [48] with dose-dependent effects on nematodes, fungi, and some weeds; including barnyardgrass [49,50]. The efficacy of propargyl bromide is strongly influenced by soil type, presumably as a result of rapid degradation under high organic matter conditions [50].…”