New lab methods for speed testing of fumigant emissions
A simpler, quicker way to track pesticide emissions from agricultural fields has been devised by the United States Agricultural Research Service (ARS) scientists. Using low-cost laboratory tests and mathematical models, research leader Dr. Scott Yates and colleagues at the United States Salinity Laboratory in California are able to evaluate – and even predict – fumigant emissions.


Each potential methyl bromide replacement will require its own set of regulations, based on findings from complex field studies that may number as many as 60. Such studies can take up to a year to complete and very expensive, besides exposing researchers to toxic chemicals. Dr. Yates’ team has shown that lab tests can yield some of the same results as those painstakingly obtained from outdoor field studies. To collect their data, the ARS scientists designed elaborate soil columns and soil cell equipment with which to observe pesticide movement through soil. They combine data collected this way with numerous mathematically driven models. Dr. Yates admits that field studies will always be needed to tie lab-based findings to the real-world agricultural landscapes.


Source: www.ars.usda.gov
New fumigant to secure grains
In Australia, a partnership between CSIRO and the Grains Research & Development Corporation (GRDC) is setting up alternatives to phosphine fumigation and chemicals facing environmental phase-outs. Phosphine has been the mainstay of insect control in stored grain and an important factor in Australia’s reputation for clean grain in export markets. However, in Australia pressure has been on to find a new fumigant, as increasing numbers of insects show signs of phosphine resistance. Most alternatives have been discarded because of environmental issues, such as residues or ozone-depleting characteristics.


Over the past 10-15 years, CSIRO Entomology Department has carried out several successful GRDC projects investigating fumigant alternatives. So far, the most promising has been GLO2, which contains 95 per cent ethyl formate and five per cent isothiocyanide, both of which are naturally occurring chemicals. GLO2 has been formulated as a liquid fumigant for directly spraying onto grains. It will vaporize in situ, but can also be vaporized prior to use if required. “A big advantage is that it is quick – GLO2 takes less than a day to fumigate and there is no withholding period,” the researchers say. It can be used to fumigate bulk stores, replacing methyl bromide, and for structural and equipment fumigation, replacing dichlorvos. It could also be used as part of a phosphine-resistance management strategy.


Although laboratory tests, on-farm trials and 50-tonne silo trials have already proven the product’s ability, the team must now focus on providing data to support an application for product registration.


CSIRO is undertaking regionally based storage trials with all grain types to understand GLO2’s toxicology, so that label rates, environmental effects, efficacy and health and safety issues can be determined. GLO2’s advantages include:
 
  • Shows a high level of efficacy in eradicating major grain pests at all life stages;
     
  • Acts quickly and leaves virtually no residue;
     
  • Does not affect grain quality;
     
  • Breaks down to compounds that occur naturally in grains;
     
  • Is a liquid that is safe and simple to use in comparison to other fumigants and pesticides;
     
  • Has component compounds that are already in use as fumigants and food additives; and
     
  • Does not affect the ozone layer or contribute to greenhouse gases.
     

Source: www.grdc.com.au