Field evaluation of vaporised ethyl formate and carbon dioxide for fumigation of stored wheat.
BACKGROUND
Vapormate is a cylinderised non-flammable mixture of ethyl formate (16.7% by weight) and carbon dioxide (CO(2)) that has been developed as a rapid fumigant of stored grain. Four field trials were undertaken on wheat in 50 t farm silos to demonstrate the feasibility of dynamic application. To assess treatment efficacy, each trial tested mixed stages of Rhyzopertha dominica F. (>11,000), Tribolium castaneum (Herbst.) (>1500) and Sitophilus oryzae (L.) (>13,000) in mesh cages positioned through the centre of the grain bulk and on the grain surface. Ethyl formate and CO(2) concentrations were measured in the silo during fumigation and in ambient air outside the 6 m fumigation zone. Application rates of 420, 660 and 940 g m(-3) of ethyl formate/CO(2) formulation and exposure times of 24, 3 and 72 h, respectively, were examined using wheat of 10.4-11.7% moisture content and grain temperatures between 2 and 32 degrees C.


RESULTS
All life stages of R. dominica and T. castaneum were fully controlled under all conditions tested, and mortality of all life stages of S. oryzae was greater than 98%.


CONCLUSIONS
Dynamic application of vaporised ethyl formate and CO(2) to 50 t silos proved safe to operators and rapidly effective against stored-grain insects on cold to warm grain.
Dojchinov
Greg
G
CSIRO Entomology, Canberra, ACT 2601, Australia.
Damcevski
Katherine A
KA
Woodman
James D
JD
Haritos
Victoria S
VS
D000818:Animals; D001681:Biological Assay; D002245:Carbon Dioxide / Q000009:adverse effects / Q000032:analysis / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D005511:Food Handling / Q000379:methods*; D005563:Formic Acid Esters / Q000009:adverse effects / Q000032:analysis / Q000737:chemistry*; D005651:Fumigation / Q000009:adverse effects / Q000379:methods*; D007300:Insect Control / Q000379:methods*; D016272:Occupational Health; D013232:Steel; D013997:Time Factors; D014908:Triticum; D014835:Volatilization
D005563:Formic Acid Esters; C510888:ethyl formate; D013232:Steel; D002245:Carbon Dioxide