Fumigation of agricultural products. XVI. —Some aspects of the fumigation of imported potatoes in boxes with methyl bromide for the control of tuber moth Gnorimoschema operculella (Zell.)

Abstract

As the phytotoxic action of methyl bromide on potato tubers is small a t the dosages which are lethal to all stages of the tuber moth, fumigation of potatoes against this insect is possible. Determination of residual fumigant, both free and fixed, and palatability tests, show that fumigation a t the dosages required is safe.Penetration of methyl bromide vapour in the boxes can be enhanced by taking advantage of the ' Turtle Effect '. *

CONTROL OF COLORADO POTATO BEETLE, LEPTINOTARSA DECEMLINEATA, IN SHIPMENTS OF HARVESTED POTATOES

“…of methyl bromide for a 4 h exposure at 25°C without injury (Table 11). Further data are needed to establish the importance of hardening-off in tolerance to methyl bromide; however, it is noteworthy that other tests on potatoes (Lubatti and Bunday 1958) have shown considerably greater tolerance than was observed here in the newly harvested, tender tubers. Although less injury was apparent at the surface 1 week after treatment, the final assessment made on the internal tissues at 2 weeks showed some injury at the 32 mg/l.…”

“…no appreciable difference was found between the Irish Cobbler and Superior potatoes and only slight damage began to show at this concentration at all three temperatures. Further data are needed to establish the importance of hardening-off in tolerance to methyl bromide; however, it is noteworthy that other tests on potatoes (Lubatti and Bunday 1958) have shown considerably greater tolerance than was observed here in the newly harvested, tender tubers.…”

“…Several other varieties have been found to be unaffected by fumigation with methyl bromide at dosages above these levels (Lubatti and Bunday 1958). for 4 h at 25°C with a 4 mg/l.…”

“…These dosages should not cause injury to potatoes, even when they are in the tender condition of the Irish Cobbler and Superior varieties tested here. Several other varieties have been found to be unaffected by fumigation with methyl bromide at dosages above these levels (Lubatti and Bunday 1958). As residual methyl bromide does not remain in fumigated potatoes for more than 24 h following treatment (Lubatti and Smith 1948) no residue problem would result from the treatment.…”