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ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Commodity Protection and Quality Research » Research » Publications at this Location » Publication #168270
Title: METHYL IODIDE AND FORCED AERATION ON THE POSTHARVEST QUALITY OF LEMONS

Author
item Aung, Louis
item Leesch, James
item Jenner, Joel

Submitted to: Postharvest Biology and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/13/2004
Publication Date: 3/13/2004
Citation: Aung, L.H., Leesch, J.G., Jenner, J.F. 2004. Methyl iodide and forced aeration on the postharvest quality of lemons. Postharvest Biology and Technology 33(2004):45-50

Interpretive Summary: With the pending loss of methyl bromide as a fumigant, several new fumigants are being researched for their ability to replace methyl bromide. The fumigation of lemons to kill California red scale using methyl iodide is one promising alternative. Methyl iodide, however, may cause some phytotoxicity on lemons and this study was initiated to determine if the time of forced aeration following treatment could alleviate such phytotoxic effects. The study showed that when the aeration of the methyl iodide following fumigation was 24 hours, the phytotoxicity was indeed eliminated. Lemons from different locations and ripening periods were tested and the increased aeration eliminated the phytotoxicity evident following just 2 hours of aeration.

Technical Abstract: Methyl iodide (MI) fumigation to control California red scale (Aonidiella aurantii) at dosages of 24, 28 and 32 g/m(3) for 2h combined with 2- and 24-h forced aeration using 3.51 of air per min at 21EC immediately after fumigation was tested on early-, mid- and late-season lemons [Citrus limon (L.) Burm. F] from the coastal and desert regions. The MI treatment lowered fruit quality due to moderate to severe rind injury with increasing MI dosage. The degree of lemon phytotoxicity was influenced by season of harvest. Early season lemons of both coastal (cooler) and desert (warmer) regions sustained less fruit phytotoxicity than mid- and late-season lemons. Forced aeration of 24-h immediately after the MI treatment dramatically reduced fruit phytotoxicity irregardless of seasonal and climatic factors. Based upon the results of MI and on the known response of California red scale to this fumigant, we propose that a MI dosage of 26 g/m(3) for 2 h combined with a 24-h forced aeration post-fumigation could provide an effective quarantine treatment for lemon.