Rashi: The wine barrels will get moldy. Radak - Avshu is like Ipshu. Beis and Pei are interchangeable, for they are pronounced from the same place (the lips). A Mishnah (Pe'ah 6:1) says 'Hevker l'Aniyim' in place of Hefker.

Radak: Ferudos are seeds underground. This is another curse - the seeds will be ruined and moldy under the ground, and not sprout. What does sprout, locusts will eat it. Or the seeds will become moldy due to rain that does not fall on them. Rain will be withheld in these years.

Radak citing Targum Yonasan: The barrels of wine melted under their corks.

Malbim: The collections of grain buried in the ground in separate piles, also they became moldy. The locusts could not get to them.

Rashi citing Targum Yonasan: The corks that cover the barrels.

Radak: They are clumps of earth. This is like "b'Even Oh b'Egrof" (Shemos 21:18) according to some Meforshim.

Rashi: Those of wine and oil.

Radak: They are of grain. They are desolate, for there is nothing to put in them.

Rashi: They are storehouses of grain. Radak - this is like "ha'Od Zera ba'Megurah" (Chagai 2:19). The matter is repeated in different words.

Malbim: They are smaller [storehouses] than Otzeros.

Radak #1: It is as if they are destroyed, for no one enters anything in them.

Radak #2: They are destroyed because no one is concerned to fix them, like people normally do each year. They fall and are destroyed.

Radak: [Also] the first Mem is added; the letters Aleph, Mem, Tov, Yud and Nun are sometimes added [at the beginning] of a word. (Also the second Mem is added; it is not part of the root.) We find words with two added letters, e.g. Matla'ah (weariness, from the root La'ah).

Radak citing his father: The first Mem is a prefix, as if there were a Chirik under it; some of the storehouses were destroyed. It has a Patach, like "lemaba'Rishonah" (Divrei ha'Yamim I, 15:13), "Lo Hiskadeshu lema'Dai" (Divrei ha'Yamim II, 30:3).

Malbim: Via this, the storehouses were destroyed.