25 Heb “it.” Throughout vv. 6–7 the Hebrew uses singular forms to describe the locust swarm, but the translation uses plural forms because several details of the text make more sense in English as if they are describing the appearance and effects of individual locusts.
26 Heb “my.”
27 Both “vines” and “fig trees” are singular in the Hebrew text, but are regarded as collective singulars.
28 Heb “my.”
29 Heb “it has completely stripped her.”
30 Heb “her.”
31 Heb “grow white.” Once choice leafy vegetation is no longer available to them, locusts have been known to consume the bark of small tree limbs, leaving them in an exposed and vulnerable condition. It is apparently this whitened condition of limbs that Joel is referring to here.

In other versions

It has laid waste my vine

and splintered my fig tree;

it has stripped off their bark and thrown it down;

their branches are made white.

It has laid waste my vines

and ruined my fig trees.

It has stripped off their bark

and thrown it away,

leaving their branches white.

It has devastated my grapevine

and splintered my fig tree.

It has stripped off its bark and thrown it away;

its branches have turned white.

It has destroyed my grapevines

and ruined my fig trees,

stripping their bark and destroying it,

leaving the branches white and bare.

It has made my vine a desolation,

and my fig tree a completely splintered stump.

It has stripped them bare and thrown them down;

their branches have turned white.

He hath laid my vine waste,

And barked my fig tree:

He hath made it clean bare, and cast it away;

The branches thereof are made white.

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