How we cite our quotes:
It is fall, when thoughts turn
To love and death; the general thinks
Of his mother, how she died in the fall (lines 21-23)
This is the first appearance of Trujillo's mother in the poem, and she's immediately paired up with two gigantic concepts: love and death. This makes sense; Trujillo loves her and she has died. What this sets up, in a much larger sense, is the way in which both love and death will factor into Trujillo's rage, grief, and eventual genocidal actions.
Ever since the morning
his mother collapsed in the kitchen
while baking skull-shaped candies
for the Day of the Dead, the general
has hated sweets. (lines 36-40)
In this passage we learn how Trujillo's mother passed away. The important part here is the hatred that goes along with the death; instead of being sad, or grieving in any "standard" way, we only see that Trujillo's thoughts turn to hate. This is, as they say, telling.
He sees his mother's smile, the teeth
gnawed to arrowheads. (lines 52-53)
This passage comes right in the middle of a full stanza's worth of military violence and implications of slavery. Whoa there. Also, this line is a repeat of a similar line in the first part except, in the first bit, the Haitian children were gnawing their teeth, rather than Trujillo's mother doing so. The implication is that Trujillo's mother is very intimately connected with how Trujillo himself thinks through death and killing. And his justification for it, in some weird way, has to do with his grief over his mother.