Today in the orchard
Neem oil on young apple tree
We have begun to apply Neem oil to all the young apple trees (less than ten years old) in the orchards. In late June/early July we paint the oil at full strength to the trunks up to about knee-high. We do this to combat the round-headed apple tree borer (Saperda candida), possibly the worst pest in the young orchards of Maine. The borer lays an egg that hatches into a larvae that tunnels through the trunk causing the tree to weaken and then break off. Eventually the mature beetle emerges from the tunneled trunk and heads off to kill more trees.
Although we don’t know how neem works, we suspect that the oil smothers the eggs or the smell deters the beetle from laying the eggs in the first place. We apply neem in late June because it coincides with egg-laying period. We’ve painted the trunks earlier in June which is less effective. This year we found only one borer so far in 400+ trees. In an untreated orchard in central Maine, you might find hundreds. Neem works.
Neem trees (Azadirachta indica) can be found throughout South Asia. The pungent oil is extracted from the seed kernels and has been used as an organic pesticide for generations. It is also used medicinally.
