Agriculture Reference
In-Depth Information
clude fruit-tree bark beetle, lesser shothole borer, European ambrosia beetle,
and Asian ambrosia beetle. These pests were introduced from Europe and
Asia and are serious pests of forest, fruit, nursery, and landscape trees. The
adults are small, dark brown to black beetles with hard bodies. They bore in-
to trunks and stems, creating multiple-chambered tunnels or galleries in the
inner bark and outer sapwood.
The adults lay eggs in the galleries, and both adults and young inhabit
the tunnels, feeding on ambrosia fungus that is cultured and tended by the
adults. The larvae typically pupate in the tunnels and emerge as adults by
boring a hole out through the bark. The many entry and exit holes pro-
duce the characteristic shothole effect. The tunnels damage the phloem and
weaken the trees, and the ambrosia fungus can block the vessels that carry
water and food. Fusarium and other pathogens can also be introduced into
trees. There are no effective chemical controls for organic fruit growers. The
best strategy appears to be keeping your trees healthy because these pests
sometimes prefer to target weakened trees.
Pacific Flatheaded Borer
The larvae of this reddish-brown or coppery beetle bore beneath the bark
and can girdle the trees. Apples, cherries, plums, and other stone and pome
fruits are hosts of this borer. Young trees are at greatest risk of girdling, and
the adults target sunburned or otherwise damaged areas of the trunks. There
are no recommended organic chemical controls. Wrapping the tree trunks
and shading them with boards may help prevent sunburn and make the trees
less attractive to adults. Applying Surround should also help reduce sunburn.
Peachtree Borer and Lesser Peachtree Borer
Peachtree borer and lesser peachtree borer are common pests across North
America, particularly east of the Rocky Mountains. The peachtree borer
adult is a steel blue moth, and the females have a distinctive orange band
around their abdomens. Besides peaches, these borers attack cherries, plums,
