|
|
Walnut
> Year-Round IPM Program > Harvest > Identifying
Pests in Harvest Samples
Walnut
Identifying Seasonal
Pests in Harvest Samples
Observe nut damage at harvest to identify pests that escaped
your management program.
Look for the presence or evidence of navel orangeworm, walnut husk fly, codling
moth, and ants. Knowledge of the current year’s problems will help plan
for next year.
Look through walnuts collected for the harvest sample. Use the
photos below to identify pests (and sunburn) that cause damage.
Names link to more information on identification and management.
Click on photos to enlarge
Photos
of nut damage |
Kernel |
Frass |
Webbing |
Boring |
Feeding behavior |
Other |
Navel orangeworm
|
Deep chewing into kernel. |
White, often quite a lot. |
Yes, often quite a lot. |
Yes, into kernel. |
Larvae feed in groups.
Many per kernel. |
Shells of heavily infested nuts
appear oily. |
Codling moth
|
Deep chewing into kernel. |
Frass at point of entry into
the husk. |
Very little. |
Yes, into husk and kernel. |
Single larva feeds per kernel. |
NA |
Ants
|
Tunnels chewed into the kernel. |
No |
No |
No |
Ants feed in groups. |
|
Walnut husk fly
|
Early season infestations may
cause shriveled/
darkened kernel.
Late season infestations do little kernel damage. |
No |
No |
Yes, into husk. |
Larvae feed in groups.
Many larvae per husk. |
Husks are blackened and shell
is stained black.
Husks cannot be removed cleanly from shell. |
Sunburn
|
One side of the nutmeat darkened
and shriveled. |
NA |
NA |
NA |
NA |
One side of husk darkened and
shriveled.
Husks can be removed cleanly from shell. |
|
