By reviewing this data, does that mean
everyone across the state needs to
sanitize to less than 0.7 mummy nuts per
tree
?
The short answer is “it depends.”
Insect pressure will vary by location due
to more degree days and lower rainfall
that is generally characteristic of the
southern San Joaquin Valley and some
micro-climates in the Sacramento Valley.
Regardless of location, all of the research
indicates that the fewer mummies within
the orchard (both tree and ground), the
less NOW damage to expect at harvest.
Therefore, higher standards of tree and
ground sanitation are recommended
for orchards in high pressure, higher
heat unit/degree day areas
.
Growers
in cooler, low pressure areas should still
reduce average mummy nut counts to 2
or less per tree and destroy any mummies
that are on the ground.
Pruning: Should I Throw Away
the Shears?
Pruning of mature and young trees
often occurs during the winter months.
Research has shown that reduced
pruning on younger trees can lead
to larger, earlier yields. This is mostly
due to increase canopy that is able
to produce crop. Nevertheless, some
structuring of first and second leaf trees
may be needed to address tight branch
angles and close proximity of scaffolds,
which leads to included wood and
weak branches. These branches will split
when the crop load begins to increase,
typically around year four or five. Prune
only when rain is not in the forecast to
avoid wound infections by pathogenic
fungi that disperse spores during rain
events. Wounds can be susceptible up
to two weeks after pruning, with larger
wounds taking the longest to heal. Even with this healing time, pruning
paints are not recommended as they can slow the healing process.
Pruning as late as leaf out will have no impact on tree growth.
Mature tree pruning may also be needed. Many are aware of the
multiple research trials that have shown no yield benefit from pruning
mature trees. There are, however, other reasons to prune mature trees,
including: easier access, worker safety, increasing the amount of light to
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