Each of the three regional demonstration orchards have completed
their
first growing season. The following is a brief description of the
Kern County site and
some of the highlights from each system.
Kern County
The Kern orchard is a fifth year orchard with two 40 acre blocks
of
Nonpareil, Fritz and Sonora and two 40 acre blocks of Butte,
Mission and
Padre. One of each pair was treated under a conventional pest
management
strategy and the others utilized a reduced risk program.
The demonstration started in November 1998 with the planting of a
barley
cover crop. The barley was selected because of the saline-alkali
soil and
the poor drainage condition of the soil. At the same time, the
BIOS
insectary mix was planted on every 11th middle. The barley
germinated well
and created a solid cover. It did improve the drainage of the
soil and
provided a cool environment. The insectary mix was not as
successful and
many of the species including the clovers did not germinate at
all.
A dormant OP spray was applied to the conventional blocks with no
treatment
applied to the reduced risk blocks. Monitoring results show that
the
dormant spray didn't completely eliminate the PTB in the orchard.
No Bt
sprays were used in either conventional or reduced risk blocks.
Mites
Mites are the most difficult and most expensive pest to manage in
Southern
San Joaquin Valley almond orchards. The PMA blocks were all well
watered.
Predator mites were released in the reduced risk blocks and
well-timed
Omite sprays were used in the conventional blocks. Predatory
mites were not
released in the reduced risk blocks until the populations of
webspinning
mites increased to a food supply level. At this time (7-19-99)
2,500
predatory mites per acre were released. This release didn't
appear to be
controlling the mites and so on 8-11-99, a second release of the
same
amount was made. Following the second release the presence of
webspinning
mites began to decrease. Mites remained under control in both
systems.
One of the biggest problems for almond growers in Kern County is
ants. They
can cause more damage in almond orchards than NOW and/or PTB. The
primary
factors which influence damage include the population of ants in
the
orchard and the length of time the nuts are left on the ground to
dry. Ant
populations peaked in both the conventional and reduced risk
blocks in late
June. The new bait product Clinch was applied in all orchard
blocks, but
due to late registration and the time it takes the material to be
effective, it was difficult to determine its efficacy.