The Stanislaus County PMA site is a research trial as well as a
demonstration orchard. The trial is being conducted in a uniform
120-acre orchard of Nonpareil and Carmel, west of Modesto. Three
insect pest management program treatments are fully replicated
three times within the 120-acre orchard. Each plot is
approximately 13.5 acres. The pesticide
treatments include:
* Grower Standard Practice - a dormant application of a pyrethroid, copper and oil, Lorsban in May, and Omite in July and August to control mites.
*The Intermediate Program with reduced risk pesticides included a dormant spray of Success, copper and oil, a May spray of Success, oil and Agri-Mek (1 replication only).
*The Soft program used dormant oil alone, two bloom
applications of Bt , two May applications of
Bt and Agri-Mek and oil (1 replication only).
Mummies were removed and destroyed in all treatments. Mummy
counts recorded in February averaged 0.4 mummies per tree.
There were no significant differences between treatments.
Resident vegetation was managed with periodic mowing. The
fertilization and fungicide treatments did not differ between
programs. Mites were monitored with the presence/absence method,
but next year the recommendation is to do fewer leaves per tree
and do more trees.
During the first half of the season there tended to be fewer
peach twig borer, San Jose Scale, and scale parasites in the
dormant pyrethroid treatment. There did not appear to be
differences between the intermediate and soft programs. All NOW
eggs on traps were laid within the first two weeks of the trial.
Cumulative trap catches through 6-15-99 for PTB and San
Jose Scale. Scale males (pheromone traps), Prospaltella, Aphytis
and NOW are listed below for these treatments.
Cumulative number of Arthopods through June 15 1999
PTB SJScale Prospaltella Aphytis NOW
Standard 1876 27 3287 15 30
Intermediate 3066 54 6207 16 0
Soft 2117 59 7150 30 0
By the end of the season, there was no apparent difference in
peach twig borer catches between the growers' standard treatment
and the two softer programs. However, fewer SJ scale and scale
parasites continued to be captured through the season, Cumulative
trap catches through 9-30 for PTB and SJ scale males (pheromone
traps), Prospaltella, Aphytis and NOW are listed below for the
treatments.
Cumulative number of Arthopods through September 30 1999
PTB SJScale Prospaltella Aphytis NOW
Standard 7641 229 3976 166 30
Intermediate 8588 480 7854 188 0
Soft 7652 558 9728 188 0
At harvest, 200 Nonpareil nuts per rep (600 per treatment) were
examined for damage from peach twig borer, NOW and ants. Damage
was very low in all treatments.
Harvest Crackout Results
%NOW %PTB %Ant Shrivled %NOW between hull & shell
%PTB between shell & shell
Standard 0.3 0 0.2 3.2 0.3 0
Intermediate 0.5 0 0 2.3 1.2 0.2
Soft 0 0 0.2 2.2 0.3 0