Butte County Year One Report


The orchard is about 49 acres with a grower standard block of 27 acres,
reduced risk block of 22 acres further divided into a 12 acre soft
treatment and a 10 acre OP dormant treatment. Five of these ten acres
received an OP hullsplit spray.

NOW traps were placed in early May and three biofix dates occurred, but
overall there were very few eggs detected throughout the orchard. These low
populations can be attributed to winter sanitation. Mummy counts taken in
February 1999, show that out of 20 randomly chosen trees in each block,
totaling 80 trees, there was less than 1 mummy nut per tree. Winter
sanitation is the most effective means of controlling NOW.

Mites
Dormant samples showed that over 50% of the spurs collected in each block
had mite eggs present. Mite monitoring began on 6-23-99 and continued
weekly until the end of August. At each sampling, (every other week) five
trees per block were chosen randomly and fifteen leaves from each of the
five were collected and inspected for red mites, two-spotted mites,
predatory mites, and beneficial insects. The only increase in mites and
their predators occurred on 9-16-99. Since this population occurred late in
the season, and defoliation was minimal, these mites will not be
detrimental to tree performance next year.

The PMA program in this orchard has been implemented well. As of harvest,
there is virtually no damage in any of the four treatment areas. However,
in order to determine if there are differences in treatments, data must be
collected for a number of seasons. We plan to continue this project in the
same manner next year with little or no changes in procedure. By continuing
the data collection and monitoring over the course of many seasons,
additional insight to environmentally friendly means of pest control can be
determined.