Agriculture Reference
In-Depth Information
1962, only a few years after their discovery, scientists started using
codling moth pheromones to investigate sex in the field. George Post,
who was then a Farm Advisor, recalls his first use of a monitoring trap
with live female moths in a screened cage, which helped him to follow
codling moth adult abundance over time. He discovered that the indus-
try-standard spray after pear petal fall was entirely pointless because no
young codling moth larvae were present in the orchard at that time. This
led him to believe that to truly serve growers' needs, technology requires
the support of expert knowledge. He quit his position with Cooperative
Extension and became the first independent consultant in the
Sacramento Valley, before the state even began issuing PCA licenses.
When DDT was introduced, the University of California's recommen-
dations for spraying were based on the phenology of crops, not insect
pests, and growers would apply them on a calendar basis, generally every
other month during the growing season. This would kill all the insects in
the orchard, and leave a residue on the fruit that would kill codling moth
larvae after they emerge from eggs but before they are able to enter the
fruit. The codling moth is thought to have evolved with apples in the
mountains of what is now Kazakhstan, and migrated with that fruit
to what is now Europe, where it found the pear and walnut also to its
liking.
The codling moth co-evolved with the apple fruit, but readily damages
pears and walnuts. The moths over-winter as full-grown larvae in tree
bark, old branches, or in the soil at the base of the tree. Once tempera-
tures reach 55ºF, they pupate, emerge, and mate. A few weeks later,
females lay up to 70 pinhead-size eggs in a scattershot on fruit, leaves, or
calyx (clusters of fruit stems). Larvae emerge from eggs, and within 24
hours find and burrow into the developing fruit. From that point on, this
generation is home free—pesticides cannot reach inside the fruit. When
they emerge as adults, they begin again the cycle of mating, laying eggs,
and burrowing into fruit. The development of both fruit crop and insect
pest are regulated by environmental heat, and most seasons a grower can
apply a pesticide based on the calendar date, but not consistently enough
to gamble one's crop on it.
The same US Department of Agriculture IPM initiative that paid for
the Ballico/Formosa Project in almonds funded Extension Specialist
Clancy Davis at UC Berkeley from 1973 to 1976 to develop an IPM
