Agriculture Reference
In-Depth Information
Changes in the behavior of almond trees had made them more
hospitable to the navel orange worm. Growers stimulated almond pro-
duction, and an unintended result was increased numbers of mummies.
Once a crawler (larva, commonly referred to as a “worm”) found
shelter in a mummy, it was home free, with old nutmeat for food and
near-complete protection from pesticides. The first generation of adult
females in the early spring would seek out mummies, attracted by
almond oil, and lay eggs nearby. This guaranteed that high numbers of
NOW would hatch in May, which in turn would reproduce and flood
orchards with their third generation, assuring high nut damage during
the vulnerable hullsplit stage. Subsequent research would reveal that the
peach twig borer and the NOW work as a tag team: peach twig borer
larvae chew through newly forming green hulls and shells, and the sub-
sequent generations of NOW can then access the nutmeat. Thus, the
peach twig borer creates a “food bridge” allowing NOW populations to
build up in the spring before hullsplit, and multiply rapidly once all nuts
become vulnerable.
Okamura, Post, and Hanke explained the life cycle of this pest to the
growers. Organophosphates could be effective, but only if they were
sprayed precisely when crawlers were seeking out the nut. Spraying at
the wrong time would make matters worse by killing off any generalist
predators and causing an explosion of mites. But they emphasized that
orchard sanitation in early was the most important technique: shaking
the trees to knock off mummies, and flail mowing them on the orchard
floor. Mummy removal must leave no more than one nut per tree.
Sanitizing one's own orchard is effective, but the effectiveness is
increased if it is done on an area-wide basis since NOW adults can fly up
to half a kilometer.
Bob Hanke did not think the growers would be willing to sanitize, but
they were. Decker described a palpable crisis among growers that
provoked interest in social learning beyond the norm. The leadership of
certain growers was very important to the success of this initiative. They
identified the problem, self-organized, invested their own resources, and
recruited specialists to address it. Individualism is the norm among
growers, but the NOW crisis forced this group to develop new social
relations. When Okamura asked the growers who sponsored him if they
would like to share the information with others, one of them, well
