Special Report 2006:

Local Movement of Sterile Pink Bollworm Moths In The San Joaquin Valley
of California

Dan Keaveny , Jim Hessler , Jim Rudig, California Department of Food and
Agriculture  and Robert Staten ,Consultant ,University of Arizona

Introduction:    Many attributes of the climate in the San Joaquin
Valley are extremely conducive to Pink Boll Worm (Pectinophora
gossypiella)  population development .  No sustainable population has
ever been found.  This has correctly been attributed to a continuous 36
year program relying almost exclusively on detection and sterile
release. The fundamental processes and procedures have remained
unchanged throughout this time. Sterile moths are released on all
sections (square mile) during the beginning of a current season where
native, non sterile moths were detected in the previous season.  As the
current crop is accurately mapped any section without a current cotton
crop is removed from a release zone.  As non sterile moths are detected
in a current season in non released sections a release zone is expanded
to include that new section. This results in a period during July and
August when releases are relatively stagnant or  constant. This offers
an ideal place and time to use programmatic data to asses dispersal away
from the targeted section of release. It is important to note that error
in aircraft is rare or nearly non existent . All aircraft flights are
guided ,monitored and recorded using a global positioning system (
Trimble 170 field computer ag. GPS Trimflight 3 System).  The flight
pattern is north to south using five “swaths” starting at the west
edge, ¼ mile, ½ mile, ¾ mile and the eastern edge of a release
section.  Releases are made on these lines three times a week.

Methods and Materials:  Adult Pink Bollworm populations are monitored
using a program wide standard  PBW delta trap and a standard 2 mg
concept lure. Traps are placed in the southern part of this zone at 1
trap per 60 acres and in the remainder on the area used in this study at
1 trap per 80 acres. The release area used in this study was in Kern
County. No other release section could be within 6 miles of the closest
release study section. Trap data was then sorted for all traps as 4
distinct capture zones. These are the area within the section of release
(release zone), all traps in an area from the zone boundary to an outer
boundary of 1 mi (zone 1), all traps from the 1 mile boundary to a 2
mile boundary (zone 2), and all traps from the 2 mile boundary to a 3
mile boundary (zone3).  All data was manipulated in Map Info.  The
number of acres in each band and the actual data including total moths
per week could be used as all trap locations and all field boundaries
are obtained with GPS units. 

 Results:   The field arrangement and spatial relationships of each data
zone is shown in the attached map (Attachment 1). Sections which
actually contain fields are marked on this map. All traps are then
placed in fields. This gives a frame of reference as to where the data
actually comes from. All trap date are based on numbers of sterile moths
per week. Attachment 2 provides a summary of total moth capture in each
zone over all times that the study is conducted.  The zone or band
covering the mile adjacent had almost as high a number of a total moth
capture as the targeted sections.  Moth activity is still readily
apparent over the next two bands even though it is reduced as expected. 
This study is conducted during the time when the pink bollworm moth is
the least mobile and is most prone to remain in favorable habitat. 
Attachments 3 gives more detailed data including total recapture over
seven weeks and the number of positive traps i.e. traps with one or more
sterile moths in each zone.  This table also provides basic acres in
each zone and total traps used in each zone.  All data is then expressed
in percentage points for comparative purposes.

Conclusions:   The most important and simple conclusion is that almost
as many moths reside in the mile zone around a release zone as within
it.  This is not surprising as release is at 500 feet to ensure moth
flight before their fall to the ground can be completed.

 

VOLUME 2

DOCUMENT 1

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