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Central and Eastern counties in Arizona (Maricopa, Pinal, Pima, Graham, Cochise and Greenlee) have been authorized to participate in season long release of sterile Pink Bollworm moths in conjunction with entrance into a regional Eradication Program.

The San Joaquin Valley of California has, despite annual introductions of pink bollworm from the southern desert cotton growing areas, prevented population establishment for 38 years through the release of sterile pink bollworm moths on up to one million acres of cotton.  This is true for a variety of reasons namely:

1.       Competitive effectiveness:
Studies by Miller et. al. compared and verified that both male and female sterile pink bollworm moths are comparable to native moths in mating responses (Miller et al. 1994).

2.       Distribution:
Studies by Tabashnik et. al. reported that 66-94% of both native and sterile male pink bollworm moths moved up to 400 meters from non-Bt to Bt cotton (Tabashnik 1999).  This study suggests that sterile releases in an eradication program targeted within 400 meters (1/4 mile) of Bt cotton would provide pink bollworm population (males and females) within the boundary for effective interaction with native moths (either Bt susceptible or resistant).  Further data supplied by Keaveny, Program Data Analyst, with the California Department of Food and Agriculture, from the San Joaquin pink bollworm program verifies that targeted sterile moths released on one mile corridors move effectively at least one mile offsite for potential encounters with natives.  In fact, the Keaveny study documents sterile recapture (at reduced levels) at 2-3 mile increments beyond the sterile release corridors further validating the range of SIT releases.  The magnitude of trap recapture is also an additional testament to the sterile males’ potential to respond to pheromone from both traps and calling females.


The protocol for sterile release is as follows:

1.       Non-Bt Cotton:  Sterile moth releases are made three times per week directly over non-Bt fields at a rate equivalent to 100 moths per acre per day or higher.

2.       Bt Cotton:  SIT releases are made 2-3  times per week along one mile corridors over Bt fields at a rate equivalent to 20 moths per acre per day or higher.  This release rate represents a minimum of two times the USDA/APHIS release rate for Bollgard and Bollgard II referenced in Arizona’s 24 ( c ) label.  Corridors are offset by one half mile on alternate release days to ensure that sterile moth populations are maintained within one quarter mile of Bt fields at all times throughout the season.

3.       All SIT releases are monitored through GPS assisted guidance systems which produce flight recordings which are downloaded, printed and reviewed daily.  These include flight paths and color coded designations of all release operations.

4.       Arizona:  Allocation of sterile moths is 70 million moths per week for an overall average of 10 million moths per day.  Releases are made seven days a week and cover the period of May 1st through October 15, 2006.

5.       Pheromone traps on all Bt and non-Bt fields are serviced weekly and counts of native vs. sterile moths are recorded by trained ID personnel at each field office.  Because steriles are reared on a diet containing red dye, either visual or simple chemical assays separate steriles from natives. 

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