Potential for Using Acetic Acid Plus Pear Ester Combination Lures to Monitor Codling Moth in an SIT Program.

Gary Judd

doi:10.3390/insects7040068

Abstract

Studies were conducted in commercial apple orchards in British Columbia, Canada, to determine whether lures combining ethyl-(E,Z)-2,4-decadienoate, pear ester (PE), with either acetic acid (AA) or sex pheromone, (E,E)-8,10-dodecadien-1-ol (codlemone), might improve monitoring of codling moth, Cydia pomonella (L.), in an area-wide programme integrating sterile insect technology (SIT) and mating disruption (MD). Catches of sterile and wild codling moths were compared in apple orchards receiving weekly delivery of sterile moths (1:1 sex ratio) using white delta traps baited with either AA or PE alone, and in combination. Sterile and wild codling moths responded similarly to these kairomone lures. For each moth sex and type (sterile and wild), AA-PE lures were significantly more attractive than AA or PE alone. Bisexual catches with AA-PE lures were compared with those of commercial bisexual lures containing 3 mg of codlemone plus 3 mg of PE (Pherocon CM-DA Combo lure, Trécé Inc., Adair, OK, USA), and to catches of males with standard codlemone-loaded septa used in SIT (1 mg) and MD (10 mg) programmes, respectively. CM-DA lures caught the greatest number of sterile and wild male moths in orchards managed with SIT alone, or combined with MD, whereas AA-PE lures caught 2–3× more females than CM-DA lures under both management systems. Sterile to wild (S:W) ratios for male versus female moths in catches with AA-PE lures were equivalent, whereas in the same orchards, male S:W ratios were significantly greater than female S:W ratios when measured with CM-DA lures. Male S:W ratios measured with CM-DA lures were similar to those with codlemone lures. CM-DA and codlemone lures appear to overestimate S:W ratios as measured by AA-PE lures, probably by attracting relatively more sterile males from long range. Using AA-PE lures to monitor codling moths in an SIT programme removes fewer functional sterile males and reduces the need for trap maintenance compared with using codlemone lures. AA-PE lures allow detection of wild female moths that may measure damage potential more accurately than detection of wild males. The short-range activity of AA-PE lures compared with that of codlemone-based lures appears to improve the ability to measure S:W ratios and the impact of SIT on population control near the site where wild moths are trapped.

Highlights

During the 1990s, several area-wide programmes to manage codling moth, Cydia pomonella (L.)(Lepidoptera: Tortricidae), were implemented in commercial apple production areas of western NorthAmerica [1]
The relative catches of sterile and wild codling moths with different kairomone lures appear similar in orchards managed by sterile insect technology (SIT) (Table 1)
This seasonal catch is about 2.7× more than the number of sterile males caught with acetic acid (AA)-pear ester (PE) lures (Table 1)

Summary

Introduction

During the 1990s, several area-wide programmes to manage codling moth, Cydia pomonella (L.)(Lepidoptera: Tortricidae), were implemented in commercial apple production areas of western NorthAmerica [1]. Whereas pheromone-based mating disruption (MD) was the basis of these programmes in the United States [2], in Canada, the area-wide pest management paradigm was founded on previously developed sterile insect technology (SIT). The Canadian SIR Program revised its objective, and area-wide suppression to keep damage below economically acceptable levels became its new target [4,5]. This Canadian SIR Program currently uses an integrated approach to achieve its objective by using insecticides and/or MD in high-risk orchards as supplements to the area-wide SIT programme [6,7]. SIT programmes have an additional need to estimate the ratio of sterile (S) and wild (W) insects in mating populations

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Discussion

Conclusion