Improved Pest Control From Macho Hormone Treated Male Fruit Flies

Mexican Fruit Fly Anastrepha ludens © Jefferey W Lotz (CC-BY-3.0-US license, via Wikimedia Commons)

The Mexican Fruit Fly Anastrepha ludens is the most important native fruit fly pest of citrus in America and also infests other economically important crops such as peaches, peppers and mangoes. In cooperation with the U.S. Department of Agriculture, Mexico has developed a Sterile Insect Technique (SIT) method which involves exposing huge quantities of male fruit flies to irradiation before releasing them en masse  to mate with wild female flies. The male flies are exposed to enough radiation to sterilise them, so that mating with wild females results in the production of non-viable eggs. Over time repeated releases of large quantities of sterilised male flies causes the target pest population to collapse. The use of the SIT applied as part of an area-wide integrated pest management approach provides an environmentally safe and species-specific method to suppress, and in some cases eradicate insects of agricultural, veterinary and medical importance worldwide. The success of the SIT in effectively controlling target pest insect populations requires males to be able to successfully compete against wild unsterilized males to mate with females. Recent developments to improve SIT program effectiveness have been discovered by scientists from the Agricultural Research Service who found that the use of methoprene, an analogue of an insect hormone, and additional protein hydrolysate in the fruit fly diet helped to make sterilised males more “macho” by increasing their competitiveness in the wild, therefore making them more attractive as a mate to females.

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RIDL baffles Pink Bollworms

Pink bollworm larvae, photo by Peggy Greb, USDA Agricultural
Research Service, Bugwood.org

It was love at first sight for many pink bollworms this year, but as their eyes met across the cotton field all was not as it seemed…

Oxitec (a company based not far from the Plantwise Knowledge Bank team), have managed to genetically engineer a strain of pink bollworm (Pectinophora gossypiella) which greatly advances the already used sterile insect technique (SIT). The new strain (affectionately known as Pink Bollworm OX3402) has been genetically engineered to include bisex RIDL technology, which means that they have a RIDL gene that effectively makes them sterile (offspring cannot survive without additional dietary supplements). OX3402 also has Oxitec’s heritable fluorescent marker technology (DsRed), which allows populations of released strains to be monitored more accurately.

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