Carbohydrate-based mosquito control: A field test of the concept

We tested the concept of using a carbohydrate-based mosquito control method on saltmarsh mosquitoes. In laboratory trials, xanthan gum, a type of carb ohydrate gum thickener, killed both fourth-in;tar and pupae of Aedes sollic itans (Walker). The lethal time 50 was shorter for the pupae than the fourt h instars, 35.8 and 61.2 min, respectively, In a screen of commercially ava ilable carbohudrate gum thickeners slid starches we did not find anl compou nds that had properties, other than xanthan gum, useful for testing the con cept of carbohydrate-based mosquito control. Therefore, in the field study, we tested xanthan gum at the maximum rates used previously, 22 g/m(2). Thi s allowed us to test the concept of using such a control strategy in field conditions. Under these conditions, xanthan gum increased the Ae. sollicita ns mortality rate to 67% (+/-3.9% SE), a level not significantly different from the Abate treatment, 73% mortality (+/-7.7% SE). We also examined the effect of xanthan gum and a commercially available starch, National 5370, o n the biological oxygen demand (BOD) in the marsh environment. This allowed us to determine at what rate a practically applicable carbohydrate would h ave to be delivered to the marsh environment such that the BOD is not affec ted. Our initial findings suggest a practically applicable carbohydrate-bas ed mosquito central agent would have to be delivered at or below 2.2 g/m(2) .