Split-Application of Bacillus thuringiensis israelensis to Control Asian Tiger Mosquito, Aedes albopictus (Skuse) (Diptera:Culicidae) without Reducing Lettuce Head Weight in Non-Circulating Hydroponics

Scientific note.Vectobac G (Bacillus thuringiensis israelensis) application at 1.08 and 0.54g/ m2 to subirrigated pot and suspended forestry tube methods of non-circulating hydroponics in an unreplicated experiment greatly reduced numbers of Asian tiger mos- quito, Aedes albopictus (Skuse) (Diptera: Culicidae), larvae and pupae compared to non-treated controls. Both Vectobac G rates, however, reduced lettuce head weight and root growth compared to the control. When the 0.54/m2 rate was applied as a split-application (0.27g/m2 applied 2 weeks apart), A. albopictus larvae and pupae were still controlled throughout the lettuce cropping cycle and lettuce head weight was not significantly affected. Therefore, the split-application of Vectobac G may be an effective strategy to control mosquitos breeding in commercialized non-circulating hydroponic lettuce operations in Hawaii

Use of Bacillus thuringiensis israelensis and Methoprene to Control Asian Tiger Mosquito, Aedes albopictus (Skuse) (Diptera: Culicidae), in Non-circulating Hydroponics Tanks

Bacillus thuringiensis israelensis, (Bti) and methoprene (isopropyl (2E-4E)-11-trimethyl-2,4-dodecadienoate) were tested for control of the Asian tiger mosquito, Aedes albopictus (Skuse) in non-circulating hydroponics tanks of lettuce. The results showed that Bti and methoprene formulations reduced mosquito larvae and pupae population for the duration of the lettuce crop (4 to 5 wk) compared to the non-treated control. Bti and methoprene treatments, however, caused reduced lettuce head weight and root growth. Leaf lettuce cultivars ‘Red Sails’ and ‘Green Ice’ were more tolerant to Bti treatment compared to ‘Manoa’. Lowering the Bti (VectoBac G) application rate from 1.04 to 0.54g/m2 increased head weight and root growth for ‘Manoa‘ lettuce. The tank treatments presented in this study were not replicated due to the use of large, commercial-scale tanks and limited greenhouse space

Pyronyl Crop Spray Effective in Controlling Larvae of the Asian Tiger Mosquito (Aedes albopictus [Skuse] [Diptera: Culicidae]) in Non-Circulating Hydroponic Nutrient Solution

One to two ppm of Pyronyl Crop Spray (Pyronyl) effectively controlled larvae of the Asian tiger mosquito Aedes albopictus (Skuse). The mean LT99 was 35.8 hrs for 1.0 ppm and 2.3 hrs for 2.0 ppm Pyronyl. Pyronyl concentrations of 0, 0.062, 0.125 and 0.25 ppm resulted in similar time to the LT99 (greater than 200 hrs). Pyronyl mixed in the nutrient solution at 1.25, 2.5 and 5.0 ppm did not reduce the mean head weight of lettuce grown in the nutrient solution for 5 weeks. Pyronyl at these concentrations did not affect root weight at 1.25 and 2.5 ppm, but a slight reduction in root weight was observed at 5.0 ppm. Based on these results, Pyronyl is an effective compound for commercial non-circulating hydroponic lettuce growers to use against A. albopictus. Growers typically add approximately 4.0 L of nutrient solution per plant, utilizing this approximation, 1.0 ml of Pyronyl solution per 125 plants would provide A. albopicuts control

Phototropism: Mechanism and Outcomes

Plants have evolved a wide variety of responses that allow them to adapt to the variable environmental conditions in which they find themselves growing. One such response is the phototropic response - the bending of a plant organ toward (stems and leaves) or away from (roots) a directional blue light source. Phototropism is one of several photoresponses of plants that afford mechanisms to alter their growth and development to changes in light intensity, quality and direction. Over recent decades much has been learned about the genetic, molecular and cell biological components involved in sensing and responding to phototropic stimuli. Many of these advances have been made through the utilization of Arabidopsis as a model for phototropic studies. Here we discuss such advances, as well as studies in other plant species where appropriate to the discussion of work in Arabidopsis