Efficacy of an Experimental Pesticide Against Green Peach Aphids, 2016

We measured the efficacy against green peach aphid, Myzus persicae, of six concentrations of an experimental material, ADA 43161 and two labeled insecticides, Alias 4F and Hexacide compared with an untreated check (listed in Table 1). Approximately 3 wk prior to initiation of experiment, radish seeds were planted in two 50-cell trays (cell width 3.8 cm). The radish seedlings were grown indoors under lights at 22°C and 16:8 h light:dark cycle, and bottom watered with a solution of Scott’s Complete Liquid Plant Food at a rate of 1 tbsp/gal water. On 18 Jan, when plants had two true leaves, trays were cut apart to separate the plants, and five mature green peach aphids were placed on the top-most leaf of the 45 largest plants. Immediately after aphids were placed on plants, treatments were applied to plants via a Potter Spray Tower (Burkard Scientific, Uxbridge, UK) loaded with 5 ml of solution. Five plants were sprayed per treatment, and untreated plants received no spray of any kind. After treatment, each plant was placed in a 16-oz deli cup with a another plant tray cell glued into the center to help hold the plant pot upright. These deli cups were partially filled with the same liquid fertilizer solution described above to provide individual water sources for each plant without the risk of cross-contamination between treatments. Plants were placed in a large cage covered with insect-excluding fabric on a greenhouse bench. The greenhouse temperature did not fall below 26°C, and supplimental lighting was provided above the cage to ensure a 16:8 h light:dark cycle. The number of aphids and nymphs on each plant was counted 1 DAT, and the total number of aphids on each plant was counted 5 and 7 DAT. Data were analyzed via Proc Glimmix in SAS v.9.4 with treatment as a fixed effect and replicate as a random effect. A log-normal distribution was used for the model as it was a better fit for the data than a normal distribution. If the assumption for homogeneity of variance was not met, a Satterthwaite correction was used to adjust the degrees of freedom.

Alias 4F killed all aphids on the plants treated with it by 1 DAT, and no aphids successfully immigrated to these plants during the course of the experiment. Compared with the untreated check, significantly fewer adult aphids per plant survived the Hexacide treatments at 1 DAT, and no nymphs were found on Hexacide-treated plants 1 DAT. This treatment had significantly fewer aphids per plant than the untreated check for the remainder of the experiment. At 1 DAT, only the 0.05% concentration of ADA 43161 showed slight, but significant, adult mortality compared with the untreated control. Also at 1 DAT, the 0.05% and 0.06% ADA treatments had significantly fewer nymphs per plant than the untreated check, but significantly more than the Hexacide treatment. The 0.06% ADA 43161 treatment had significantly fewer aphids per plant than the untreated check, but significantly more than the Alias and Hexicide treatments at 5 and 7 DAT (Table 1).

This research was supported by industry gifts of product and funding.