Note: Control mortality on the 7-day assessment (24.7 percent) was higher than the 0-day and 14-day assessments possibly due to very high temperatures. Seven days after the application, the insecticides that still had above 60% mortality were: Closer, Imidan, Actara, Danitol, Carbaryl, Brigade, and Vydate. Of the insecticides tested on peach in the table above, 14 of the 16 chemicals had excellent knockdown activity. ![]() “i”) represent lower mortality levels and means followed by the same letter were not significantly different. The letter “a” represents the compounds with the highest mortality level, while the subsequent letters (i.e. Insecticide results for control of spotted lanternfly nymphs on peach Product nameĭifferent letters following each percent mortality mean within a column indicate a significant difference at a 95% confidence limit. Compounds that do not appear in the 7-day and 14-day columns were not evaluated because of low mortality in the preceding assessment. The average percent mortality of each of these compounds compared to an untreated control are presented in the table below. Rain-fastness was not evaluated in this study, but heavy rains did occur prior to the 14-day assessment and some products did not last as long as expected, which could be explained by the rain. All treatments except Brigade failed to give at least 50 percent mortality and the experiment was discontinued at that time. Those products that were still performing well were assessed again with new (mostly 4 th instar) nymphs 14 days after the spray application, assessing mortality 48 hours later. ![]() If products failed to give at least 50 percent control at this time they were considered to have failed and further evaluations were discontinued. Using the same sprayed peach trees (application was made only once), we placed new nymphs (mostly 3 rd instar nymphs) 7 days after the insecticide application and again assessed mortality after 48 hours of exposure. Some of these products are being evaluated for longer-term feeding trials, but they were removed from this study, so 17 products are shown in the table. Products that failed to give 50 percent mortality at this time and were discontinued from this study. Contact insecticides such as pyrethroids, carbamates and organophosphates kill quickly by contact, but others such as neonicotinoids may kill more slowly by interfering with the insect nervous system or feeding. Nymphs barely alive, but clearly intoxicated (moribund) were recorded as well, but for the purposes of this analysis were considered dead. Mortality was assessed after 48 hours of exposure and all SLF were removed from the tree at that time. Some products also have long re-entry periods that restrict activities in the vineyard for periods of several hours to several days, depending on the product used and the rate of application.įor this evaluation, we placed field collected 3 rd instar nymphs on peach trees in net cages after the spray had dried (about 30 minutes). Some products have long pre-harvest intervals that prevent late season spraying just before harvest, which is often when the adult SLF are most active. Peach and grape growers typically apply on a 10-14 day schedule, so the goal was not to determine mortality by spraying the nymphs directly on the tree. Previous work has shown SLF nymphs and adults to be very susceptible to direct sprays, but the goal of this trial was to assess how long the sprays would last (residual activity) and how often sprays would need to be re-applied to protect the crop. Please note that while we are currently carrying out insecticide efficacy trials for spotted lanternfly on grape, the data presented below is on peach. In this experiment, we sprayed peach trees (2-year-old in 5-gallon pots) using the maximum labeled rate of the insecticide for peach at a typical spray volume of 50 gallons/acre. We tested 20 different insecticides for their efficacy against SLF nymphs on peach trees. Results from 2018 insecticide trial on SLF nymphs For more information about the damage that SLF causes, see ” Spotted Lanternfly on Grapes and Tree Fruit .” In areas with heavy feeding, grape growers have reported yield loss, reduced berry quality, and vines not being able to survive the 2017-2018 winter. Most damage has been reported from SLF adults, which have been observed aggregating and feeding heavily on grapevines. SLF does not feed on the fruit, but instead feeds on the plant sap from the trunk and vines. Both nymphs and adults of this pest have been reported feeding on grapevines, and there is no current economic threshold for SLF damage. Evaluation of insecticides for managing this insect in the 2018 growing season are ongoing, and we present the most up-to-date data below. ![]() Spotted lanternfly (SLF) is an invasive and important pest for grapes in Southeastern PA.
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