Fuller Rose Beetle Response to Insecticides, 2018

Fuller rose beetle adults feed on leaves and damage the new flush of top-worked trees. The beetle itself does not generally cause economic damage to citrus but the presence of viable eggs on fruit exported to other countries can be a quarantine concern. A field experiment was conducted in a 48-yr-old ‘Atwood’ navel orange block at the Lindcove Research and Extension Center, Exeter, California, to test the efficacy of insecticides to kill adults and minimize egg laying. Insecticides were applied in an RCB design to 10 trees per treatment with blocking based on tree rows using a 100-gallon high-pressure D30 diaphragm pump sprayer with mechanical agitation at 200 psi in 500 gpa. Foliar treatments were first applied on 16 and 17 Aug 2018 and treatments were repeated on 16 and 17 Oct. All the fruit from each tree was harvested during 3 to 31 Jan 2019. The number of fruit per tree was recorded. Each fruit was examined for live Fuller rose beetle eggs by lifting the calyx with a small scoop and the presence of eggs was recorded. Data were analyzed using one-way ANOVA after testing for an NS block effect. Means for the percentage of fruit with live eggs were transformed with arcsine square root(x) and the means were separated according to Fischer’s protected least significant difference test (P = 0.05).

All treatments significantly reduced the percentage of fruits with live Fuller rose beetle eggs compared with the untreated trees (Table 1). There were no significant differences between the insecticide treatments. None of the treatments completely eliminated Fuller rose beetle eggs.¹

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