The hibiscus mealybug, Nipaecoccus viridis, is an invasive species that has emerged as a pest of economic importance for horticultural crops and ornamental plants in Florida. On citrus, feeding damage results in fruit distortion and reduces fresh fruit marketability. Its cryptic behavior in combination with its waxy coating limits the efficacy of insecticides. This species is particularly challenging to manage in semi-enclosed systems such as Citrus Under Protective Screen (CUPS). In this presentation, we will highlight the main findings of two research programs that will help in implementing IPM programs for this mealybug in Florida citrus.
An Electropenetrography (EPG) study testing different wiring materials and monitor settings (i.e. change in substrate voltage and input resistance) helped us to better characterize the feeding behavior of 2nd and 3rd instar hibiscus mealybugs. Results will serve as a baseline for future studies evaluating the interaction of systemic insecticides with the feeding behavior of the mealybugs.
A field study comparing the residues of four insecticide applications in CUPS and open orchard revealed different degradation rates in the two systems depending on the active ingredient tested. In CUPS, some insecticides degrade slower due to the presence of a screen mesh that filters UV lights leading to higher mealybug mortality. These results will be used to tailor IPM programs in CUPS but could also be transferred to other controlled environment production systems such as greenhouses or high tunnels.
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