DOI: 10.25338/b8v06h
title: Evaluating control methods for red imported fire ant (Solenopsis invicta) and their effects on hibiscus mealybug (Nipaecoccus viridis) and its natural enemies in citrus

description: The red imported fire ant (Solenopsis invicta) may disrupt biological
 control of hibiscus mealybug (Nipaecoccus viridis) in Florida citrus.
 Controlling S. invicta may therefore be necessary for effective management
 of hibiscus mealybug. We evaluated four different methods to control S.
 invicta (ground applications of insecticide, two different insecticidal
 ant baits, and spot treating ant colonies with hot water) to determine how
 these different treatments affected ants tending to hibiscus mealybug
 colonies, natural enemy abundance within hibiscus mealybug colonies, and
 hibiscus mealybug colony abundance. While all treatments reduced the
 number of S. invicta colonies in treated areas compared to an untreated
 control, only ground applications of insecticide and the two ant baits
 significantly reduced the abundance of S. invicta found tending hibiscus
 mealybug colonies. Additionally, significantly more Brachymyrmex obscurior
 ants were found tending mealybug colonies in plots treated with either of
 the two ant baits. There was no significant effect of treatment on the
 abundance of natural enemies in hibiscus mealybug colonies, but
 significantly fewer natural enemies were found in mealybug colonies tended
 by S. invicta, and significantly more natural enemies were found in
 mealybug colonies tended by B. obscurior. Ground applications of
 insecticide, the abamectin ant bait Clinch and hot water treatments all
 reduced the overall number of hibiscus mealybug colonies compared to
 control areas, while the S-methoprene ant bait Extinguish did not. Our
 results suggest that reducing the number of S. invicta tending hibiscus
 mealybug colonies can lead to higher natural enemy abundance and lower
 hibiscus mealybug abundance. However, methods used to control S. invicta
 may have different impacts on ant species like B. obscurior, leading to
 different outcomes with natural enemies.
description: Data were collected in a 26-acre commercial Valencia orange grove
 in Lake Wales Florida USA (27°50'34.55"N,
 81°34'29.99"W). Plots were laid out in a Randomized Complete
 Block Design, with five treatments and six blocks. Five treatments were
 assessed: 1) An untreated control; 2) Ground applications of insecticide
 consisting of chlorpyrifos and later, bifenthrin at a rate of 1 qt/acre
 for chlorpyrifos, and ~22.5 oz/acre for Bifenthrin; 3) An abamectin ant
 bait (Clinch) at a rate of 1 lb/acre; 4) An S-methoprene ant bait
 (Extinguish) at a rate of 1 lb/acre; and 5). Hot water applications to
 individual ant mounds.<br><br>Sampling took place between
 March 2021 and March 2022. Natural enemies and foraging ants were sampled
 by collecting mealybug clusters from the grove. S. invicta colonies were
 sampled by counting individaul colonies in the grove. Mealybugs were
 sampled by visually counting colonies. <br><br>Data were
 recorded in excel with minimal additional processing. More specific
 information is included in individual excel files.
description: Data were recorded in Excel.