Aleurothrixus Floccosus Research Articles

Chlorpyrifos and Diazinon as Barriers to Argentine Ant (Hymenoptera: Formicidae) Foraging on Citrus Trees1

Argentine ant, Iridomyrmex humilis (Mayr), was effectively excluded from foraging in citrus trees by removing foliage from tree canopy (skirt-pruning) within 60 cm of the ground and by applying 2% (AI) liquid chlorpyrifos 4 emulsifiable concentrate to the basal 15 cm of the trunk, or by placing a ring of 13 g (AI) diazinon 14 granular (G) on the ground adjacent to and around the trunk. These treatments were effective for 8 and 3 months, respectively. Applications of limonene to the basal trunk area of skirt-pruned trees, or uniform distribution of 32 g (AI) diazinon 14 G beneath the canopy of unpruned trees did not prevent ants from foraging in the trees. Data suggest that in the absence of ants, populations of honeydew-producing citrus mealybug, Planococcus citri (Risso), and woolly whitefly, Aleurothrixus floccosus(Maskell), and nonhoneydew-producing California red scale, Aonidiella aurantii (Maskell), were effectively reduced by their respective natural enemies. Populations of honeydew-producing species declined sooner than populations of California red scale.

Whitefly (Hemiptera: Aleyrodidae) Egg Pedicel Insertion into Host Plant Stomata

The egg pedicel of the following whitefly species was inserted into host plant stomata during oviposition: Orchamoplatus mammaeferus (Quaintance and Baker), Aleurothrixus floccosus (Maskell), Singhius hibisci (Kotinsky), Aleurodicus dispersus (Russell), Crenidorsum sp., Dialeurodes citrifolii (Morgan), D. kirkaldyi (Kotinsky), Aleurocanthus spiniferus (Quaintance), Odontaleyrodes rhododendri (Takahashi), Paraleyrodes naranjae (Dozier), P. perseae (Quaintance), and Aleyrodes shizuokensis Kuwana. The egg pedicel of Bemisia tabaci (Gennadius) and Trialeurodes vaporariorum (Westwood) were inserted nonstomatally, directly into host plant tissues.

Temperature Tolerance of Three Whitefly 1 Species Found in Florida

Seasonally acclimatized individuals of woolly whitefly Aleurothrixus floccosus (Moskell), cloudywinged whitefly Dialeurodes critifolii Morgan, and Aleurodicus dispersus Russell were exposed to extreme temperatures for 3-h periods and survivorship measured. Survivorship of the 3 whitefly species under field conditions also was followed to determine temperature induced mortality. Summer survivorship was measured during July, Aug., and Sept. in Fort Lauderdale, FL and winter survivorship was measured during Dec., Jan., and Feb. Heat tolerance was the same among the 3 whitefly species and cold tolerance was different with woolly whitefly > cloudywinged whitefly > A. dispersus . The nymphal overwintering stage is an aleyrodid adaption to cold stress in Florida. My data indicate that the abundance of cloudywinged whitefly populations in northern Florida, and range expansion of A. dispersus northward are both limited by winter cold temperatures.