Mealy Bugs on Citrus

Tangerine trees are often attacked by mealybugs.

Citrus trees are often under attack from citrus mealybugs, a common pest of citrus trees. These insects attack many other plants and trees in the landscape, as well as citrus trees. Heavy infestations of mealybugs can affect the health and appearance of the citrus tree, as well as the fruit it bears.

Identification

The citrus mealybug most commonly attacks citrus trees growing in heavy soils or those planted in areas of heavy shade. Humid weather conditions are favorable for the spread of mealybugs. In citrus trees, mealybugs are spread from tree-to-tree by crawling on machinery or by birds and insects. Mealybugs are very small, with females measuring only 3 mm in length and males reaching 4.5 mm at maturity.

Effects

Citrus mealybugs occur most often in older citrus trees and damage tree leaves through feeding. Using their piercing mouthparts, mealybugs suck sap from the leaves, fruit and roots of citrus trees. Trees often defoliate, drop fruit prematurely and fruit splits. Mealybugs excrete a substance known as honeydew, which is sticky and causes sooty mold to develop in citrus trees. Sooty mold is characterized by a black coating of fungus on host trees, which closely resembles chimney soot. Heavy mealybug infestations often result in 80 percent defoliation and 100 percent fruit drop in affected trees, states the University of Arizona.

Monitoring

Monitor your citrus trees for mealybug infestations by placing pheromones and sticky traps in close proximity to trees. Pheromones attract only male mealybugs, but will alert you to their presence. Citrus mealybug monitoring should begin in the month of March. Examine the trunk and lower tree branches for signs of infestation. Continue to monitor citrus trees as the growing season progresses, mealybug damage is most obvious during the summer months.

Control

Mealybug control is a combination of cultural controls and the applications of insecticides. Keeping citrus trees pruned so the branches of trees do not touch each other helps prevent the spread of mealybugs. Natural predators are an effective means of mealybug control. These predators feed on mealybugs, greatly reducing their population. Chemical control products are available for citrus mealybug control. However, mealybugs are often very difficult to control with insecticides.

References

• University of Florida: Scale Insects And Mealybugs On Ornamental Plants: Eileen A. Buss. Jay Cee Turner
• University of Arizona: Citrus Mealybug: David Kerns, Glenn Wright, John Loghry
• NCSU: Mealybugs: Steven D. Frank