Citrus flatid planthopper

The citrus flatid planthopper (Metcalfa pruinosa) is a member of the order Hemiptera and the family Flatidae. Originally native to North America, this species has become a significant invasive pest in Europe and other regions, posing a serious threat to both commercial agriculture and private gardens due to its aggressive colonization behavior.

This insect is a highly polyphagous feeder, known to attack a vast array of host plants. It commonly infests grapevines, citrus trees, pome and stone fruits, berry bushes, and a wide range of ornamental plants. The sheer diversity of its hosts makes it extremely difficult to eradicate once it establishes a permanent presence in a specific area.

The biology of Metcalfa pruinosa involves a single generation per year. The insect overwinters in the egg stage, typically inserted into the bark of host plants. Larvae hatch in late spring and undergo five instars. These nymphs are easily recognizable by the fluffy, white, waxy secretion they produce, which serves as a protective layer against external factors and predators.

Feeding damage is caused by both nymphs and adults piercing plant tissues and sucking phloem sap. This leads to stunted growth, wilting, and reduced plant vigor. Furthermore, the secretion of honeydew promotes the rapid growth of sooty mold fungus, which covers the foliage in a dark film, severely impairing the plant's ability to undergo photosynthesis and reducing crop quality.

Effective management strategies should include a multifaceted approach:

• Frequent monitoring and physical removal of infested shoots during the early stages of the season.
• Application of selective insecticides at the early nymphal stages when the waxy coating is still thin.
• Maintaining good orchard sanitation by eliminating host weeds surrounding the crop.
• Implementation of biological control programs, such as introducing the parasitoid Neodryinus typhlocybae.
• Proper pruning to improve air circulation within the canopy, which makes the environment less favorable for the pest.