About Leafhoppers
These annoying insects, despite their diminutive size, possess an insatiable appetite that belies their small stature. They are notorious not only for their persistence but also for their capability to inflict serious damage on a wide array of crops.
Leafhoppers are considered one of the most ancient insects that have remained unchanged over time. They are harmless to humans and exist in various species.
The causative agent is the insect Emposca sp. | Order: Hemiptera | Family: Cicadellidae/Jassidae
Known species include:
- Empoasca flavescens (F)
- Empoasca lypica (de Berg)
- Empoasca benedettoi
- Empoasca descipiens
Notably, the species found on grapevines are E. lypica, E. vitis, and E. descipiens.
Mouthparts: Piercing and sucking
Harmful Stages: Nymph and adult insect
9 Damages, and Symptoms of Injury
- Leafhoppers extract the sap from leaves, particularly new tender leaves, starting in April and May by piercing the cells and sucking out the sap. This leaves behind pale yellow spots and results in the appearance of very fine holes surrounded by brown coloring not exceeding the size of a pinhead, which over time turns brown, reducing the efficiency of the photosynthesis process.
- White mottling appears on the leaf due to the sap being absorbed from the underside, thus distorting part of the leaf.
- During feeding, the insect secretes toxic saliva that causes physiological disorders in the leaf. Consequently, the leaves display various deformations—they become distorted, wrinkled, twisted, and change color from green to yellowish or mottled green. When exposed to sunlight, green and yellow sections appear. Infected trees also cease to grow.
- When the infection intensifies, brown spots appear on the leaves as a result of tissue death, which develops into leaf burn, often causing the leaves to fall before completing their growth.
- Some viral diseases and certain types of harmful bacteria are transmitted from one plant to another, which can occur in some tree families such as Oak, Sycamore, Elm, and Maple. This may prompt farms to burn infected leaves.
- The injury also plays a role in weakening growth in the following season, and losses may be significant if the injury is neglected for more than two years.
- It secretes quantities of honeydew on which sooty mold fungus grows and dust adheres, affecting the quality of the fruits and thereby reducing the market value of the fruits.
- The nutrition resulting from leafhoppers leads to a decrease in the ability of leaves to perform photosynthesis and build, affecting the quantity and quality of fruits. Severe infections may reduce the sugar content and increase the acidity of the fruits, and prevent coloring, which affects the suitability of these fruits for local consumption and export.
- The plant can tolerate up to 15 insects per leaf without economic damage.
Leafhoppers Invasion
The insect is widespread in Mediterranean countries such as Italy, Spain, Portugal, Albania, Syria, Palestine, and Lebanon. It is also prevalent in some Arab countries such as Saudi Arabia, Iraq, and some Asian countries such as India, and is found in Eastern and Northern Africa.
Host Families
Leafhoppers damage crops because they feed on plant sap. They are characterized by their widespread establishment and quick adaptation. They feed on a variety of families including cotton, sugar beets, okra, potatoes, tomatoes, eggplant, some cucurbits, legumes, as well as grapes, almonds, and citrus fruits. Empoasca lypica infects corn, wheat, legumes, cotton, eggplant, tomatoes, potatoes, okra, green peppers, sugar beets, mallow, peas, alfalfa, cucurbits, almonds, and grapes. While Empoasca descipiens infects vegetable plants, especially eggplant and tomatoes.